An A330 crew was distracted while dealing with an air conditioning system malfunction. There was a t...

Narrative:

On climb-out; aircraft was vectored off the SID and given a 350 heading and a climb to FL350. The heading and altitude were set in the FCU and verified on the FMA by the captain and first officer. This heading closely paralleled the SID. Later; during the climb; it was noted that the air conditioning system was sending below freezing air to the cabin. As the captain worked the problem; and the new first officer helped and accomplished his other duties; the aircraft somehow reverted to the navigation mode. This resulted in a turn to the right. The crew and ATC noticed the turn at about 010 degrees and an immediate correction was made. This aircraft was dispatched with two MEL's on the air conditioning system. Somehow the combination made temperature control problematic and the distraction contributed to the delayed recognition of the turn. While I am still not sure why the aircraft reverted to the navigation mode; it should have been recognized sooner. I needed to remember the cardinal rule of one pilot flying the aircraft exclusively and the other working the problem. Secondarily; the compound MEL's led to a distraction during a busy phase of flight. This contributed to the delayed recognition. These MEL's had existed for three and seven days each and the aircraft had transited maintenance stations multiple times. Although legal; MEL's that could cause distractions should be repaired in a timelier manner.

Original NASA ASRS Text

Title: An A330 crew was distracted while dealing with an air conditioning system malfunction. There was a track deviation after the FMGC reverted from a heading mode to the NAV mode.

Narrative: On climb-out; aircraft was vectored off the SID and given a 350 heading and a climb to FL350. The heading and altitude were set in the FCU and verified on the FMA by the Captain and First Officer. This heading closely paralleled the SID. Later; during the climb; it was noted that the air conditioning system was sending below freezing air to the cabin. As the Captain worked the problem; and the new First Officer helped and accomplished his other duties; the aircraft somehow reverted to the navigation mode. This resulted in a turn to the right. The crew and ATC noticed the turn at about 010 degrees and an immediate correction was made. This aircraft was dispatched with two MEL's on the air conditioning system. Somehow the combination made temperature control problematic and the distraction contributed to the delayed recognition of the turn. While I am still not sure why the aircraft reverted to the NAV mode; it should have been recognized sooner. I needed to remember the cardinal rule of one pilot flying the aircraft exclusively and the other working the problem. Secondarily; the compound MEL's led to a distraction during a busy phase of flight. This contributed to the delayed recognition. These MEL's had existed for three and seven days each and the aircraft had transited Maintenance stations multiple times. Although legal; MEL's that could cause distractions should be repaired in a timelier manner.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	968299
Time
Date	201109
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	A330
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Aircraft Auto Temperature System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer
Experience	Flight Crew Last 90 Days 175 Flight Crew Total 23500 Flight Crew Type 755
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

An A330 crew was distracted while dealing with an air conditioning system malfunction. There was a track deviation after the FMGC reverted from a heading mode to the navigation mode.