Aviation Investigation Report A98H0003

Communications

  1. External Communications
    1. JFK Ground Communications
    2. JFK In-Flight Communications
    3. Boston Communications
    4. Thirteen-Minute Communication Gap
  2. Internal Communications
    1. Interphone Call Procedures for Flight and Cabin Crew
    2. Cabin Crew Adherence to Interphone Call Procedures
    3. Communication and Co-ordination between Cabin and Flight Crew
  3. Other Communications
    1. SAR Communications
    2. Cellular Telephone and Satellite Communications
  4. Communications Procedures
    1. Compliance with Communication Procedures
      1. Control Actions and Radio Phraseology
      2. Control Clearances and Radio Phraseology
      3. Landing Information and Phraseology
      4. Altitude Clearances and Phraseology
      5. Radar Vectoring and Phraseology
      6. General Phraseology
    2. Fuel Dumping Procedures
    3. Emergency Response Actions and Communications
      1. Circumstances and Events of the Planned Fuel Dump
    4. Emergency Communications Terminology

External Communications

JFK Ground Communications

The SR 111 flight crew contacted Kennedy clearance delivery at 2336:48 and advised that they would be ready to start their engines in approximately 10 minutes. Kennedy clearance delivery immediately issued an ATC clearance to Geneva, Switzerland, which SR 111 read back. SR 111 was subsequently instructed to contact ground control for taxi clearance. Twenty-two minutes later, at 2359, SR 111 contacted ground control and advised that they were ready for taxi. After receiving progressive taxi instructions over the intervening six minutes, at 0005, the SR 111 flight crew was directed into the take-off queue on the Papa taxiway and advised to contact Kennedy control tower. At 0010, Kennedy tower advised SR 111 to anticipate a Papa Charlie intersection departure. At 0016:09, Kennedy tower issued a take-off clearance on Runway 13R from the Papa Charlie intersection. The Papa Charlie intersection is approximately 1 500 feet from the threshold of Runway 13R, leaving approximately 13 000 feet of runway available for take off.

(See map of "SR 111 taxi route at JFK.")

JFK In-Flight Communications

At 0017:04, SR 111 reported that it was beginning the take-off roll and was issued the wind direction and speed (180 degrees at 11 knots) by Kennedy tower. At 0018:47, SR 111 contacted Kennedy departure control and advised that they were on a heading 155 degrees as cleared. Kennedy departure control reported that the flight was identified on the radar (radar contact) and, at 0018:53, directed SR 111 to proceed directly to the BETTE intersection and to climb to 11 000 feet. There were numerous thunderstorms in the vicinity of New York at the time and, at 0019:46, while in the left turn toward the heading directly to the BETTE intersection, SR 111 requested to steer 120 degrees to avoid the weather. (STI) The deviation was approved and the aircraft remained on the 120 heading for seven miles before turning farther left to a heading of 103 degrees, directly to the BETTE intersection. The heading of 120 degrees rather than the direct heading (approximately 106 degrees) to the BETTE intersection, as cleared at 0018:53, permitted SR 111 to deviate approximately two miles further south than the direct route would have taken. At the time of SR 111's departure from JFK, there were several areas of heavy weather in the vicinity and several departures to the south and north were delayed or vectored to avoid thunderstorm cells. There were no reported deviations by flights departing along the route of flight followed by SR 111 in the direction of the BETTE intersection and Nantucket. At 0022:42, control of the flight was transferred to the Boston ARTCC on frequency 132.3 MHz.

Boston Communications

At 0022:42, the aircraft was transferred to the Boston ARTCC (Sardi sector controller) on frequency 132.3 MHz climbing to 11 000 feet. The Sardi sector controller issued a clearance to SR 111 to continue climbing to FL190 and subsequently transferred control to the next appropriate controller (Hampton sector) on frequency 124.52 MHz at 0028. The Hampton sector controller issued climb clearances to SR 111, as traffic allowed, to FL230 at 0028, FL240 at 0030:26, FL250 at 0031:56, and FL270 at 0032:56. The flight crew acknowledged each of these transmissions. At 0033:02, SR 111 was directed to contact the next Boston controller (Cape sector) on frequency 128.75 MHz. When SR 111 did not read back the assigned frequency, the controller repeated the assigned frequency. The flight crew acknowledged by reading back the correct frequency at 0033:12 and indicated that the aircraft was departing the current frequency.

Thirteen-Minute Communication Gap

From 0033:12 to 0046:27 (approximately 13 minutes), the Boston ARTCC Cape sector controller was unable to contact SR 111 on frequency 128.75 MHz despite making eight attempts to do so. At 0034:55, the Cape sector radar controller attempted to contact SR 111 to issue clearance to climb to FL310. No reply was received. At 0036:14, the Cape sector controller requested that the previous controller attempt to contact SR 111 again on the previously assigned frequency. The Cape sector controller was advised that there was no response. At 0039:02, the Cape sector controller again requested the previous controller to contact SR 111 and, at 0039:36, was advised that there was no response.

In an attempt to contact SR 111, the Cape sector radar associate controller reportedly requested that the Augusta sector controller, who was controlling Swissair 104, try to have that aircraft raise SR 111 on the Swissair company frequency. During this conversation, SR 111 made contact with the Augusta sector controller on frequency 134.95 MHz. The Augusta sector controller assigned frequency 133.45 MHz and SR 111 subsequently contacted the next Boston sector controller on that frequency. At 0052:32, the controller cleared the aircraft to climb to FL330, the flight-planned altitude.

Since the FDR does not record changes to VHF radio frequency selections, there is no indication of the frequency the pilot selected. At 0033:21 (13 seconds after the Boston ARTCC Cape sector controller's first attempt to contact SR 111), the FDR channel that records microphone keying indicated that the VHF radio was activated in the aircraft until 0033:25. This transmission was not recorded on any known ATC communications recording device and was not monitored or reported as having been heard by any ATC agency or aircraft.

At 0033:21, the FDR recorded that the VHF 1 radio was keyed for four seconds. This transmission was not recorded, monitored, or reported on or by any ATC communication device, ATC unit, or other aircraft. The FDR samples the status of the VHF transmission key once each second at the 203/1000 point of each second and indicates whether the radio is keyed at that sampling point. The timing of the VHF keying of the aircraft transmitter cannot be taken as an absolute indication that the transmission began at exactly 0033:21 and ended at 0033:24. During the sampling points of seconds 21, 22, 23, and 24, there is a record that the radio was keyed; the keying could, however, have begun a fraction of a second earlier during second 20 from 0033:20.204 or second 21, and ended a fraction of a second later during second 24 or second 25 up to 0033:25.202.

When establishing initial contact with a different controller, the content of Swissair's transmissions are generally similar in content and length. There are three other initial transmissions of similar length made by SR 111 for which transmission and keying data have been correlated: with Augusta sector at 0046:27, with Nantucket sector at 0047:45, and with Moncton ACC Tusky sector at 0058:13. The lengths of these transmissions were examined to determine whether the keying sequence at 0033:21 to 25 may have contained similar content. The transmissions indicated, respectively, three, three, and four seconds of keying activity. The similarity in initial transmission length may indicate that the Swissair transmission at 0033:21 was expected to be a normal initial transmission to the next Boston sector controller. It was, however, not received on the assigned frequency of 128.75 MHz.

FDR data indicate that SR 111 made 11 transmissions during this time, 9 on VHF 1, and 2 on VHF 2. At 0046:27, a transmission was recorded on Boston ARTCC recording devices on frequency 134.95 MHz (Augusta sector). At 0047:02, the FDR indicated another transmission, which was not recorded on the Boston ARTCC recording device. The Augusta sector controller then instructed SR 111 to contact Boston ARTCC Nantucket sector on frequency 133.45 MHz. At 0047:45, SR 111 contacted Boston ARTCC Nantucket sector on that frequency and normal communications resumed. During the 13-minute communication gap, the Boston ARTCC Cape sector controller attempted to contact SR 111 four times on frequency 128.75 MHz, three times on the original frequency (124.52 MHz), and as reported by the FAA, at least once on the aviation emergency frequency, 121.5 MHz. The times of the Swissair transmissions do not coincide with these attempts, indicating that SR 111, in its 11 transmissions, was not responding to these calls. No other aircraft reported hearing any SR 111 transmissions on the applicable frequencies and there was no report of communications difficulties with other aircraft in the vicinity. At 0038:29, the Boston ARTCC Cape sector controller requested SR 111 to squawk "ident" if the transmission was received. No "ident" squawk was observed on ATC radar. There are no discernable keying or transmission sounds on the ATC recording tapes to indicate that a carrier may have been transmitted without voice.

The FAA reported that the concerned controllers followed normal FAA NORDO operating procedure in their communications with SR 111.

At 0053:40, the Boston ARTCC Cape sector controller advised the Moncton ACC high en route controller of the impending transfer of several flights to Moncton's control, including SR 111. At 0058:03, SR 111 was advised to contact Moncton ACC on frequency 135.2 MHz.

Internal Communications

Interphone Call Procedures for Flight and Cabin Crew

Flight and cabin crew procedures for communicating using the interphone system were included in both the CEM and the AOM.

The CEM and the AOM include the following procedures for normal in-flight calls.

Table: Normal In-Flight Calls Procedures

From To Procedure Remarks
Cockpit Cabin Push applicable call button once. One single-stroke chime sounds at station being called.
Cabin Cockpit Push pilot call button once. One single-stroke chime sounds in cockpit.
Cabin Cabin Push applicable call button twice. Two single-stroke chimes sound at station being called.
Cabin Cockpit Push pilot call button for "open door." Two single-stroke chimes sound in cockpit.

The CEM and the AOM include the following procedures for urgency calls.

Table: Urgency Calls Procedures

From To Procedure Remarks
Cockpit Cabin Push all-stations button six times or more. Six single-stroke chimes sound at each flight attendant station. All cabin crew members must reply.
Cabin Cockpit Push pilot call button six times or more. Six single-stroke chimes sound in cockpit. Flight crew must reply. Any flight attendant can make an urgency call.

Urgency calls from the cockpit to the cabin can also be communicated using the PA system, for example, "MC report to the cockpit." Any flight attendant can report to the cockpit to communicate urgent information instead of using the interphone.

In all cases, crew members are required to identify themselves by name and to state the respective interphone station when initiating or receiving an interphone call. This procedure was not consistently followed by the SR 111 cabin crew. It was not uncommon for Swissair cabin crew members, as a group, to engage in normal in-flight interphone calls without identifying themselves and stating the respective interphone station.

Procedures for emergency communication from the cockpit to the cabin include specific announcements on the PA system. Procedures for emergency interphone calls from the cockpit to the cabin are the same as those for an urgency call from the cabin to the cockpit.

Canadian and American carriers do not require cabin crew to identify themselves and the respective interphone station for every interphone call. Although procedures vary, all carriers require that cabin crew members identify themselves and the respective interphone station during emergency calls from the cabin to the cockpit.

Based on the information available, it was determined that overall, the cabin crew of SR 111 performed their duties in accordance with prescribed procedures.

Cabin Crew Adherence to Interphone Call Procedures

Cabin crew members deviated from standard interphone call procedures in that they did not consistently identify themselves and state the respective station during all interphone calls. This behaviour was observed during calls made before and after the cabin crew were aware that there was a problem in the cockpit.

Deviation from interphone call procedures may have been influenced by several factors: cabin crew members recognized each others' voices and, therefore, did not identify themselves; they were aware of which crew members were assigned to which stations and, therefore, did not identify the respective station; and in some cases, they may have been able to see the person with whom they were speaking and, therefore, did not identify themselves or the respective station. Deviation from interphone call procedures during normal operations is not unique to the SR 111 cabin crew.

In this occurrence, deviating from the interphone call procedures did not result in any negative consequences.

Communication and Co-ordination between Cabin and Flight Crew

Within minutes of the flight crew detecting an abnormal odour in the cockpit, the cabin crew was contacted. A flight attendant was asked to come to the cockpit to provide a third opinion on the odour and to describe the cabin environment. This same flight attendant promptly briefed the M/C on the situation in the cockpit. The M/C quickly established communication with the flight crew using the interphone to get a briefing from the captain. The captain's briefing to the M/C was timely and relevant to the perceived situation. During the briefing, the M/C exhibited good communication skills. Within seconds of having been briefed by the captain, the M/C briefed the passengers using the PA system immediately thereafter. The M/C continued to communicate with the cabin crew using the interphone, collected pertinent information, and provided guidance as required.

Other Communications

SAR Communications

The ATC MANOPS article 624 defines the conditions under which an ACC shall advise an RCC of an aircraft in one of the three emergency phases: uncertainty, alert, or distress. Immediately after SR 111 made the Pan Pan call and accepted the suggestion that Halifax could be used for landing, this information was relayed to the ACC supervisor, Halifax Tower, and to the RCC.

Table: ATC MANOPS RCC Notification Procedures

ATC MANOPS Article Procedure
624.1 Inform the appropriate RCC of information regarding an IFR or CVFR aircraft that is in one of the following emergency phases:
(R)
624.1 Reference
Dissemination of Information; 623.
Notification of the Operator; 626.
Communication Search – General; 631.
  A. UNCERTAINTY PHASE if
  1. no communication has been received from an aircraft within 30 minutes after the time a position report should have been received;
  2. a flight plan has been filed and no arrival report has been received by the ACC within 60 minutes after the estimated arrival time last notified to, or estimated by the ACC, whichever is later;
  3. a flight itinerary has been filed and no arrival report has been received by the ACC within 24 hours after the time that the pilot indicated on the flight itinerary; or (N)
    624.1A.3. Note: A pilot wishing search and rescue action to be initiated in less than 24 hours will indicate this in the "other information" portion of the flight itinerary.
  B. ALERT PHASE if
  1. following the uncertainty phase, the communication search has failed to reveal any news of the aircraft; (R)
    624.1 B. 1. Reference: Unsuccessful Search; 634.
  2. an aircraft has been cleared to land and fails to land within five minutes after the estimated time of landing and communication has not been re-established with the aircraft; or
  3. information has been received that indicates that the operating efficiency of the aircraft has been impaired, but not to the extent that a forced landing is likely.
  C. DISTRESS PHASE if
  1. the fuel on board is considered to be exhausted or to be insufficient to enable the aircraft to reach safety;
  2. information is received that indicates that the operating efficiency of the aircraft has been impaired to the extent that a forced landing is likely; or
  3. information is received that the aircraft is about to make, or has made, a forced landing.
624.2 Include the following information, if available, in a notification to the RCC:
  1. A statement of the emergency phase that exists.
  2. Name of unit and person calling.
  3. Significant information from the flight plan, or flight itinerary, such as the following:
    1. Type of flight plan or flight itinerary
    2. Aircraft identification
    3. Type of aircraft
    4. Point of departure
    5. Destination aerodrome
    6. Actual time of departure
    7. True air speed
    8. Estimated time of arrival
    9. Alternate airport
    10. Transmitting and receiving frequencies
    11. Number of persons on board
    12. Pilot's name
    13. Time fuel expected to be expended
  4. Colour and distinctive markings of aircraft.
  5. Time last communication received, by whom, and frequency used.
  6. Last position report and how determined.
  7. Whether two-way communication is available.
624.3 Inform the RCC of any pertinent information that you subsequently receive.
624.4 Inform the RCC without delay when the emergency no longer exists.

In accordance with the ATC MANOPS, article 624.2, the following information was provided to the RCC.

Table: Information Provided to the RCC

Article 624.2 Information Requirement Time Information Provided
A. A statement of the emergency phase (uncertainty, alert, or distress) 0118:14
B. Name of unit and person calling 0118:02
C. Significant information from the flight plan, flight notification, or flight itinerary, including the following sample information:
  1. Type of flight plan, flight notification, or flight itinerary: N/A
  2. Aircraft identification: 0118:07
  3. Type of aircraft: 0118:09
  4. Point of departure: 0118:38
  5. Destination aerodrome: 0118:38
  6. Actual time of departure: N/A
  7. True air speed: N/A
  8. Estimated time of arrival: 0118:48
  9. Alternate airport: N/A
  10. Transmitting and receiving frequencies: N/A
  11. Number of persons on board: Not available
  12. Pilot's name: Not available
  13. Time fuel expected to be expended: Not available
D. Colour and distinctive markings of aircraft Not available
E. Time last communication received, by whom, and frequency used 0132:46
F. Last position report and how determined 0132:46, 0132:57, 0133:16
G. Whether two-way communication is available 0118:03
H. Any action taken by reporting office 0118:14

At 0133:15, the Moncton ACC, anticipating the need for SAR resources, contacted both CFB Greenwood and CFB Shearwater to determine whether either station had aircraft airborne or immediately available to conduct a search.

The first call to the Halifax RCC took place at 0118:00, approximately 13 minutes prior to the crash. After receiving the information from the ACC that the aircraft was no longer visible on radar, and in the absence of any information that the aircraft may have crashed on land, the RCC immediately began directing available shipping resources to the entrance of St. Margaret's Bay to search for evidence of the aircraft. Shortly thereafter, tasking orders were issued to the Search and Rescue Squadron at CFB Greenwood to launch aircraft to carry out the search for SR 111. (STI)

Table: Halifax RCC Activities

Time Action
0118 The Moncton ACC called the Halifax RCC to inform them that an MD-11 reported smoke in the cockpit and was diverting to Halifax.
0130 The Moncton ACC called the Halifax RCC to inform them that SR 111 was lost off radar approximately 40 nm southwest of Halifax.
0130-0140 The Halifax RCC called 14 Wing CFB Greenwood and initiated a base recall and tasked both primary SAR aircraft (Labrador and Hercules). The Halifax RCC also requested potential additional resources (Auroras, Challengers, medical staff, etc.).
0130-0140 The Halifax RCC called 12 Wing CFB Shearwater and initiated a base recall. The Halifax RCC also inquired about potential additional resources (Sea Kings, medical staff, etc.).
0138 The Halifax RCC called and tasked SAR lifeboat CCG Sambro.
0138 The Halifax RCC called Marine Traffic and Traffic Services Halifax to broadcast a Pan Pan on incident and look for vessels of opportunity.
0142 The Halifax RCC called the RCMP and informed them of the situation.
0144 The Halifax RCC called the Queen Elizabeth II Hospital and informed them of the situation and its potential consequences.

The RCC Halifax provided the following list of resources, tasking times, response times, and on-scene times for the initial SAR resources.

Table: SAR Resource Activities

Resource Tasking Time Response Time On-Scene Time
CCG Sambro 0138 0154 0251
Labrador 0130-0140 0225 0250
Hercules 0130-0140 0250 0315

Cellular Telephone and Satellite Communications

The investigation team examined whether any crew members or passengers may have conveyed any messages from SR 111 by methods other than normal ATC or company communications.

There were two methods by which individuals may have made contact with agencies or individuals outside of the aircraft: SATCOM telephone facilities provided by Swissair on board the MD-11 for the convenience of passengers, or cellular telephones carried and used by passengers. Cellular telephones could have been used over one of the two mobile service providers' cellular networks in eastern Canada.

The SATCOM service to which Swissair subscribes for passenger voice communications is provided by SITA. SITA provided information on satellite communications as recorded in their usage logs for HB-IWF (the occurrence aircraft) for the period prior to the accident. They summarized the log review as follows:

During 2330 UTC Sep 2nd and 0231 UTC Sep 3rd, no voice communication over SATCOM was recorded in our logs. This is also confirmed by Laurentides GES, which reported no alarms or any emergency distress calls during this time frame. As footnote, the last voice communication recorded for HB-IWF was placed on flight SR 102 at 15:25 UTC, on September 2nd, with an APC call of 10 min 15 sec long. So, SATCOM was working on HB-IWF.

SITA advised that, according to their data, there were no SATCOM telephone calls made from SR 111 during the flight. SITA's analysis of all SR 111 flights from 1 August to 2 September 1998 showed that this flight does not normally experience a large number of voice calls by either passengers or by crew members, likely because it is a night flight. From 1 August to 2 September 1998, there was SATCOM voice phone call activity on only 19 flight days totalling 70 calls, most of which took place near the end of the flight, on arrival in Switzerland. Therefore, it is likely that in the hour after take-off there were no attempts to use the satellite communications telephone service.

Maritime Telephone and Telegraph Company and Rogers/Cantel provide the mobile cellular telephone facilities in Nova Scotia and New Brunswick that might have been used by owners of cellular telephones on SR 111. Both companies provided records of the calls that were handled by their facilities in Nova Scotia on 2 September 1998 between 0100 and 0130. These records included both the phone number dialing and the phone number dialed. The RCMP provided the available information on the home and cell phone numbers of the passengers on board SR 111. There were no matches between the numbers recorded by the cellular service providers as having been called during the period and the known phone numbers of the passengers or relatives. There has been no report of persons having received calls from any cellular phone or from any passenger in the aircraft by any means.

Communications Procedures

Compliance with Communication Procedures

Control Actions and Radio Phraseology

The control actions taken by the controllers in their handling of SR 111 included

  • issuing control clearances to the aircraft with which to comply under its own navigation;
  • issuing clearances to descend; and
  • issuing radar vectors.

Control Clearances and Radio Phraseology

Table: ATC MANOPS Control Clearances and Radio Phraseology Procedures
ATC MANOPS Article Procedure
135.3 Issue a revised altimeter setting if the setting changes by 0.02 inches or more.
412.1 Issue clearance items, as appropriate, in the following order:
(N)(R)
  1. Prefix
  2. Aircraft identification
  3. Clearance limit
  4. SID
  5. Route
  6. Altitude
  7. Mach number
  8. Departure, en route, approach, or holding instructions
  9. Special instructions or information
  10. Traffic information
412.1 Note: It is important that an IFR clearance contain positive and concise data phrased in a consistent manner.
415.2C If amending both route and altitude, ensure that all applicable route and altitude restrictions remain in effect.
201.4 Identify the station calling and use the words "THIS IS" unless there is no likelihood of misunderstanding as to the source of the transmission.
215.2 You may omit the name and the function of the unit from a radio transmission provided
  1. the unit has been previously identified;
    215.2 A. Example: CANADIAN TWO FOUR SEVEN CHANGE TO MY FREQUENCY 128.5.
  2. only one function is being provided; and
  3. there is no likelihood of misunderstanding.
103.1 Use the phraseology contained in this manual whenever possible. If a situation arises for which phraseology is not provided:
  1. Use words and phrases from Appendix 1; and
  2. If words and phrases from Appendix 1 are not found to be suitable, use language that is clear and concise.

There were two situations in which clearances were issued to the aircraft with which ATS initially expected the aircraft to comply under its own navigation: upon the high en route controller's issuance of clearance for SR 111 to turn right to Boston and upon the controller's subsequent clearance of the aircraft to Halifax. Both clearances maintained the essential elements of destination, turn instructions, and altitude.

In issuing these clearances to Boston and to Halifax the controller did not, and in the circumstances was not required to, use the term "This is Moncton Centre" after the initial contact in accordance with the ATC MANOPS, article 215.2. The controller also used the approved terms "turn right" and "proceed" as directed in the ATC MANOPS, Appendix 1, when issuing clearance to SR 111 to begin the turn to Boston and proceed direct for the turn to Halifax. In both cases the controller monitored the actions of SR 111 on radar to ensure that the aircraft was responding as expected.

Landing Information and Phraseology

Landing information is required to be issued to arriving aircraft in accordance with the MANOPS articles below.

Table: ATC MANOPS Landing Information and Phraseology Procedures
ATC MANOPS Article Procedure
341.1 Issue landing information to arriving aircraft:
341.1 Note: Except for the current altimeter setting, you need not issue information that you know the aircraft has already received.
  1. on initial contact; or
  2. as soon as practicable.
341.1 B Note: Landing information should be issued in time to be of use to the pilot.
471.1 If direct controller pilot communications is used, issue landing information before or shortly after the descent clearance.
471.2 Include the following items, as appropriate, in landing information:
  1. Wind
  2. Visibility
  3. Ceiling
  4. Altimeter setting
  5. Pertinent remarks from the current weather report
  6. STAR, including STAR transition, or FMS arrival
  7. Runway in use
  8. Approach aid in use
  9. Pertinent airport conditions
471.3 You may use the term "CAVOK" if applicable.
471.4 Except for the altimeter setting, you need not issue information included in the current ATIS broadcast, provided the aircraft acknowledges receipt of the broadcast.
471.5 Issue an aircraft any subsequent information that may affect its descent, approach, or landing.

SR 111 received all of the information listed in the ATC MANOPS, article 471.2 from Speedbird 214, the high en route controller, and the Halifax terminal controller.

Altitude Clearances and Phraseology

Altitude clearances were issued by both the high en route controller and the Halifax terminal controller. When issuing altitude instructions, the ATC MANOPS directs controllers to use phraseology, for example:

  • MAINTAIN (altitude), or
  • CLIMB/DESCEND TO (altitude).

In all descent clearances except one, the controllers' radio phraseology complied with the directions in the ATC MANOPS. The single exception occurred when SR 111 was cleared to descend to 10 000 feet by the high en route controller; the context and the message, however, were clear and appeared to be understood by the SR 111 flight crew.

One other altitude-related clearance governed by the ATC MANOPS was issued by the Halifax terminal controller. At 0124:25, SR 111 requested permission to fly between 9 000 and 11 000 feet. The Halifax terminal controller issued clearance for a block altitude between 5 000 and 12 000 feet. The conditions under which a block altitude may be authorized are specified in the ATC MANOPS, article 432.5, and the conditions under which it may be requested are specified in article 432.2 C, which specifies that a request may be made based on icing, turbulence, or fuel considerations. The controller authorized the block, complying with the direction of the ATC MANOPS, article 601.2 A, which directs controllers to "...provide as much assistance as possible to the aircraft in distress."

Radar Vectoring and Phraseology

The ATC MANOPS, Part 5, "Radar Procedures," provides direction to controllers on the procedures and phraseology to be used when providing radar vectors to aircraft.

Table: ATC MANOPS Radar Vectoring and Phraseology Procedures
ATC MANOPS Article Procedure
541.2 Vector an aircraft if
  1. necessary for separation purposes;
  2. required by noise abatement procedures;
  3. you or the aircraft will gain an operational advantage; or
  4. the aircraft requests it.
541.3 If you initiate vectoring, inform the aircraft of (P)
  1. the purpose of vectors; and
  2. the fix, airway, or point to which the aircraft is being vectored.
541.3 Phraseology:
VECTOR TO (fix or airway).
VECTOR TO INTERCEPT (name of NAVAID) (specified) RADIAL/COURSE.
VECTOR TO FINAL APPROACH COURSE.
VECTOR TO RUNWAY (number) TRAFFIC CIRCUIT.
545.1 Inform an aircraft of its position when
  1. identification is established by an identifying turn;
  2. vectoring is terminated;
  3. the aircraft requests the information;
  4. at least once, before commencing final approach; or (P)(N)
    545.1D Phraseology: (Number) MILES (direction) FROM (fix) DISTANCE TO THRESHOLD IS (number) MILES.
    545.1D Note 1: The distance to fly to the threshold should be included with the last position report before starting final approach.
  5. you deem it necessary.
545.2 Describe the position of an aircraft in relation to a fix, airway, course, or radial that is indicated on the radar display. (P)
545.2 Phraseology:
OVER/PASSING (FIX).
(Number) MILES (direction) OF (fix).
(Name of NAVAID) (specified) RADIAL IS (number) MILES TO YOUR LEFT/RIGHT INTERCEPTING/CROSSING (name of NAVAID) (specified) RADIAL.
CROSSING/JOINING/DEPARTING (airway).

The Halifax terminal controller issued radar vectors to SR 111 on three occasions: at 0119:28, at 0119:57, and at 0122:01. Each time, the controller provided the heading for the aircraft to fly in accordance with the ATC MANOPS, article 543.1 B, and the purpose for the vector either in the same transmission or shortly before or after.

The Halifax terminal controller issued radar position information on three occasions: at 0119:37, at 0122:01, and at 0123:53. In the first position report the controller specified the distance from the threshold as directed in the ATC MANOPS, article 545.1 D, using the basic phraseology recommended: "DISTANCE FROM THE THRESHOLD IS (number) MILES." The controller stated that he anticipated that the aircraft would continue straight in to landing.

The position reports issued at 0122:01 and at 0123:53 in accordance with the ATC MANOPS, article 545.1 E, were not mandatory reports. They were provided solely as an update on the changing distance as the aircraft was vectored for descent and to set up for the fuel dump. The position of the aircraft in relation to a fix, airway, course, or radial that is indicated on the radar display was not included, however, as required in article 545.2. This omission was of no significance.

General Phraseology

Nav Canada's internal Air Traffic Services Safety Bulletin, Squawk 7700, issue 9801, noted the following:

  1. The effectiveness of information transfer is highly dependent upon the use of standard phraseology, and given the widespread deviations from prescribed phraseology identified by Fact Finding Boards, clearly more emphasis on standard phraseology is required.
  2. Effective verbal communications is an essential element of safety in the aviation system. The proper use of the communications principles become increasingly important when air traffic services deals with foreign air carriers whose crews may not be fluent in the English language. Proper speech rate, tone and enunciation, coupled with the use of standard ATC terminology and control procedures help to reduce the risk of misunderstanding between controllers and flight crews.
  3. No other essential activity in Air Traffic Control is as vulnerable to failure through human error and performance limitations as spoken communication. Current approved Radio Telephony Communications were developed as a result of years of experience to reduce the potential for conflict. Unfortunately, use of non-standard terminology and poor read back/hear back practices continue to result in numerous operating irregularities.

Comparison of the transcript of the ATC transmissions with the recommended phraseology in the ATC MANOPS indicated a few instances of omissions, substitutions, excessive verbiage, and dysfluencies (pauses, stammers, or utterances that add no meaning to the message). There were no indications that any of the advisories, clearances, or requests made by ATC, regardless of phraseology used, were misunderstood, overlooked, disregarded, or ignored by the SR 111 flight crew.

Fuel Dumping Procedures

Fuel Dumping procedures for Nav Canada air traffic controllers are provided in the Nav Canada ATC MANOPS, Part 7, Section 701.

Table: ATC MANOPS Fuel Dumping Procedures
ATC MANOPS Article Procedure
701.1 If information is received that an aircraft plans to dump fuel, obtain the following information:
  1. The proposed track to be flown
  2. The period of time involved
  3. The weather conditions in which the operation will be carried out
701.2 You may request an aircraft to fly a different track.
701.3 You should encourage an aircraft intending to dump fuel, to do so:
  1. on a constant heading;
  2. over an unpopulated area; and
  3. clear of heavy traffic areas.
701.4 Restrict the aircraft dumping fuel to an altitude 2 000 feet or more above the highest obstacle within a horizontal distance of 5 miles of the track to be flown. Consider company operating requirements and, if necessary, consult with the aircraft to determine an appropriate altitude.
701.6 Arrange for a warning to be broadcast, at 3 minute intervals, beginning at a reasonable time before fuel dumping begins and continuing until 15 minutes after fuel dumping is completed, on:
  1. all appropriate ATC frequencies;
  2. all appropriate NAVAIDs; and
  3. air carrier frequencies if you consider it necessary.
701.7 Arrange for a notice of completion to be broadcast at the end of the warning period.

Further detailed fuel dump information for Moncton controllers is contained in the Moncton ACC Operations Manual (07-98), Part 3.20.

Table: Moncton ACC Operations Manual (07-98) Fuel Dumping Procedures
Article Procedure
3.20.1 Unless otherwise requested, direct aircraft dumping fuel in the HT/HZ Sector to an area between the 120 and 160 radials of CYHZ.
3.20.2 Information on fuel dumping must be passed to the FSS responsible for the area of responsibility within which the fuel dump will occur.
3.20.3 If a fuel dump is taking place in close proximity to an airport served by another FSS, or near an area of responsibility boundary, notification must be given to the all appropriate FSSs.
3.20.3 Note: Flight Service Stations generally do not have the capability to broadcast on NAVAID frequencies; they will broadcast on the appropriate en route frequencies, in accordance with their MANOPS.

Additional general information on fuel dumping is contained in the Transport Canada document TP2300, Aeronautical Information Publication, Part 6, "Rules of the Air and Air Traffic Services." Part 6.3.4 advises that "...aircraft will be encouraged to dump fuel on a constant heading over unpopulated areas and clear of heavy traffic."

The ATC MANOPS and the Moncton ACC Operations Manual (07-98) require that, during fuel dumping, warnings to all aircraft be transmitted on the frequencies listed in the ATC MANOPS, article 701.6. The required advisory to the Halifax FSS in accordance with these directives was passed between 0124:28 and 0125:29 by the low-level supervisor assisting in the coordination activities.

Emergency Response Actions and Communications

The ATC MANOPS, article 601, provides general directions to controllers to handle emergency situations.

Immediately after SR 111 transmitted the Pan Pan message and indicated that there was smoke in the cockpit, the high en route controller advised the high en route supervisor. At 0116:05, approximately 29 seconds after SR 111 advised that the aircraft would divert to Halifax, the Halifax International Airport Control Tower was advised of the proposed inbound aircraft. At 0118:02, Moncton ACC advised the Halifax RCC of the urgent situation and the proposed diversion and promised to keep the RCC advised. At 0120, Halifax Tower requested the AFF to take standby positions in anticipation of SR 111 landing within 10 minutes.

At 0120:37, ACC requested Halifax Tower to have the AFF standing by and was advised that they were already in position. At 0124:36, the low-level supervisor advised Halifax FSS that there was a fuel dump in progress, in anticipation that FSS would perform the advisory duties required to warn aircraft in the vicinity. At 0132:39, approximately two minutes after the last radar return from SR 111, Moncton ACC advised RCC that they had lost radar contact with the aircraft but were waiting for it to re-appear. At 0133:15, Moncton ACC called CFB Greenwood and CFB Shearwater seeking information on available SAR resources.

Though SR 111 did not declare an emergency until 0124:42, communications priority was given to the aircraft throughout the sequence of events; the aircraft was treated as if it had initially made a distress call (Mayday) rather than an urgency declaration (Pan Pan). Controllers are instructed to perceive the declaration of intent to dump fuel as an emergency situation.

By allocating one controller and one frequency to meet the communications needs of SR 111 on approach to Halifax, Moncton ACC complied with the request inherent in a Pan Pan declaration to provide communications priority.

Circumstances and Events of the Planned Fuel Dump

The first notification that SR 111 needed to dump fuel was received by ATC at 0121:27 when the MD-11 was established on a northbound track, which was initially intended as a short transition track following the request of the pilot for more than 30 nm before landing. The designated fuel dump area for Halifax is between the 120- and the 160-degree radials of the Halifax VOR. The aircraft was high enough to meet the designated fuel dump altitude requirements. Rather than take the aircraft off track, the controller concluded that St. Margaret's Bay was

  • the closest unpopulated area over which a constant track could be maintained for a significant period of time;
  • within 35 to 40 nm of the Halifax airport; and
  • still sufficiently convenient that on completion of the fuel dump the aircraft would be in a position to turn to a base leg for Runway 06 at Halifax.

Emergency Communications Terminology

Transport Canada's Aeronautical Information Publication, Part 6, "Rules of the Air and Air Traffic Services (RAC)", article 6.3.1, "Declaration of Emergency," provides the following information to pilots:

Whenever pilots are faced with an emergency situation, ATC expects the pilot to take whatever action is considered necessary. ATC will assist pilots in any way possible whenever an emergency is declared. Pilots are requested to advise ATC as soon as it is practicable, of any deviations from IFR altitudes or route necessitated by an emergency situation in order that every effort can be made to minimize confliction with other aircraft.

Air traffic controllers are required to comply with directives contained in the Nav Canada ATC MANOPS, Part 6, "Emergencies," and specifically Part 601.

Table: ATC MANOPS Emergency Communications Procedures
ATC MANOPS Article Procedure
601.1 Use the rules and procedures contained in this part as the basis for handling emergencies. (N)
601.1 Note: It is impossible to detail procedures for all emergency situations because of the many different circumstances that may arise. You are expected to use your best judgment in handling a situation not specifically covered.
601.2 During an emergency:
  1. provide as much assistance as possible to the aircraft in distress; (N)
  2. enlist the aid of all available facilities and services; and
  3. coordinate fully and completely with all concerned agencies.
601.2 A. Note: To assist flight crews in coping with an emergency, controllers must inform the crew of all pertinent information. The information should be accurate, to leave no doubt with the crew, concerning the situation taking place.
Date modified :
2012-07-27