Advanced Technology Aircraft Safety Survey Report - Australian ...

ADVANCED TECHNOLOGY AIRCRAFT SAFETY SURVEY REPORT
50
Table B3.9.3
Nominated phase of flight in which difficulty was encountered
Phase of Flight Response
Descent 44%
Approach (precision) 18%
Go Around 16%
Approach (non-precision} 9%
Other 1 0%
These results are of concern as the majority of accidents have been shown to occur during the
final approach and landing phases of flight. As can be seen from table 3.9.3, descent and
approach were the phases of flight in which most mode difficulties occurred.
Conclusion
A thorough theoretical and practical understanding of mode function is essential for the pilot
of a modern automated aircraft. This was highlighted in the report concerning the accident
involving an A300B4-622R aircraft at Nagoya, Japan, in 1994 (Aircraft Accident Investigation
Commission 1996), which listed the following as two of the twelve causes of the accident:
(2) The crew engaged the autopilot while go-around mode was still engaged, and continued
the approach; and
(6) The captain and first officer did not sufficiently understand the flight director mode
change and the autopilot override function.
Survey results presented in this chapter have revealed various inadequacies in both aircraft
design and training.
Over 30% of respondents reported that mode changes could occur without adequate
indication. Aircraft manufacturers need to ensure that mode changes (especially automatic
mode transitions) are adequately annunciated. Preferably, mode changes should be
accompanied by a discrete audible tone.
Mode selection is an important aspect of controlling an automated aircraft. A comprehensive
understanding of mode selection, mode function and the consequences of inappropriate
mode selection are required by the crew. Traditionally, pilots have been required to obtain a
100% pass in the fuel, and weight and balance sections of the type-rating examinations.
Failure to uplift sufficient fuel, or the incorrect loading of an aircraft, is potentially disastrous.
Similarly, a lack of knowledge regarding mode usage is equally dangerous. Mode operation
(both practical and theoretical) should be considered as important as fuel and loading
calculations for a modern automated aircraft.
Some airlines do not set clear guidelines and procedures when it comes to mode selection.
They view the setting of guidelines as contradicting the freedom of the operating pilot to use
an appropriate mode for the in-flight situation. There are two important issues here. The first
includes the recognition that guidelines, rules or policies are valuable aids to the pilot,
especially when newly endorsed on type. The second includes the importance of a consistent
policy which flows from the initial simulator training through to line operations. Similarly, it
would appear that briefings could be improved by including the intended use of modes during
any given phase of flight.
The written responses to question B3.9 (‘Please outline the details of a specific event where
you had difficulty with Mode Selection, Mode Awareness or Mode Transition’) provide a