Narrative:

Level FL350, first officer flying, I was in the back. He was given the following clearance: 'after arero, cleared direct delta intersection and hold, reduce to minimum speed at this time.' the first officer selected altitude hold and 240 KTS, then the throttles came to idle. Shortly after he got a chime, master caution and the following ECAM 'engine trim fault, select engine trim off' which he did. On resetting the engine trim, he noticed the airspeed was below the hook. He manually put the throttles to firewall power. As the airspeed was still decreasing, he disconnected the autoplt and started a gradual descent to get the airspeed back to green DOT. I returned to the cockpit as the airspeed was approaching green DOT, with approximately 700 ft altitude loss. I called hkg ATC requesting a descent to a lower altitude, but was told to maintain altitude. By this time the first officer was climbing back to FL350. Contributing factors: 1) the throttles were at idle when the engine trim fault happened. 2) the autothrottles tripped off, also, so did not capture the speed selected. Suggestion: have a status ECAM, after you reset the engine trim, stating the autothrottles are off.

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Original NASA ASRS Text

Title: AN A300-600 LOSES ALT WHEN THE AUTOTHROTTLE SYS MALFUNCTIONS. THE FO PF WAS UNAWARE THAT THE AUTOTHROTTLES HAD DISENGAGED AFTER AN ENG TRIM SYS WARNING ON THE ECAM.

Narrative: LEVEL FL350, FO FLYING, I WAS IN THE BACK. HE WAS GIVEN THE FOLLOWING CLRNC: 'AFTER ARERO, CLRED DIRECT DELTA INTXN AND HOLD, REDUCE TO MINIMUM SPD AT THIS TIME.' THE FO SELECTED ALT HOLD AND 240 KTS, THEN THE THROTTLES CAME TO IDLE. SHORTLY AFTER HE GOT A CHIME, MASTER CAUTION AND THE FOLLOWING ECAM 'ENG TRIM FAULT, SELECT ENG TRIM OFF' WHICH HE DID. ON RESETTING THE ENG TRIM, HE NOTICED THE AIRSPD WAS BELOW THE HOOK. HE MANUALLY PUT THE THROTTLES TO FIREWALL PWR. AS THE AIRSPD WAS STILL DECREASING, HE DISCONNECTED THE AUTOPLT AND STARTED A GRADUAL DSCNT TO GET THE AIRSPD BACK TO GREEN DOT. I RETURNED TO THE COCKPIT AS THE AIRSPD WAS APCHING GREEN DOT, WITH APPROX 700 FT ALT LOSS. I CALLED HKG ATC REQUESTING A DSCNT TO A LOWER ALT, BUT WAS TOLD TO MAINTAIN ALT. BY THIS TIME THE FO WAS CLBING BACK TO FL350. CONTRIBUTING FACTORS: 1) THE THROTTLES WERE AT IDLE WHEN THE ENG TRIM FAULT HAPPENED. 2) THE AUTOTHROTTLES TRIPPED OFF, ALSO, SO DID NOT CAPTURE THE SPD SELECTED. SUGGESTION: HAVE A STATUS ECAM, AFTER YOU RESET THE ENG TRIM, STATING THE AUTOTHROTTLES ARE OFF.

Data retrieved from NASA's ASRS site as of July 2007 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.