757 Engine Roll Back on T/O
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757 Engine Roll Back on T/O
a trusted friend, 757 check airman took off in a P&W powered 757 recently purchased from a respected major airline in the USA.
At about 2500'agl, one engine rolled back (reduced thrust) but did not quit.
The plane returned safely for a landing on the remaining engine.
The oil pressure went to -4.
The circuit breaker for the spar valve (fuel valve at the wing) was found open, though it had been checked prior to engine start.
The FAA was aboard and praised the crews actions. The EEC is suspected, but not fully understood at this time what happened.
A boroscope of the engine showed a good engine mechanically speaking.
The EEC was replaced and the plane was safely flown a couple thousand miles to home base.
1. Have any of you guys or gals had this happen, or heard of something like this happening.
2. any ideas? the FAA guys are stumped.
At about 2500'agl, one engine rolled back (reduced thrust) but did not quit.
The plane returned safely for a landing on the remaining engine.
The oil pressure went to -4.
The circuit breaker for the spar valve (fuel valve at the wing) was found open, though it had been checked prior to engine start.
The FAA was aboard and praised the crews actions. The EEC is suspected, but not fully understood at this time what happened.
A boroscope of the engine showed a good engine mechanically speaking.
The EEC was replaced and the plane was safely flown a couple thousand miles to home base.
1. Have any of you guys or gals had this happen, or heard of something like this happening.
2. any ideas? the FAA guys are stumped.
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mid-1980's dual "flame-outs"
"... engine rolled back (reduced thrust) ... EEC is suspect ... heard of something like this [?] ..."
Early B767 (JT9D) had a few interesting parallels -- usually related to the PROXIMITY of the Fuel Shutoff Switch to the EEC's alternate action Switch (first design/location immediately behind the Fuel Shutoff Switch).
During flight test, and then later on the line, the EEC would subtly drift asleep, and some pilots would unthinkingly (routine over-learned response) cycle the EEC's Switches OFF then ON. That EEC switch (one for each engine) was maybe too close to the FUEL SHUTOFF Switch (EEC Switch later re-located to the Overhead Panel).
= = = two cases on the line = = =
B767 Fuel Lever -proximity to EEC switch
[not much info on this first UA example]
NTSB Identification: LAX86MA161 .
... UNITED AIRLINES
... Monday, March 31, 1986 in SAN FRANSISCO, CA
Aircraft: BOEING 767-222, registration: N609UA ...
WHILE CLIMBING THROUGH 3000 FEET AGL, DURING THE INITIAL CLIMB PHASE OF THE FLIGHT, BOTH ENGINES FLAMED OUT.
THE CREW WAS ABLE TO RESTART BOTH ENGINES AND RETURN TO THE AIRPORT OF DEPARTURE FOR AN UNEVENTFUL LANDING.
The National Transportation Safety Board determines the probable cause(s) of this incident as follows:
FUEL SYSTEM, FUEL SHUTOFF..STARVATION
FUEL SUPPLY.. INADVERTENT DEACTIVATION.. PILOT IN COMMAND
Contributing Factors
PHYSICAL IMPAIRMENT (HYPOGLYCEMIA/DIET) ... PILOT IN COMMAND
[not stated explicitly -- UA / 31Mar86 B767-222 N609UA at 1504 pst departing SFO in VMC "both engines flamed-out" / pilot moved both Fuel Control Switches to CUTOFF. ]
= = = = =
DA / 30Jun87 B767 departed LAX, message indicating EEC (Electronic Engine Control) failure on one engine. FM procedure was to retard both Thrust Levers to a mid-position, then both EEC Switches OFF.
Climbing past 2000', as a reaction to the EEC fault annunciation, DA's crew inadvertently moved both Fuel Control Switches to CUTOFF. Dual engine shutdown, descended. Engine start initiated immediately, PA annoucment ordering pax to prepare for ditching; at 500' recovered thrust to both engines.
Crew training procedures required the EEC Switches be operated one at a time. But for both pairs of the EEC and Fuel Control Switches on B767 it was possible to actuate one or both switches simultaneously. Furthermore, both Fuel Control Switches could be moved with one hand.
Fuel Control Switches (lever lock) and EEC Switches (alternate action switches) were paired behind each Throttle Lever on the Center Console; upper/fwd were the Fuel Control Switches; lower/aft were the EECs. Either pair of switches could be "gang" operated with one hand.
FAA's AD ordered mod' installed to inhibit simultaneous activation of the Fuel Control Switches: FAA ordered that a clear acyrlic GUARD be installed between the Fuel Control Switches.
Fuel Control Switches were lever-lock switches, required a lifting action to move switch from RUN to CUTOFF. See prior UA B767 similar mishap of 31Mar86 departing SFO.
A dual engine shutdown of UA B767 / Aug'83 after a high altituded engine surge, seems unrelated to '87 cases. [AWST 127: pg 31-2, Jul 20'87; pg 31 Jul 27'87; pg 44 Sep 28'87.] FAA's AD described the DA incident.
= = == =
During flight test on original B767-200 (VA3 later N602UA) I saw the EEC sleep just prior to T/O on 13R at BFI: PIC cycled Thrust Levers fore and aft, no engine response. The usual fix then was to just cycle the EEC switches to awaken the FBW thottles on those first B767s (yes the B767 had some FBW systems).
Early B767 (JT9D) had a few interesting parallels -- usually related to the PROXIMITY of the Fuel Shutoff Switch to the EEC's alternate action Switch (first design/location immediately behind the Fuel Shutoff Switch).
During flight test, and then later on the line, the EEC would subtly drift asleep, and some pilots would unthinkingly (routine over-learned response) cycle the EEC's Switches OFF then ON. That EEC switch (one for each engine) was maybe too close to the FUEL SHUTOFF Switch (EEC Switch later re-located to the Overhead Panel).
= = = two cases on the line = = =
B767 Fuel Lever -proximity to EEC switch
[not much info on this first UA example]
NTSB Identification: LAX86MA161 .
... UNITED AIRLINES
... Monday, March 31, 1986 in SAN FRANSISCO, CA
Aircraft: BOEING 767-222, registration: N609UA ...
WHILE CLIMBING THROUGH 3000 FEET AGL, DURING THE INITIAL CLIMB PHASE OF THE FLIGHT, BOTH ENGINES FLAMED OUT.
THE CREW WAS ABLE TO RESTART BOTH ENGINES AND RETURN TO THE AIRPORT OF DEPARTURE FOR AN UNEVENTFUL LANDING.
The National Transportation Safety Board determines the probable cause(s) of this incident as follows:
FUEL SYSTEM, FUEL SHUTOFF..STARVATION
FUEL SUPPLY.. INADVERTENT DEACTIVATION.. PILOT IN COMMAND
Contributing Factors
PHYSICAL IMPAIRMENT (HYPOGLYCEMIA/DIET) ... PILOT IN COMMAND
[not stated explicitly -- UA / 31Mar86 B767-222 N609UA at 1504 pst departing SFO in VMC "both engines flamed-out" / pilot moved both Fuel Control Switches to CUTOFF. ]
= = = = =
DA / 30Jun87 B767 departed LAX, message indicating EEC (Electronic Engine Control) failure on one engine. FM procedure was to retard both Thrust Levers to a mid-position, then both EEC Switches OFF.
Climbing past 2000', as a reaction to the EEC fault annunciation, DA's crew inadvertently moved both Fuel Control Switches to CUTOFF. Dual engine shutdown, descended. Engine start initiated immediately, PA annoucment ordering pax to prepare for ditching; at 500' recovered thrust to both engines.
Crew training procedures required the EEC Switches be operated one at a time. But for both pairs of the EEC and Fuel Control Switches on B767 it was possible to actuate one or both switches simultaneously. Furthermore, both Fuel Control Switches could be moved with one hand.
Fuel Control Switches (lever lock) and EEC Switches (alternate action switches) were paired behind each Throttle Lever on the Center Console; upper/fwd were the Fuel Control Switches; lower/aft were the EECs. Either pair of switches could be "gang" operated with one hand.
FAA's AD ordered mod' installed to inhibit simultaneous activation of the Fuel Control Switches: FAA ordered that a clear acyrlic GUARD be installed between the Fuel Control Switches.
Fuel Control Switches were lever-lock switches, required a lifting action to move switch from RUN to CUTOFF. See prior UA B767 similar mishap of 31Mar86 departing SFO.
A dual engine shutdown of UA B767 / Aug'83 after a high altituded engine surge, seems unrelated to '87 cases. [AWST 127: pg 31-2, Jul 20'87; pg 31 Jul 27'87; pg 44 Sep 28'87.] FAA's AD described the DA incident.
= = == =
During flight test on original B767-200 (VA3 later N602UA) I saw the EEC sleep just prior to T/O on 13R at BFI: PIC cycled Thrust Levers fore and aft, no engine response. The usual fix then was to just cycle the EEC switches to awaken the FBW thottles on those first B767s (yes the B767 had some FBW systems).
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a question to clarify first please.
Was this aeroplane, by any chance taxied out on one engine and the second, soon to be "failed" engine started very soon, say just before actual T/O roll?
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The circuit breaker for the spar valve (fuel valve at the wing) was found open, though it had been checked prior to engine start.
Green-dot
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to sevenstrokeroll:
Any new info to the cause of- or source available regarding this incident?
It was mentioned that an EEC was replaced but what was at fault regarding the spar valve issue?
Thanks,
Green-dot
Any new info to the cause of- or source available regarding this incident?
It was mentioned that an EEC was replaced but what was at fault regarding the spar valve issue?
Thanks,
Green-dot
Last edited by Green-dot; 15th Aug 2008 at 06:59. Reason: To be more specific.
