Narrative:

First officer was PF, highly experienced with advanced cockpits (large transport and medium large transport) and about 2 months experience on the medium large transport, was hand flying aircraft with automatic thrust active in the speed mode. Intercepted GS from above in landing confign and managed airspeed (FMS calculated). Engines were at flight idle because actual airspeed was higher than FMS approach speed. Automatic thrust was active and in the speed mode. Once GS was captured, airspeed bled off and went below approach speed and vls (FMS min speed). First officer looked at engine instruments to see what the engines were doing (thrust levers don't move with automatic thrust active) and there was no indication of them spooling. To maintain airspeed, he lowered nose and gave up following GS. He again checked engine instrument, brought up nose, again went below vls with no apparent response from automatic thrust. He again lowered nose to get back to vls and became puzzled with what to do with the thrust levers. We were now approximately 1000 ft AGL, fully configured, engines at idle and sinking 2000 FPM. Just prior to the first officer fire walling thrust levers, I took control of the aircraft, brought the thrust lever back to an intermediate position and disconnected automatic thrust. The engines spooled up, I leveled off and then captured GS from below and completed the approach. The nonmoving thrust levers are a terrible design which has contributed to at least 1 accident. I recommend: 1) when hand flying, automatic thrust on this aircraft must be off, ie, throttles are now conventional. This should be a limitation. 2) FAA should deny certification of any future aircraft without moving automatic throttles (ie, large transport). Airworthiness directive should also be issued to modify the medium large transport as well. I sent in a report to you regarding inadvertent rudder trim activation on the medium large transport 1 yr prior to the medium large transport accident at la guardia. But nothing was done and the rudder trim contributed to numerous deaths in that accident. Please don't overlook this problem. I am pro-technology but when 3 medium large transport's crash in its very short history, it makes a strong statement about the human interface with this technology, especially with the medium large transport/large transport long history of almost accident free flying as a comparison. It's not asking that much to put moving automatic throttles back into cockpits. Callback conversation with reporter revealed the following: the reporter very strongly believes that something must be done to fix this problem as he believes that at least 2 aircraft have crashed because of this design. He points out that none of the american made aircraft with automatic throttles have had this kind of problem. The reporter also believes that more training cannot be the whole answer to the problem, a design fix will be required, and the sooner the better.

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Original NASA ASRS Text

Title: THIS RPTR WATCHED HIS FO STRUGGLE WITH AUTO THROTTLES TO THE POINT THAT THE RPTR HAD TO TAKE THE ACFT AWAY FROM THE FO TO PREVENT A POSSIBLE CRASH.

Narrative: FO WAS PF, HIGHLY EXPERIENCED WITH ADVANCED COCKPITS (LGT AND MLG) AND ABOUT 2 MONTHS EXPERIENCE ON THE MLG, WAS HAND FLYING ACFT WITH AUTO THRUST ACTIVE IN THE SPD MODE. INTERCEPTED GS FROM ABOVE IN LNDG CONFIGN AND MANAGED AIRSPD (FMS CALCULATED). ENGS WERE AT FLT IDLE BECAUSE ACTUAL AIRSPD WAS HIGHER THAN FMS APCH SPD. AUTO THRUST WAS ACTIVE AND IN THE SPD MODE. ONCE GS WAS CAPTURED, AIRSPD BLED OFF AND WENT BELOW APCH SPD AND VLS (FMS MIN SPD). FO LOOKED AT ENG INSTS TO SEE WHAT THE ENGS WERE DOING (THRUST LEVERS DON'T MOVE WITH AUTO THRUST ACTIVE) AND THERE WAS NO INDICATION OF THEM SPOOLING. TO MAINTAIN AIRSPD, HE LOWERED NOSE AND GAVE UP FOLLOWING GS. HE AGAIN CHKED ENG INST, BROUGHT UP NOSE, AGAIN WENT BELOW VLS WITH NO APPARENT RESPONSE FROM AUTO THRUST. HE AGAIN LOWERED NOSE TO GET BACK TO VLS AND BECAME PUZZLED WITH WHAT TO DO WITH THE THRUST LEVERS. WE WERE NOW APPROX 1000 FT AGL, FULLY CONFIGURED, ENGS AT IDLE AND SINKING 2000 FPM. JUST PRIOR TO THE FO FIRE WALLING THRUST LEVERS, I TOOK CTL OF THE ACFT, BROUGHT THE THRUST LEVER BACK TO AN INTERMEDIATE POS AND DISCONNECTED AUTO THRUST. THE ENGS SPOOLED UP, I LEVELED OFF AND THEN CAPTURED GS FROM BELOW AND COMPLETED THE APCH. THE NONMOVING THRUST LEVERS ARE A TERRIBLE DESIGN WHICH HAS CONTRIBUTED TO AT LEAST 1 ACCIDENT. I RECOMMEND: 1) WHEN HAND FLYING, AUTO THRUST ON THIS ACFT MUST BE OFF, IE, THROTTLES ARE NOW CONVENTIONAL. THIS SHOULD BE A LIMITATION. 2) FAA SHOULD DENY CERTIFICATION OF ANY FUTURE ACFT WITHOUT MOVING AUTO THROTTLES (IE, LGT). AIRWORTHINESS DIRECTIVE SHOULD ALSO BE ISSUED TO MODIFY THE MLG AS WELL. I SENT IN A RPT TO YOU REGARDING INADVERTENT RUDDER TRIM ACTIVATION ON THE MLG 1 YR PRIOR TO THE MLG ACCIDENT AT LA GUARDIA. BUT NOTHING WAS DONE AND THE RUDDER TRIM CONTRIBUTED TO NUMEROUS DEATHS IN THAT ACCIDENT. PLEASE DON'T OVERLOOK THIS PROBLEM. I AM PRO-TECHNOLOGY BUT WHEN 3 MLG'S CRASH IN ITS VERY SHORT HISTORY, IT MAKES A STRONG STATEMENT ABOUT THE HUMAN INTERFACE WITH THIS TECHNOLOGY, ESPECIALLY WITH THE MLG/LGT LONG HISTORY OF ALMOST ACCIDENT FREE FLYING AS A COMPARISON. IT'S NOT ASKING THAT MUCH TO PUT MOVING AUTO THROTTLES BACK INTO COCKPITS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THE RPTR VERY STRONGLY BELIEVES THAT SOMETHING MUST BE DONE TO FIX THIS PROBLEM AS HE BELIEVES THAT AT LEAST 2 ACFT HAVE CRASHED BECAUSE OF THIS DESIGN. HE POINTS OUT THAT NONE OF THE AMERICAN MADE ACFT WITH AUTO THROTTLES HAVE HAD THIS KIND OF PROBLEM. THE RPTR ALSO BELIEVES THAT MORE TRAINING CANNOT BE THE WHOLE ANSWER TO THE PROBLEM, A DESIGN FIX WILL BE REQUIRED, AND THE SOONER THE BETTER.

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.