Aviation Investigation Report A98H0003
4.1.9 Standby Instrumentation
- 18.104.22.168 - Transportation Safety Board of Canada
- 22.214.171.124 - Swissair
- 126.96.36.199 - United States Federal Aviation Administration
- 188.8.131.52 - The Boeing Company
The investigation revealed that, as the SR 111 emergency progressed, various systems-related failures occurred that affected primary instrument displays and that standby instruments were being used. Given the substantially increased pilot workload during the emergency, the investigation became interested in the adequacy of the standby instrumentation. The results of TSB's inquiry indicated that when pilots have been forced to rely on standby instruments in emergency situations, they have noted deficiencies, including poor instrument location, small displays, difficulty in transition from primary flight instruments, and lack of adequate training.
It was determined that, while the Swissair MD-11 standby instruments meet regulatory requirements, their functionality may not be optimized. Limitations with respect to location, powering, and pilot training resulted in the TSB issuing two ASAs (A010042-1 (STI4-26) and A010042-2 (STI4-27)) on 28 September 2001. The advisories suggested that authorities consider reviewing the existing requirements for standby instrumentation, including related issues such as standby communication and navigation capabilities. The advisories also called for a review of present regulations and practices to ensure that flight crews receive adequate training in the use of standby flight instruments and that design standards be adequate to ensure that standby instruments are grouped adjacent to one another, and have a layout similar to the primary flight instruments.
As part of its "MD-11 Modification Plus" program, Swissair chose to install a secondary flight display system that has a layout similar to the primary flight display in the MD-11 aircraft. The display system includes attitude, airspeed, altitude, and heading in a single integrated display. In addition, in the event of a loss of primary aircraft electrical power to the unit, the display has an auxiliary battery that can supply power for a minimum of 45 minutes.
The FAA plans to address the emergency instrumentation issues raised by the TSB at the appropriate Aviation Rulemaking Advisory Committee (ARAC). This forum will compare the issues raised by the TSB with current safety issues and will decide upon a course of action.
Boeing advises that they have reviewed their current standby instrumentation equipment in an effort to identify any areas that could be optimized. As part of its ongoing product improvement effort to its customers, Boeing offers standby instrument systems, such as their Integrated Standby Instrument System used on the B-717, that combine several standby instrumentation requirements in a single display.
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