RECOMMENDED ACTIONS. :-
1) Since flight has to be continued without Auto Pilot /Flight Director and Yaw Dampers, descend to lower altitude depending on weight to give sufficient margin from MMO/ VMO and VLS, typically FL 290 /310.
2) Fuel forward transfer for better stability.
3) FMS will be available and will be dependant only on the remaining IRS. However as a backup and cross check, use the procedure as given in dual FMS failure for cross checking position at each waypoint and if on-track VOR is available use it to refine position.
4) Manual flying at high altitude requires caution and alertness for deviation from flight path. In addition you have to be very gentle otherwise it can be very unpleasant for the passengers especially in the rear cabin. It is recommended to use the FPV for all flight phases. A steady descent / climb can be maintained by keeping the bird in the" cage" after selecting the required descent / climb angle. Plan an early slow rate of descent commencing with an FPV angle of 20. Anticipate level off and reset the FPV angle to 00. Remember that the ILS will have to be carried out RAW DATA. The prescribed minima does not cater for complete Auto Pilot / Flight Director failure and therefore in marginal weather conditions close to minima it wold be advisable to inform ATC and divert.
INSTRUMENT FAILURE
Instrument failures can occur at any phase of flight, especially during very high icing conditions, volcanic ash encounters, etc. However failures which occur most unexpectedly and in a very crucial phase of flight are during or after take off and these have led to serious accidents.
Due to redundancy, triple IRS failure is not even catered for in the emergency/ abnormal checklist and the number of instruments / equipment failing in such a case can be visualized. In airline operations such an incident occurred. During the take off, a foreign object struck the fuselage behind the nosewheel with such a force that the limits of the IRS was exceeded. As a result all three of them failed.
In all cases of instrument failures there is no need to panic, overreact or hurry to hand over control or switch instruments. For example the detection of both standby ASIs failure above 100 kts is not a cause for rejection when the airspeed is available on the PFD. The first action should be to continue flying the aircraft and shift to the standby instruments namely the standby ASI and the standby horizon. Both these are on opposite sides of the instrument panel for the Captain, and requires a considerable scan. Do not be so preoccupied as to forget the flight path or SID.
To avoid disorientation / loss of control of aircraft due to incorrect recognition or incorrect switching of instruments, the basic philosophy for any instrument failure is as follows:
1. Control of aircraft with available/standby instruments. 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：Airbus ABNORMAL/EMERGENCY PROCEDURES 空客非正常/緊急程序(22)
