Telex Sent To A330/340 Operators Recommends Checking Airspeed
Indications Before Engaging Autopilot
A telex message sent by Airbus to companies operating A330 and
A340 aircraft seems to acknowledge a problem with the airspeed
sensors on the aircraft.
The telex, which was sent to ANN by a reader and which is also
published in the French newspaper Le Figaro, cautions flight crews
to check airspeed indications before engaging the autopilot, when
in alternate law.
The complete text of the telex reads:
FROM : AIRBUS CUSTOMER SERVICES TOULOUSE
TO : ALL A330/A340 CFM GE PW RR OPERATORS
FLIGHT OPERATIONS TELEX - FLIGHT OPERATIONS TELEX
OUR REF. : 999.0112/10 dated 20 December 2010
Subject: ATA 22 and 34 - Loss of AP and A/THR associated with
alternate law reversion
Notice: This FOT provides information about a significant
operational issue that is related to airworthiness or safety. It is
each Operator´s responsibility to distribute this FOT or to
distribute the information contained in this FOT, to all of their
applicable flight crews without delay. Failure to apply this FOT
may have a significant impact on safe aircraft operations. This FOT
and the OEB advance copies will be available in pdf format in
AirbusWorld within two days.
The purpose of this FOT is to recommend the flight crew to check
airspeed indications before engaging the autopilot, when in
When there are significant differences between all airspeed
sources, the flight controls revert to alternate law, the autopilot
(AP) and the autothrust (A/THR) automatically disconnect, and the
Flight Directors (FD) bars are automatically removed. It has been
identified that, after such an event, if two airspeed sources
become similar while still erroneous, the flight guidance
- Display FD bars again.
- Enable autopilot and autothrust re-engagement.
However, in some cases, the autopilot orders may be
inappropriate, such as possible abrupt pitch command. Therefore,
the flight crew must apply the following procedure.
3. OPERATIONAL RECOMMENDATIONS
When autopilot and autothrust are automatically disconnected and
flight controls have reverted to alternate law:
- Do not engage the AP and the A/THR, even if FD bars have
- Do not follow the FD orders
- ALL SPEED
If unreliable speed indication is suspected:
UNRELIABLE SPEED INDIC/ADR CHECK PROC...........APPLY
If at least two ADRs provide reliable speed indication for at
least 30 seconds, and the aircraft is stabilised on the intended
AP/FD and A/THR ......................................As
4. CORRECTIVE ACTION
This procedure will be cancelled by the next FCPC standards that
will be available before end 2011. This modification will inhibit
autopilot engagement in the above described situation.
For A330 aircraft, these operational recommendations will be issued
by beginning of January 2011 in red OEB 82/1 and its associated OEB
PROC 82/1 in the QRH. For A340-200/-300 aircraft, these operational
recommendations will be issued beginning of January 2011 in red OEB
95/1 and its associated OEB PROC 95/1 in the QRH.
No specific follow-up to this FOT is planned.