Aviation Investigation Report A98H0003

Maintenance and Records

  1. Swissair Operating Specifications
  2. Aircraft Information
  3. Aircraft Maintenance History
    1. Inspection Periods
  4. Powerplant Records History
  5. Supplemental Type Certificates
  6. Swissair's Approved Maintenance Program
    1. Swissair Maintenance Program for McDonnell Douglas MD-11
    2. Swissair Reliability Program Authorization
  7. SR Technics Ltd
    1. Maintenance Organization Operating Specifications
    2. FOCA Certificate
    3. Approval Schedule – Aircraft Ratings
    4. Approval Schedule – Engine Ratings
    5. Foreign Certification
    6. Limited Airframe Rating
    7. Limited Engine Rating
    8. Maintenance Organization Exposition Manual
      1. Introduction
      2. Engineering Order
      3. Training
      4. Technical Training
      5. Continuation Training
    9. Quality System
      1. Responsibility for Quality Assurance
      2. Inspection Levels
    10. Reliability Program
      1. Purpose and Objective
      2. Technical Information System
      3. Incidents and Occurrences
  8. Reporting of Defects
    1. SR Technics Reporting Procedures
    2. Mechanical Reliability Reports
    3. Technical Incidents
    4. Service Difficulty Reports
  9. Maintenance Review
    1. Introduction
    2. SR Technics Status List of Engineering Orders
      1. Engineering Order Review Results
    3. MD-11 Airworthiness Directives
    4. Service Bulletins
    5. Daily Technical Reports
    6. Pilot Complaints
    7. Non-routine Structural Maintenance from Last "D Check"
    8. Structural Significant Inspection Items from Last "D Check"
    9. Time-Controlled Components
    10. Aircraft Technical Records
      1. Technical Logbooks
      2. "A Check" Review
      3. IFEN System Maintenance Activity Review
  10. Audits
    1. SR Technics Internal Audit
    2. FOCA Audits
      1. Corrective Actions

Swissair Operating Specifications

SWR holds the following operating certificates:

  • FOCA (a member of the JAA) AOC 1017, issued 31 March 1998. Authorized for passenger and cargo operations for the following aircraft: B747-357, MD-11, A310-322, A310-325, A319, A320, and A321.
  • US Department of Transportation, FAA Operations Specifications (En Route Authorization/Limitations/Procedures) Certificate SWRF3221, approved 20 June 1997. Authorized for the following aircraft: B747, A310, and MD-11.
  • Canadian Department of Transport Operating Certificate F-1945 (Foreign Air Carrier), approved 4 December 1995.

Aircraft Information

The FOCA Certificate of Registration issued 5 August 1991 for HB-IWF Swissair lists the following information:

Registered owner's name and address

Blue Ridge Finance Ltd.
c/o CODAN Services Ltd.
Clarendon House, Church Street
Hamilton HM CX, Bermuda

Registered operator's name and address

SWISSAIR, Schweiz
Luftverkehr AG, Postfach
8058 Zurich-Flughafen

Additional aircraft information

Fuselage: 465
Export Certificate of Airworthiness (FAA): E274821
Number of lavatories: 9
Number of galleys: 14
Equipped for over-water operation: Yes

Aircraft Maintenance History

Table: Aircraft Maintenance History

Aircraft Total Time to 2 September 1998 36 041 FH
Aircraft Total Cycles to 2 September 1998 6560
Last "A Check" Completed 10 August 1998 35 687 FH
Last "C Check" Completed 10 September 1997 30 696 FH
Last "D Check" Completed 10 September 1997 30 696 FH

Inspection Periods

Table: Applicable Checks

Maintenance Pre-flight Check Before Each Departure

"A check" 700 FH
Note: Escalation of "A check" from 600 to 700 FH was effective 1 October 1997.

"C check" 6 000 FH
Note: Escalation of "C check" from 5 200 to 6 000 FH was effective 1 April 1995.

"D check" 30 000 FH/72 months, whichever occurs first.
Note: Escalation of the first "D check" from 22 400 FH/60 months to 30 000 FH/72 months was effective 1 June 1996. After the first "D check," the interval is reduced to 22 400 FH/60 months, whichever occurs first.

A review of the maintenance records verified that all requirements of the approved maintenance program were completed on time or within the tolerance granted to Swissair by the FOCA.

Powerplant Records History

The aircraft was delivered to Swissair with three Pratt & Whitney PW4460 model engines installed. McDonnell Douglas SB 72-001, to convert the PW4460 to the PW4462 model, was incorporated on 1 October 1997 under EO 069685.02. At the time of the accident the aircraft was equipped with three Pratt & Whitney PW4462 model engines.

The Engine Condition Trend Monitoring Reports from 16 June to 1 September 1998, and the Engine Trend Monitoring Watch-List of Swissair PW4462 engines were reviewed; there were no discrepancies directly pertinent to the investigation.

Engine 1 (SN P723896CN) was removed from aircraft HB-IWG (Swissair) on 2 February 1998, because of performance deterioration. The incoming inspection of the filter and magnetic plug revealed no deposits. Because of engine time accumulated, it was decided that the engine should be overhauled. Normal wear was indicated. High-pressure turbine T1 blades were excessively worn at the tips, and ceramic duct segments were spalled. The T2 rotating air seal was replaced because of a crack. Extensive overhaul maintenance was performed on all areas of the engine, and an engine test was performed in a test cell on 6 April 1998. A module analysis assessment was performed to evaluate performance standards. Total flight hours were 25 753 and total cycles were 4 290. The Engine Condition Report and Engine Test Summary Log were reviewed; there were no discrepancies directly pertinent to the investigation.

Engine 2 (SN P723856CN) was removed from aircraft HB-IWH (Swissair) on 12 June 1997, for modification. The incoming inspection of the filter and magnetic plug revealed no deposits. Normal wear was indicated. The T2 rotating air seal was replaced because of a crack, and standard overhaul maintenance was performed on other areas of the engine. An engine test was performed in a test cell on 11 August 1997, and a module analysis assessment was performed to evaluate performance standards. Total flight hours at this time were 24 770 and total cycles were 4 439. The Engine Condition Report and Engine Test Summary Log were reviewed; there were no discrepancies directly pertinent to the investigation.

Engine 3 (SN P733713) was removed from aircraft PH-MCS (Martinair) on 5 April 1996 as a result of an in-flight shutdown. The incoming inspection of the filter and magnetic plug revealed no deposits. The engine disassembly revealed that a fractured T2 blade caused heavy secondary damage to the high-pressure compressor, diffuser case assembly, high-pressure turbine, low-pressure turbine, and main gearbox. Extensive overhaul maintenance was performed on all areas of the engine and an engine test was performed in a test cell on 4 October 1996. A module analysis assessment was performed to evaluate performance standards. At the time of this maintenance, total flight hours were 4 735 and total cycles were 861. The Engine Condition Report and Engine Test Summary Log were reviewed; there were no discrepancies directly pertinent to the investigation.

Supplemental Type Certificates

SR Technics aircraft records indicated four STCs incorporated on HB-IWF:

STC ST01373AT
Issued: 9 June 1997
Description: Interior Reconfiguration (Product 97)
Holder: J.R.G. Design, Inc.
Greensboro, NC, USA
STC ST00698AT-D
Issued: 8 September 1996
Description: Installation of Airshow 420 System
Holder: TIMCO
Greensboro, NC, USA
STC ST00236LA-D
Issued: 19 November 1996
Description: Installation of Interactive Flight Technologies Inc. Entertainment System
Holder: Santa Barbara Aerospace
Santa Barbara, CA, USA
STC TD340LB-T
Issued: 16 May 1994
Description: Interior Modification, (Cabin Crew Rest)
Type Design Designated Engineering Representative Approval
Holder: McDonnell Douglas Corp.
Douglas Aircraft Company
Long Beach, CA, USA

Swissair's Approved Maintenance Program

The FOCA Maintenance System Approval Statement (AOC 1017) certified that Swissair was approved under JAR-OPS 1 Subpart M to manage the maintenance of the following aircraft:

Table: Approved Maintenance Programs

Aircraft Type Approved Maintenance Program
A310-322 45-0002
A310-325 45-0002
A319 48-0002
A320 48-0002
B747-357 46-0002
MD-11 49-0002

The SR Technics Engineering department was responsible for the maintenance programs for all Swissair aircraft, with the exception of the B747, which had been subcontracted to KLM.

Swissair Maintenance Program for
McDonnell Douglas MD-11

The FOCA approved the Swissair maintenance program for MD-11 aircraft with the following conditions:

  • All amendments/alterations to the maintenance program were to be approved by the FOCA.
  • It was the responsibility of Swissair to ensure recommendations made by the aircraft or equipment manufacturers were evaluated and, where appropriate, Swissair was to initiate maintenance program amendments.
  • It was the responsibility of Swissair to ensure compliance with all appropriate mandatory requirements issued by the FOCA, and by the recognized airworthiness authority of the country of origin of the aircraft.

Swissair Reliability Program Authorization

The FOCA authorized Swissair to participate in the SR Technics MD-11 Reliability Program (98-37146) under the condition that the SR Technics Reliability Program was considered part of the approved Swissair Maintenance Program.

SR Technics Ltd.

SR Technics was composed of eight organization areas: Maintenance, Powerplant, Components, Materiel, Engineering and Quality, Finance, Human Resources, and Marketing and Sales. Each of these had a supporting structure to meet their specific business needs. For example, the supporting structure for Maintenance included the following:

  1. Engineering
  2. Management Support
  3. Customer Business and Support
  4. Planning
  5. Workshops
  6. Heavy Maintenance
  7. Line Maintenance Hangar
  8. Line Maintenance Ramp
  9. Line Stations

Maintenance Organization Operating Specifications

SR Technics had the following certifications:

  1. FOCA Maintenance Organization Approval Certificate FOCA-001, current issue 14 February 1997, expiry date 27 June 1999;
  2. United States Department of Transportation, FAA Air Agency Certificate SWRY3221 (approved Repair Station) original issue 20 February 1952, current issue 31 July 1998, expiry date 30 June 1999; and
  3. ISO 9001, re-certification December 1995.

At the time of the accident, based on an authorization issued by the FOCA, SR Technics' Engineering department was authorized to release its own maintenance instructions and to amend maintenance instructions issued by the manufacturer of aircraft, engines, components, or both as described in the MOE. This particular Engineering approval was not applicable to SR Technics' FAA Repair Station certificate.

FOCA Certificate

The FOCA Approval Certificate certified SR Technics as a JAR-145 maintenance organization approved to maintain the products listed in the Approval Schedule, issued 24 April 1998, expiry date 24 October 1998.

Approval Schedule – Aircraft Ratings

The extent of maintenance that can be performed is specific to aircraft type and series.

Table: Aircraft and Maintenance Type

Aircraft Model Base Maintenance Line Maintenance
McDonnell Douglas DC-9 / MD-80 / DC-10 / MD-11 Series 1 2
Airbus A310 / A319 / A320 / A321 / A330 Series
Airbus A300 / A340 Series   2
Boeing 737 / 757 / 767 / 777 Series
Fokker F28 MK0100 (F100) 3 2
Boeing 747 Series
1: "C check," Intermediate Visit, Heavy Maintenance Visit, "D check"
2: Pre-flight up to and including "B check" (where applicable)
3: "C check" only

Approval Schedule – Engine Ratings

The extent of maintenance that can be performed is specific to engine type and series.

Table: Engine Type and Maintenance

Limitation
Pratt & Whitney JT8D Series Repair and Complete Overhaul
Pratt & Whitney JT9D Series Repair, Inspection, Modification, Quick Engine Change Buildup and Limited Parts Refurbishment
Pratt & Whitney PW4000 Series Repair and Complete Overhaul
CFM International CFM 56-5 and -7 Series Repair and Complete Overhaul

Foreign Certification

The FAA empowered SR Technics to operate an approved Repair Station with the following ratings:

Table: Repair Station Ratings

Limited Airframe 28 November 1997
Limited Engine 9 September 1993
Limited Emergency Equipment 21 February 1995
Limited Specialized Services 31 July 1998
Limited Accessory 20 February 1997
Limited Instruments 20 February 1997
Limited Radio 20 February 1997

Limited Airframe Rating

Boeing Airplane Company Model B747 100-200-300 (Note 2)
Model B747-400 (Note 1)
McDonnell Douglas Model DC-9/MD-80 Series (Note 2)
DC-10 Series, MD-11 Series (Note 3)
Airbus Industrie Model A310-200/-300 Series (Note 3)
Model A319, A320 and A321 Series (Note 2)
Note 1: Aircraft inspections through "A check" or equivalent and related aircraft maintenance. This does not authorize overhaul or repair of airframe components, airframe appliances, or both, except within the limitations listed in SR Technics FAA accepted-capability list dated 4 February 1997, as revised.
Note 2: Aircraft inspections through "C check" or equivalent and related aircraft maintenance, including overhaul or repair of airframe components, appliances, or both.
Note 3: Aircraft inspections through "D check" or equivalent and related airframe maintenance including overhaul or repair of airframe components, appliances, or both.

Delegated Authorities: None

Limited Engine Rating

Pratt & Whitney JT8D Series (Note 1)
JT9D Series (Note 2)
PW4000 Series (Note 1)
CFM International S.A. CFM56 Series (Note 1)

Note 1: Engine authorization for the aforementioned engines is limited to overhaul and repair of engines in accordance with the applicable engine manufacturer's maintenance manual, as revised.

Note 2: Engine authorization for the aforementioned engines is limited to inspection, minor repair, adjustment, removal and installation of accessories on the above engines. This does not authorize overhaul or repair of engine components, engine appliances, or both, except within the limitations in SR Technics' FAA-accepted capability list, as revised.

Delegated Authorities: None

Maintenance Organization Exposition Manual

Introduction

The purpose of the MOE manual (effective date 1 March 1997) was to describe the procedures and policies of SR Technics. Compliance with these procedures assures conformity with the applicable regulations, appropriate manufacturers' manuals, and other approved data, all of which are necessary to obtain and retain certificates and ratings. The MOE is a combined manual covering FOCA/JAA and FAA requirements, and cross-references subjects required by the FAA Foreign Repair Station Inspection Procedures Manual Guidance and Reference Material. The responsibility for compliance with the provisions of the MOE rested with the general managers of the different organizational areas.

Engineering Order

An EO is the means by which the Engineering department provides instructions to the applicable work groups to perform specific work activities. EOs originate from an AD, manufacturers' recommendations (e.g., SBs, AOLs;), or from SR Technics internal decisions. An EO can also be generated to incorporate modifications, implement changes in the maintenance programs and fleet inspections, or both. They are published in written form, and compliance is mandatory. An EO deadline date is an agreed-upon date based on the requirements of the Engineering department and of other departments as deemed necessary. This date can be modified, unless the EO is related to an AD, upon approval by the Engineering department. Modifications to the deadline date can be attributed to a variety of reasons, such as availability of vendor-supplied parts.

Training

The Technical Training Committee, training coordinators, supervisory personnel, QA departments, and the Personnel Development and Technical Training department worked together to ensure that there were appropriately qualified and trained personnel within SR Technics.

The Technical Training Committee was chaired by the head of the Personnel Development and Technical Training department and included representatives from all product areas. This committee was responsible for issues pertaining to overall training, including ensuring that the training corresponded with the objectives of SR Technics. Additionally, the committee provided information to managing personnel about the level of training in each product area.

Each assigned training coordinator was responsible for training issues, and for ensuring that decisions made by the Technical Training Committee were communicated within their specific product areas.

Within their specific work areas, the supervisory personnel were responsible for introducing a new employee to the workplace, establishing training requirements for each employee, providing on-the-job training, and keeping a training record for each employee.

Each QA department was responsible for controlling and approving the special procedures for certifying staff. These procedures included qualification profiles and training requirements.

The Personnel Development and Technical Training department was responsible for executing classroom and practical training and for keeping records of training that had been provided.

Technical Training

The MOE describes the training program as including:

Basic Training

Basic training mainly consisted of an introductory course, basic courses, and courses specific to aircraft types.

All new employees received an introductory course on their first day of employment. This included a general presentation of the company, personnel regulations, and a workshop tour in the maintenance base.

Basic courses provided general knowledge about aeronautical and technical subjects, selected English expressions, and practical instructions on the use of SR Technics work documents and the application of proper methods and routines for carrying out maintenance work. Additionally, these courses included instructions regarding QA, safety regulations, fire protection, and general familiarization with Swissair's documentation, policies and procedures.

The aircraft-type basic courses consisted of general information about each current aircraft type and supplementary information about the main aircraft sections or systems specific to the area where the employee was to work.

New employees who had completed their basic training and were working for the first time on an aircraft or in the workshop were to be accompanied and supervised by a qualified person until sufficient knowledge had been obtained.

System Training

System training, both theoretical and practical, provided the employee with the specific knowledge and skills needed to meet the requirements of an airframe, powerplant, and electric/avionics specialist, or both.

Special Training

Special training provided the employee with the knowledge and skills to meet the requirements of each specific course, such as engine overhaul, run-up, and component overhaul. CAA regulation training was to be provided to supervisory and engineering personnel as well as to all certifying staff.

On-the-job training, as far as possible and practical, was to be prepared and carried out according to the same principles as basic and special training.

Each course was followed up with a test and, upon passing with a minimum of 70%, the employee was then permitted to work independently and to sign the work documents.

Continuation Training

A continuous evaluation process was used to determine the training requirements beyond what was addressed in the Basic, System, Special, and on-the-job training. It was the responsibility of the head of each department to determine the type and extent of this continuation training.

Quality System

Responsibility for Quality Assurance

Within the Engineering and Quality organization area there were three QA departments. QA Aircraft was assigned to the Aircraft Maintenance and Aircraft Overhaul organization areas, QA Components was assigned to the Components and Power Plant organization areas, and QA Services was assigned to the remaining organization areas. QA was responsible for the performance of required inspections and for planning and performing internal quality audits of the organizational procedures. These departments reported directly to the head of Engineering and Quality, who was responsible for ensuring adherence to the quality standards and requirements for the CAAs, and for ensuring the established quality system was reviewed for compliance with the quality standards, the government and CAA rules, and the company's regulations.

QA for SR Technics products, particularly the airworthiness of the aircraft and the use of aircraft parts, was the responsibility of the implementing departments, in accordance with relevant job descriptions and procedures.

Each employee was to be trained to be personally responsible for the quality of his or her work. The work was expected to be accomplished correctly, and the employee was required to perform a "self inspection" after each work step.

The supervisors of all individual departments were responsible for the following:

  • QA in their specific areas;
  • ensuring their personnel were aware of the required standards, were sufficiently trained and qualified, and had access to appropriate resources;
  • inspecting the quality of their employees' work; and
  • coordinating QA measures.

Inspection Levels

There were three levels of inspection: Self, Double, and Required. These inspection levels were determined by a team of specialists, based on two criteria: an analysis of the risk inherent in the performed work and an analysis of the probability and consequences of a failure. Double and Required inspections were only performed in production areas. In administrative areas the requirements for Double inspections were included in internal procedures, wherever appropriate.

The MOE defined Self, Double, and Required inspections in the following ways.

Self Inspection

A Self inspection is required after each work step and is performed by the person who actually did the work. Personnel performing this work must be trained and qualified, and the work must be done in accordance with the applicable regulations, and instructions, procedures, or both.

Double Inspection

A Double inspection may be required based on the probability of a failure during the execution of the work and the consequences thereupon. This inspection must always be carried out by a specially trained and qualified person who is not involved in the execution of the work to be inspected, and must be recorded on the applicable working paper. The Self inspection must be carried out prior to performing a Double inspection.

Required Inspection

A Required inspection is to be performed if the probability of a failure during the execution of the work may consequently lead to unsafe operation of the aircraft. This inspection must always be carried out by a specially trained and qualified inspector from the QA department assigned to the product area, and must be recorded on the applicable working paper. The Self inspection must be carried out prior to performing a Required inspection.

Reliability Program

In accordance with FAA AC 120-17A, administration of the Reliability Program can be assigned to an existing organizational element. In this case, the SR Technics engineering organization: CEA, CRE, or both.

Regular meetings were scheduled with the Engineering, Maintenance and Quality departments of SR Technics for the purpose of reviewing reliability aspects such as operating performance, airworthiness, and reliability in general.

Purpose and Objective

The program's purpose was to establish a management and control system for optimizing aircraft, system, engine and component performance and service life, and to effectively adjust time limitations related to operating experience. The objective of the program was to control and maintain components, systems, and aircraft operated by customers within an acceptable level of airworthiness, reliability, and economics.

Technical Information System

SR Technics and the subcontractors' reliability program obtained data from several sources (through the Technical Information System), and the development of this information provided the means for analysing operating experience and quality, and formulating projections. According to the SR Technics procedure manual applicable at the time of the accident, the customer airlines and SR Technics reported to each other all technical information necessary for control of the technical behaviour of the flight equipment. This information was sent to the CEA, which had the sole and exclusive responsibility for fulfilment of all engineering activities. Although the agency could partially delegate responsibilities to other parties, subject to SR Technics and subcontractors' Engineering Group approval, the overall responsibility still rested with the agency.

The CRE group was responsible for engineering activities related to components (including engines) within SR Technics and the subcontractors.

The responsible CEA/CRE group analyzed the collected data and made recommendations for time extensions, corrective actions, or additional investigations. The primary objective of these analyses and decisions was to maximize operational safety and airworthiness, and to optimize operational integrity and reliability.

Incidents and Occurrences

All technical events that had a direct influence on flight safety or had negative operational consequences leading up to "emergency procedures" or abnormal operations were considered as incidents. Technical events or consequences that were not classified as incidents were considered occurrences.

Reporting of Defects

SR Technics Reporting Procedures

SR Technics was required to report to the FOCA, the manufacturer, and, where applicable, the operator any un-airworthy condition found during maintenance that might have seriously compromised the airworthiness of the aircraft. The Engineering department would provide information to the liaison aviation authorities, who in turn were to submit the report to the FOCA. This information would be reported to the FOCA within three days, and submitted on special forms.

As an FAA-approved foreign repair station, SR Technics was required to report, with respect to United States-registered aircraft, any serious defect in, or other recurring un-airworthy condition of any aircraft, powerplant, propeller, or a component of any of them. These reports were to be submitted to a central collection point as specified by the FAA administrator, and in a format acceptable to the administrator. SR Technics used FAA Form 8010-4, Malfunction or Defect Report, for this purpose. The completed form was to be forwarded to the liaison aviation authorities who, in turn, were to submit the report to the FAA.

Although SR Technics did not differentiate between airlines in their treatment of these events, they did not, nor was there a need to, forward any reports to the FAA with respect to the Swissair fleet.

Mechanical Reliability Reports

The 14 CFR, Part 129, did not require Swissair to provide mechanical reliability reports to the FAA.

Technical Incidents

The technical incident information was included in the MD-11 monthly reliability reports, which at the time of the accident included data for Swissair, KLM, Garuda, Thai International, Citybird and Martinair. This report was presented in such a manner that each airline had its own section, and each section contained reports titled Technical Incidents & Occurrences and Technical Incident Description.

The Technical Incidents & Occurrences report identified the number of incidents per month, the number of occurrences per month, and the consequences of these events per month. The categories for each of these sections are based on 14 CFR, Part 121.703, requirements.

The Technical Incident Description report included the following:

  • Aircraft Registration
  • Date
  • Operational Phase
  • Station
  • Length of Delay
  • Applicable Air Transport Association chapter
  • Description (including action taken by flight crew and brief description of incident)

The following technical incidents, described in the MD-11 monthly reliability reports from September 1997 to September 1998, were reviewed:

  • HB-IWC - On 23 January 1997 smoke was observed and smelled; then the overhead integral lights went off. CB C-13, in the overhead switch panel, was pulled, and the situation improved. The overhead instrument lighting dimmer was subsequently replaced.
  • HB-IWG - On 25 January 1997 smoke was smelled in the C-class cabin while passengers were disembarking. Six main electrical and six galley power feeders were subsequently replaced.
  • HB-IWH - On 5 June 1997 all six cockpit display units were temporarily locked out. The three DEU CBs were cycled and the indications returned to normal. Subsequent inspection of the three DEUs did not identify any discrepancies that could be related to this incident.
  • HB-IWA - On 21 November 1997 there was an electrical fire in the area of first class seat 1B. Although the first class section was configured for the IFEN system (20 August 1997), the IFEN-equipped first class seats were yet to be installed. The seat power cable was found to be chafing against the seat structure, resulting in arcing of the wires. This arcing created sparks that caused localized scorching of the adjacent carpet and precipitated the "LH OUTBD PAX SEAT PWR" CB to "pop." The seat power cable was subsequently changed.

A review of earlier technical incidents identified one that was considered potentially pertinent to the investigation:

  • On 12 July 1994 SR Technics had reported a technical incident to McDonnell Douglas in which maintenance technicians noticed smoke in the cabin following a "C check" engine run-up. An investigation revealed the centre accessory compartment was filled with smoke, and the battery and battery charger were overheated. It was determined that the source of the smoke was a failed transformer inside the battery charger. The FAA was notified and a vendor advisory was issued that indicated a random component failure, most likely caused by an inner winding short introduced during manufacture. It was determined that no further action was required, and the incident was closed.

Service Difficulty Reports

The FAA's SDR system is designed to collect, analyse, record, and disseminate data concerning defects and malfunctions that have resulted in, or are likely to result in, a safety hazard to an aircraft or its occupants. The anticipated outcome of the system is to use the reported information to support regulatory activities required to improve the level of flight safety. At the time of the accident, the SDR database included reports for commercial and general aviation aircraft in the USA and Canada.

The SDR is a feedback system, which depends on a wide network of contributors. Due to the mandatory and seemingly consistent nature of SDR reporting, this data is considered to be the best available. Nevertheless, caution must be applied to the interpretation of the data as, for the most part, it contains unverified information whose quality is highly dependant on the reporter's knowledge, experience, and judgement.

Maintenance Review

Introduction

Among the requirements for obtaining a Type Certificate in the USA, the applicant (manufacturer) must provide "Instructions for Continued Airworthiness," as defined in FAR 25.1529, and Part 25, Appendix H, in the form of a manual or manuals. These instructions must provide maintenance instructions that include (or refer to) scheduling information that provides the recommended periods for cleaning, inspecting, adjusting, testing, and lubrication, and the degree of inspection, the applicable wear tolerances, and work recommended at these periods. There must also be an inspection program that includes the frequency and extent of the inspections necessary to provide for the continued airworthiness of the aircraft. It is mandatory that applicants comply with the Instructions for Continued Airworthiness and all ADs in order to maintain the aircraft's Certificate of Airworthiness.

As described in SR Technics' MOE:

  • Adjustments to Airworthiness Limitation Items, Certification Maintenance Requirement Items, Life Limits and ETOPS requirements are allowed only if approved by the state of manufacture of the aircraft or engine; and
  • Changes in the content or the interval of a repetitive inspection based on an AD may only be approved by the state of manufacture of the aircraft, engine or component, or by the CAA of the country where either the aircraft is registered or where the engine or component is installed.

SR Technics Status List of Engineering Orders

The SR Technics Status List of Engineering Orders is a record of EOs relating to a particular model of aircraft. The list includes

  • EO number
  • ATA chapter [according to ATA 100 index]
  • Nature of document [i.e., document type]
    • SB [Service Bulletin, aircraft manufacture]
    • AD [Airworthiness Directive]
    • OL [All Operators Letter]
    • TO [Technical Order, from partner airline]
    • IA [Engineering Order]
    • VB [Vendor Bulletin, component manufacture]
    • SL [Service Letter]
    • MO [Modification Order]
    • WS [Work Statement]
  • Publisher/Editor of Document or Engineering Order [three-letter code]
  • Subject [title of document]
  • EO type code:
    • A [Task on aircraft only]
    • B [Task on aircraft and component]
    • C [Task on component only]
  • Status code per aircraft registration:
    • + [to be performed]
    • – [not to be performed]
    • U [unfinished]
    • P [finished]
  • Date Performed
  • EO Deadline

Engineering Order Review Results

The Status List of Engineering Orders generated for HB-IWF (dated 5 October 1998) identified 2 597 entries:

  • 95 identified as AD, with the publisher being FAA;
  • 6 identified as AD, with the publisher being FBV;
  • 12 identified as MO, with the publisher being SWR;
  • 50 identified as OL, with the publisher being MDC;
  • 27 identified as OL, with the publisher being Pratt & Whitney Aircraft;
  • 1 identified as an SB, with the publisher being Garrett;
  • 1071 identified as SB, with the publisher being MDC;
  • 8 identified as SL, with the publisher being a variety of vendors;
  • 30 identified as TO, with the publisher being a partner airline;
  • 341 identified as VB, with the publishers being various vendors (excluding Pratt & Whitney Aircraft);
  • 236 identified as VB, with the publisher being Pratt & Whitney Aircraft; and
  • 21 identified as WS, with the publisher being SWR.

Additionally, there were 699 entries for EOs produced by the SR Technics Engineering department for work that they deemed necessary. These EOs are not identified by a document type nor are they identified by publisher.

The investigation reviewed each entry. Pertinent EOs are discussed in the MD-11 Airworthiness Directives and Service Bulletins sections, which follow.

MD-11 Airworthiness Directives

Although ADs issued after the date of the accident are not applicable to
HB-IWF, because the aircraft was destroyed, they were reviewed for the purpose of determining if any were related to the area of heat damage or specifically to smoke events in the cockpit and forward cabin ceiling area. A review of the FAA-issued MD-11 ADs from the date of the accident to April 2001 (based on the FAA's AD list, published April 2001) identified 15 that were considered pertinent to the investigation. At the time of the accident there were no EOs for these ADs, nor was there a requirement for there to be any.

The following ADs refer to SBs that were issued prior to 1 September 1998.

AD 98-24-02 "To prevent an electrical failure in the dimmer control for the overhead instrument panel light and circuit breaker light plate due to overheating of a printed circuit board (PCB) capacitor in the dimmer control, which could result in rupture of the capacitor and smoke in the flight compartment." This AD became effective on 30 November 1998 and refers to SB MD-11-33-045, dated 14 June 1995. SR Technics had accomplished SB MD-11-33-045 under EO 217044 on 12 September 1997.
AD 00-03-11 "To prevent burnt internal circuit boards caused by a short in either the engine or airfoil anti-ice valve, or windshield anti-ice controller, which could result in smoke in the cockpit." This AD became effective 23 March 2000 and refers to ASB MD-11-30A020 R3, dated 5 May 1999. ASB MD-11-30A020 R3 was published to notify operators that SB MD-11-30-020, dated 6 March 1995, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-30-020 (including revisions R1 and R2) under EO 510051.01 on 24 July 1996. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-03-13 "To prevent the wire bundles contained in the feedthrough from contacting the bottom of the feedthrough which could cause cable chafing, electrical arcing, and smoke in the cockpit." This AD became effective 23 March 2000 and refers to ASB MD-11-24A041 R1, dated 26 April 1999. ASB MD-11-24A041 R1 was published to notify operators that SB MD-11-24-041, dated 30 September 1992, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-24-041 under EO 099630 on 20 July 1993. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-07-17 "To ensure the upper main circuit breaker panel opens fully." This AD became effective 19 May 2000 and refers to ASB MD-11-24A130 R1, dated 20 September 1999. ASB MD-11-24A130 R1 was published to notify operators that SB MD-11-24-130, dated 2 December 1997, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-24-130 under EO 217077.01 on 22 November 1996. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-07-21 "To prevent wire chafing of the control panel of the auxiliary power control unit (APU) and resultant arcing due to insufficient clearance between the wire bundles and the aircraft structure, which could result in smoke and fire in the flight deck." This AD became effective 19 May 2000 and refers to ASB MD-11-24A116 R1, dated 11 October 1999. ASB MD-11-24A116 R1 was published to notify operators that SB MD-11-24-116, dated 14 May 1997, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-24-116 under EO 217186 on 11 May 1998. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-24-11 "To prevent chafing of certain wires above the forward passenger doors, which could result in an electrical fire in the passenger compartment." This AD became effective on 8 January 2001 and refers to ASB MD-11-25A194 R6, dated 27 January 2000 and MD-11- 24A068 R1, dated 8 March 1999. ASB MD-11-25A194 R6 was published to notify operators that SB MD-11-25-194, dated 15 March 1996, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-25-194 (including three revisions) under EO 511220 on 12 September 1997. ASB MD-11-24A068 R1 was published to notify operators that SB MD-11-24-068, dated 15 February 1994, has been elevated to "ALERT" status. SR Technics had accomplished SB MD-11-24-068 under EO 099828 on 20 December 1994. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems. AD 00-24-11 supercedes AD 00-03-10, which superceded AD 98-25-11 R1, which superceded AD 98-25-11.

The following ADs refer to SBs, where applicable, issued after 1 September 1998.

AD 99-03-02 "To prevent electrical arcing of certain wiring, which could cause a fire and/or smoke in the cockpit or cabin." This AD became effective 12 February 1999 and is the result of examinations conducted in support of an accident investigation. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 99-20-08 "To prevent possible confusion as the flight crew performs their duties in response to a smoke/fumes emergency, which could subsequently impair their ability to correctly identify the source of the smoke/fumes, and subsequently affect the continued safe flight and landing of the aircraft." This AD became effective 13 October 1999 and is related to the FAA's special certification review of the IFEN-system approved STC.
AD 00-14-12 "To prevent a possible flammable condition, which could result in smoke and fire in the forward crew rest area." This AD became effective 23 August 2000 and refers to ASB MD-11-25A233, dated 9 June 1999. ASB MD-11-25A233 was published in response to SB AIM-MD-11-25-2, Revision C, dated 8 March 1999 issued by AIM Aviation Incorporated. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-15-13 "To prevent smoke and possible fire in the overhead switch panel lighting circuitry due to an overload condition, as a result of lack of circuit breaker protection." This AD became effective 23 August 2000 and refers to ASB MD-11-33A027, dated 10 March 1999; Revision 1, dated 2 June 1999; Revision 2, dated 12 June 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems, and supercedes AD 99-09-04, dated 7 May 1999.
AD 00-15-14 "To prevent propagation of smoke and fumes in the cockpit and passenger cabin due to an inoperable remote control circuit breaker (RCCB) of the alternating current (AC) cabin bus switch during smoke and fume isolation procedures." This AD became effective 23 August 2000 and refers to ASB MD-11-24A181, dated 27 June 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-24-10 "To prevent insufficient clearance and contact between the B7-28 bus and an adjacent panel, which could result in arcing damage, smoke and/or fire in the upper main circuit breaker panel." This AD became effective 8 January 2001 and refers to ASB MD-11-24A180, dated 4 January 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-24-14 "To prevent damaged electrical wires or damaged door actuation cables due to chafing by the cables during operation of the forward passenger door, which could result in electrical arcing and consequent smoke in the area above the forward passenger door." This AD became effective 8 January 2001 and refers to ASB MD-11-24A182, dated 3 April 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-24-15 "To prevent electrical arcing and/or heat damaged wires due to improper wire installations during manufacture and/or maintenance of the aircraft, and consequent fire and smoke in various areas of the aircraft." This AD became effective 8 January 2001, and refers to SBs: MD-11-24-171 R1, MD-11-24-170 R, MD-11-24-167 R1, MD-11-24-165 R1, MD-11-24-163 R1, MD-11-24-188 R1, MD-11-24-161 R1, and MD-11-24-162 R1, all dated 6 November 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems.
AD 00-26-15 "To detect a broken light bulb housing and the resultant exposed power contactor, which could cause the Captain, First Officer, or Right Observer map light to short or overheat, and consequent smoke or fire in the cockpit." The AD became effective 17 January 2001 and refers to ASB MD-11-33A069 R1, dated 30 November 2000. This AD is included in the FAA's Corrective Action Plan to address potential MD-11 wiring problems, and supercedes AD 00-07-02.

SR Technics subsequently generated EOs to address each of these ADs.

Service Bulletins

A review of the SR Technics Status List of Engineering Orders identified

  • 513 SBs as having been "performed";
  • 2 SBs as being "underway";
  • 31 SBs "to be performed";
  • 94 SBs "not to be performed"; and
  • 21 SBs as having no Status Code.

A review of the applicable Pratt & Whitney engine SBs did not identify any that were pertinent to the investigation.

A review of the aircraft manufacturer's issued MD-11 SBs up to the time of the accident identified 16 that were pertinent to the investigation (excluding those addressed in the discussion of Airworthiness Directives). Included in these were SBs related to events that could cause chafing, arcing, sparking, smoke, or all in the cabin or cockpit.

MD-11-21-079 "Modify cockpit overhead diffuser assembly." This SB was issued 1 January 1996 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-24-055 "Revise DC Bus 2 and DC Ground Service Bus control wiring." This SB was issued 28 June 1994, revision R02 was issued 20 February 1994, and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics had accomplished this SB (including R02) under EO number 099802.01 on 26 January 1996.
MD-11-24-110 "Inspect/Insert contact pins in power distribution busses." This SB was issued 27 April 1998 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the first convenient check period, but not to exceed 18 months from issue date. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-24-127 "Install cover on overhead circuit breaker panel." This SB was issued 1 October 1997 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics Status List of Engineering Orders shows this SB to be accomplished under EO 217258 with an EO deadline of 30 September 1999.
MD-11-25-071 "Modify the left and right side cockpit liners in the area of the map lights." This SB was issued 19 November 1993 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics had accomplished this SB under EO 099729.01 on 3 May 1994.
MD-11-25-115 "Install insulation on bare metal in flight compartment." This SB was issued 21 October 1992, revision R01 issued 11 November 1997, and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics had accomplished this SB under EO 508676 on 3 May 1994.
MD-11-25-148 "Replace weak springs in the hinges of the slide/raft cover with stronger springs." This SB was issued 10 March 1995 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics had accomplished this SB under EO 511015 on 20 October 1995.
MD-11-25-179 "Replace forward left and right passenger door flapper panel torsion spring." This SB was issued 22 June 1995, revision R02 issued 15 July 1996, and is applicable by fuselage number effectivity to
HB-IWF. Douglas Aircraft Company recommends that this modification be accomplished at the first convenient check period after receipt of parts, but not to exceed 12 months from the issue date of revision R02. SR Technics had accomplished this SB under EO 511144 on 12 September 1997, during the aircraft's first heavy maintenance visit. SR Technics considered this to be the earliest convenient check period to accomplish the SB.
MD-11-25-200 "Replace insulation blankets in the nose, passenger, and cargo compartments." This SB was issued 31 October 1997, revision R01 issued 20 March 1998, and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-33-014 "Replace the right observer's map light support assembly in the flight compartment with a newly designed canted support assembly." This SB was issued 17 September 1991, revision R01 issued 5 June 1992, and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-33-015 "Modify and re-identify 15-0245-5 pedestal light assembly per Grimes Aerospace Service Bulletin 15-0245-33-0012." This SB was issued 20 September 1991 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics accomplished this SB under EO 096388 on 29 September 1992.
MD-11-33-021 "Replace the entry work light fixture at forward left passenger door." This SB was issued 31 August 1992 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics accomplished this SB under EO 099614 on 7 May 1993.
MD-11-33-42 "Modify entry door lighting ballast bracket." This SB was issued 27 July 1994 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-33-045 "Modify dimmer controls for overhead instrument panel light and circuit breaker lightplate." This SB was issued 14 June 1995 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics accomplished this SB under EO 217044 on 12 September 1997.
MD-11-33-054 "Modify/Replace emergency light battery pack." This SB was issued 27 March 1998 and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. There is no record in the SR Technics Status List of Engineering Orders of this SB being carried out.
MD-11-52-031 "Replace door exterior control switch and solenoid." This SB was issued 4 September 1996, revision R01 issued 20 October 1997, and is applicable by fuselage number effectivity to HB-IWF. Douglas Aircraft Company recommends accomplishment at the earliest practical maintenance period. SR Technics accomplished this SB under EO number 217153.01 on 12 September 1997.

Daily Technical Reports

As described in the SR Technics Reliability Program, Daily Technical Reports show all initial flight interruptions attributed to cancellations or technical delays exceeding 15 minutes.

The Daily Technical Reports from 1 January 1997 to 3 September 1998 for HB-IWF were reviewed:

  • On 3 August 1998 the right-hand DC bus tie sensing relay, relay base, and sockets had been replaced as a result of the failure of the relay. (Refer to "A08 check" review.)
  • On 11 March 1997 the galley load control unit was replaced after the galley buses 1 and 3 OFF light was found illuminated and could not be reset.

Pilot Complaints

All complaints documented in the aircraft logbooks are considered "Pilot Complaints." Each of these entries are categorized by ATA chapter and recorded in a database. The information is then statistically reported in the Monthly Reliability Report and is described as a ratio: number of complaints/1000 FH. Below is a sample of what Swissair reported, from September 1997 to September 1998:

Table: Swissair Reports September 1997 to September 1998

ATA Chapter Number of Complaints Ratio
24 - Electrical Power 154 1.86
25 - Equipment/Furnishing 6 131 74.01
31 - Instruments 275 3.32
33 - Lights 1 849 22.32

Note: As there are no industry standards for reporting most complaints and reporting disciplines vary from airline to airline, the number of complaints cannot be considered indicative of product quality.

Non-Routine Structural Maintenance from
Last "D Check"

The non-routine structural discrepancies from the last "D check" were reviewed; none were directly pertinent to the investigation.

Structural Significant Inspection Items from
Last "D Check"

The Structural Significant Items from the last "D check" were reviewed; none were directly pertinent to the investigation.

Time-Controlled Components

The "Time-Controlled Components" inventory list, dated 3 September 1998, was reviewed; there was nothing noted that was directly pertinent to the investigation.

The "Limit Exceeded Components" MD-11 fleet reliability list, September 1997 to August 1998, was reviewed; no significant deviations were noted.

A list of components that had a shop visit, but did not have previously recorded maintenance, was reviewed; no significant events or maintenance actions were noted.

Aircraft Technical Records

SR Technics provided the aircraft technical records, including such documents as the following:

  • Job cards, "A checks" (A02 - A12), "C checks" (C01 - C08), and the
    "D01 check;"
  • Aircraft logbooks (1996, 1997, 1998);
  • EO job cards;
  • Pre-flight checks; and
  • Repair cards.

These were reviewed by the investigation team.

Technical Logbooks

Note: As there are no industry standards for reporting, most logbook entries and reporting disciplines vary from airline to airline, and the number of entries cannot be considered indicative of product quality.

The aircraft technical logbooks used by Swissair were designed such that there were 25 pages, each with four Complaint/Action cards, starting at Seq Number 00. From 10 September 1997 to 2 September 1998 there were 2 663 entries recorded, including 790 for pre-flight checks. Each entry was reviewed to determine whether it was related to events that could cause chafing, arcing, sparking, smoke, or all in the cabin or cockpit, or was in the area of interest (cockpit and forward cabin ceiling area). There were no trends evident.

The following information was reviewed:

There was one entry that referred to an electric smell, the first class Hot Cup electric socket had burnt. The part was replaced and there were no further discrepancies noted.

  • 101 entries dealt with, or included the word, circuit breaker (CB, RCCB, etc);
  • 13 entries dealt with a "whistling" noise in the cockpit;
  • 10 entries dealt with activities that could be directly pertinent to the investigation;
  • 13 entries dealt with the fuel system; and
  • 9 entries dealt with the air supply system.

Although each "Complaint" had an "Action" recorded against it, there were a few entries that appeared to be outstanding. However, it was determined that this was attributable to discrepancies in the bookkeeping practices, rather than the entry not being rectified.

"A Check" Review

The last three "A checks" were reviewed to determine whether there were any maintenance activities directly pertinent to the investigation, such as events that could cause chafing, arcing, sparking, smoke, or all in the cabin or cockpit, and if any such event was in the area of priority (cockpit and forward cabin ceiling area). There were no activities identified in the "A06 check," 10 May 1998.

There was one scheduled activity identified in the "A07 check," 21 June 1998:

The air motor for the Left Forward (door 011) passenger door was changed, and to gain access to this motor the ceiling panel above the door must be moved prior to performing the maintenance activities.

There were two scheduled activities identified in the "A08 check," 9 August 1998:

The air motor for the Right Forward (door 021) passenger door was changed, and to gain access to this motor the ceiling panel above the door must be moved prior to performing the maintenance activities.

The cockpit zone temperature control sensor (ejector) was removed, cleaned and re-installed. This item is located above the ceiling, in the area adjacent to the cockpit entrance door. Access is through a ceiling panel.

There was one repair card generated and identified in the "A08 check," 9 August 1998:

A relay socket in the avionics compartment was changed as a result of damage.

The investigation team was also made aware of a report, by an M/C on an earlier HB-IWF flight, of an unusual smell. The accident aircraft's maintenance records were reviewed to confirm this report. Although not recorded in the aircraft technical logs, on 10 August 1998 the M/C reported to both the flight crew and ground crew that he noticed a burning/electrical smell specifically in the area around the 1.1 jumpseat (beside the L1 door), attached to the G1 galley. This report was made on the first flight following the completion of the "A08 check" in Zurich. A review of the "A08 check" maintenance requirements and of Bill Of Work 9838517, which was accomplished during the same maintenance period, did not reveal any maintenance activities that could be linked directly to a smell of this description.

The cargo for Hong Kong, located in compartment 2, included ethyl acetate solution, ethyl methyl ketone, printing ink, paint, and perfumery products. All of these items had Dangerous Goods declarations issued by the shipper, and there were no reported claims for damage.

IFEN System Maintenance Activity Review

All maintenance activities related to the IFEN installation were documented on a comprehensive database. There were 17 052 entries recorded for all the Swissair aircraft equipped with the IFEN system, covering the period from the first installation until system deactivation on 28 October 1998.

The collected data included, in part, aircraft registration, trouble, action, date A/C[1] in, and date A/C out. "Action" was the maintenance activity that addressed the initial "trouble." For the purpose of evaluation, entries were grouped into the following four categories:

  1. Reboot, including entries that made reference to a hard or soft reboot, system reset, or both;[2]
  2. Parts Replace, including all scheduled and non-scheduled parts replacements;
  3. Software Related, including all upgrades and re-installations;
  4. Maintenance Related, including entries such as "plug installed" and "plug replaced," and equipment repairs.

The following table shows a comparison between HB-IWF and a sampling of the other MD-11 aircraft with the same IFEN system configuration.

Table: IFEN System Configuration Comparison of HB-IWF with Other MD-11s

HB- C-Class Install Date F-Class Install Date Total Reboot Parts Replace Software Related Maintenance Related
IWF 9/97 2/98 620 412 149 23 36
IWI 10/97 10/97 527 258 193 36 40
IWE 4/97 3/98 844 500 271 34 39
IWC 12/97 12/97 629 385 162 14 68
IWK 1/98 1/98 581 361 184 26 10

Audits

SR Technics Internal Audit

To ensure all elements of the MOE were audited at least once a year, each QA department was to establish an audit plan for their assigned area and these plans were to be based on the audit master-plan. The audit master-plan was established by QA for one year in advance and was to be forwarded to the FOCA for their approval. Each audit performed was to be documented in an audit report that included

  • the order and scope of the audit;
  • the departments audited and the participants;
  • internal regulations relevant to the audit; and
  • findings and necessary corrective actions, if noncompliance with valid procedures were noticed.

Corrective actions were documented and their implementation was to be supervised by the relevant QA department. The audit reports were to be summarized and published in the company's quality report. QA also monitored trends in the field of QA and supported all departments in the development of measures to attain the required quality standards.

SR Technics provided a quarterly report summary of the results of 65 internal audits that were performed between 4 April 1997 and 13 July 1998. The main areas of discrepancies were summarized for each quarter and, although there were no specific findings, the summaries presented a pattern in which similar discrepancies were repeatedly identified. These included

  • deviations from SR Technics' internal policies and procedures, such as record-keeping requirements, sign-off procedures, and materials;
  • training requirements not defined, training records, and staff training plan; and
  • inventory and material control of parts and supplies.

A review of this internal audits summary did not identify any technical discrepancies that were considered directly pertinent to the investigation.

FOCA Audits

Prior to Swissair receiving its AOC on 31 March 1998, the FOCA ensured Swissair's compliance with the relevant regulations based on Swiss national law, using the internal directive "Rules Governing Flight Operation Inspections." The FOCA achieved this by conducting regularly scheduled meetings with various Swissair managers (e.g., flight operations, chief pilots, quality, flight safety), and by reviewing Swissair reports pertaining to flight safety and daily operations.

After 1 April 1998 the FOCA was to monitor Swissair's continued competence to conduct safe operations in compliance with JAR-OPS 1 regulation "Procedures for Assessing the Continued Competence of an AOC Holder." There is no record of the FOCA performing an audit of Swissair, in accordance with JAR-OPS 1 regulations, from 1 April to 2 September 1998.

SR Technics was a JAR-145-certified maintenance organization and the FOCA monitored it in accordance with the JAR requirements.

SR Technics' JAA and FAA approvals are based on compliance with regulatory requirements, and if procedures are not followed or standards upheld then both the FAA and the FOCA reserve the right to suspend, vary, or cancel their respective approvals of the organization.

To ensure SR Technics was in compliance with the JAR-145 maintenance organization requirements, the FOCA performed the following audits:

Table: FOCA Audits

Date Scope of Audit
11 November 1996 Aircraft Maintenance and Overhaul
18 December 1996 Powerplant
19 March 1997 Materials
26 August 1997 Components
3 September 1997 Engineering and Quality
23 April 1998 Human Resources
12 August 1998 Powerplant
20 October 1998 Aircraft Maintenance and Overhaul

A review of findings from these audits did not reveal any technical discrepancies directly pertinent to the investigation.

Corrective Actions

One of the purposes of an audit is to determine whether policies and procedures, directives, and specifications are properly implemented and maintained at all levels within the organization.

In accordance with the JAA requirements, SR Technics was to develop and put into effect a corrective action for each audit finding, and the FOCA was to assess the action and determine whether it was acceptable. The corrective actions undertaken by SR Technics, and accepted by the FOCA, focused on remedying the specific deficiency described in the finding. This pattern is apparent throughout subsequent audits, within various sections of SR Technics, in which similar deficiencies were repeatedly identified as findings. Examples include

  • storing serviceable aircraft parts with unserviceable, non-conforming, and non-aircraft parts;
  • deviations from manufacturers' instructions, such as surface treatments and repairs not in accordance with specifications;
  • deviations from SR Technics' internal policies and procedures, such as inconsistent identification of documents, internal audits not performed in accordance with procedures, and traceability of document records not consistent with published procedures; and
  • training requirements not defined, and continuation training not carried out.

[1]   "A/C" means aircraft.

[2]   "Reset" is defined as "causing a device to return to a former state." Therefore, when a tripped CB is pushed in, it is "reset." "Reboot" is defined as "to boot up a system again." Therefore, when a CB is deliberately pulled and then pushed in (i.e., cycled) it is done to "reboot" the system. Swissair and SR Technics personnel use the term "reboot" and "reset" interchangeably when they are referring to rebooting the IFEN system software. None of the "reboot" entries identified above are for a "reset" of a tripped CB.

Date modified :
2012-07-27