A B757-200. On initial climb at 1500 ft, the aircraft would not accelerate beyond 160 KTS in VNAV mo...

Attributes
ACN	534807
Time
Date	200201
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 1500
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sna.tower
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	534807
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : auto throttle speed ctl. other flight crewa other flight crewb
Resolutory Action	aircraft : automation overrode flight crew flight crew : overcame equipment problem
Consequence	other other
Supplementary
Problem Areas	Chart Or Publication Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

This incident occurred on climb out from ZZZ. Predep SOP's were followed. The departure was briefed twice since I am relatively new to the B757 and the first officer had not been to ZZZ in some time. Takeoff roll was normal. We were very light (184000 pounds). Rotation was normal. Gear was raised. Pitch was approximately 21-22 degrees, somewhat less than I expected based on our weight. At 800 ft VNAV was selected and pitch was reduced to 9-10 degrees. Again, less than the 12-13 degrees I anticipated to maintain V2 +15 KTS. At 1500 ft, the internal speed bug increased to 160 KTS. Airspeed was increased and flaps 1 degree were selected. The aircraft would not accelerate beyond 160 KTS and we could not climb. We agreed this was not normal, abandoned reduced climb, and selected normal climb. This did not help. The throttles came back to idle. I started a descent to maintain airspeed while pressing the throttle-disconnect button and attempting to manually push up the throttles. Initially, this did not work either. The throttles still tried to come back. A second attempt to press the throttle-disconnect button, holding it for a couple of seconds while pushing the throttles up, was successful. However, by that time we had lost 500 ft and had gotten a sink alert. The problem corrected the aircraft accelerated normally. A maintenance report was filed. Callback conversation with reporter revealed the following information: the reporter stated the FMS was programmed correctly and the autothrottle system and autoplt were operational with no open reports. The reporter said no report from maintenance was received by the crew on the failure of the autothrottle system to increase the speed after flap retraction and the failure of the autothrottle disconnect switch. The reporter stated when maintenance was contacted he was told the incident was closed. The reporter said the aircraft was returned to service and it was hinted the company believed the incident was caused by crew error.

Original NASA ASRS Text

Title: A B757-200. ON INITIAL CLB AT 1500 FT, THE ACFT WOULD NOT ACCELERATE BEYOND 160 KTS IN VNAV MODE WITH THROTTLES MOVING TO IDLE. AUTOTHROTTLE DISCONNECT SWITCH ERRATIC.

Narrative: THIS INCIDENT OCCURRED ON CLBOUT FROM ZZZ. PREDEP SOP'S WERE FOLLOWED. THE DEP WAS BRIEFED TWICE SINCE I AM RELATIVELY NEW TO THE B757 AND THE FO HAD NOT BEEN TO ZZZ IN SOME TIME. TKOF ROLL WAS NORMAL. WE WERE VERY LIGHT (184000 LBS). ROTATION WAS NORMAL. GEAR WAS RAISED. PITCH WAS APPROX 21-22 DEGS, SOMEWHAT LESS THAN I EXPECTED BASED ON OUR WT. AT 800 FT VNAV WAS SELECTED AND PITCH WAS REDUCED TO 9-10 DEGS. AGAIN, LESS THAN THE 12-13 DEGS I ANTICIPATED TO MAINTAIN V2 +15 KTS. AT 1500 FT, THE INTERNAL SPD BUG INCREASED TO 160 KTS. AIRSPD WAS INCREASED AND FLAPS 1 DEG WERE SELECTED. THE ACFT WOULD NOT ACCELERATE BEYOND 160 KTS AND WE COULD NOT CLB. WE AGREED THIS WAS NOT NORMAL, ABANDONED REDUCED CLB, AND SELECTED NORMAL CLB. THIS DID NOT HELP. THE THROTTLES CAME BACK TO IDLE. I STARTED A DSCNT TO MAINTAIN AIRSPD WHILE PRESSING THE THROTTLE-DISCONNECT BUTTON AND ATTEMPTING TO MANUALLY PUSH UP THE THROTTLES. INITIALLY, THIS DID NOT WORK EITHER. THE THROTTLES STILL TRIED TO COME BACK. A SECOND ATTEMPT TO PRESS THE THROTTLE-DISCONNECT BUTTON, HOLDING IT FOR A COUPLE OF SECONDS WHILE PUSHING THE THROTTLES UP, WAS SUCCESSFUL. HOWEVER, BY THAT TIME WE HAD LOST 500 FT AND HAD GOTTEN A SINK ALERT. THE PROB CORRECTED THE ACFT ACCELERATED NORMALLY. A MAINT RPT WAS FILED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE FMS WAS PROGRAMMED CORRECTLY AND THE AUTOTHROTTLE SYS AND AUTOPLT WERE OPERATIONAL WITH NO OPEN RPTS. THE RPTR SAID NO RPT FROM MAINT WAS RECEIVED BY THE CREW ON THE FAILURE OF THE AUTOTHROTTLE SYS TO INCREASE THE SPD AFTER FLAP RETRACTION AND THE FAILURE OF THE AUTOTHROTTLE DISCONNECT SWITCH. THE RPTR STATED WHEN MAINT WAS CONTACTED HE WAS TOLD THE INCIDENT WAS CLOSED. THE RPTR SAID THE ACFT WAS RETURNED TO SVC AND IT WAS HINTED THE COMPANY BELIEVED THE INCIDENT WAS CAUSED BY CREW ERROR.

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.

A B757-200. On initial climb at 1500 ft, the aircraft would not accelerate beyond 160 KTS in VNAV mode with throttles moving to idle. Autothrottle disconnect switch erratic.