Unusual Troubleshooting
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Unusual Troubleshooting
"N379AA, a Boeing 767-300 aircraft operated by American Airlines, was conducting flight AAL65 from Zürich-Kloten, Switzerland (LSZH) to New York/John F Kennedy Intl, NY (KJFK). During cruise flight, the crew received a leading edge slat asymmetry EICAS message. The crew coordinated with Shannon ATS and departed flight planned route to troubleshoot the indication with consultation from the operator. After determining that the flap lever was out of its detent, the flight crew corrected the situation and continued en route. However, due to the additional fuel burned during the period of troubleshooting, the crew coordinated with Moncton Centre to divert the flight to Bangor Intl, ME (KBGR) for a fuel stop. The flight landed at KBGR without further incident."
One has to wonder what they did to burn up so much gas. Descend to FL200 for an extension and retraction?
One has to wonder what they did to burn up so much gas. Descend to FL200 for an extension and retraction?
One has to wonder what they did to burn up so much gas. Descend to FL200 for an extension and retraction?
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One wonders why the EICAS took so long to flag up?? If indeed it was a left over from takeoff.
Jammed Stab: where did you get such detailed information about the cockpit crew actions & reasons?
Jammed Stab: where did you get such detailed information about the cockpit crew actions & reasons?
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And in the old days they would give the crew lobsters as a reward for choosing their airport as a fuel stop. 
There weren't enough for the pax so you had to be discreet when sneaking them up the stairs into the cabin. It might have the look of impropriety, kinda like the C-5's that used to make lobster runs to Navy Brunswick in Maine until someone complained.
From an old Boeing B-763 manual:
The first item is:
However, if they indeed had LE SLAT ASYM instead, there is a warning not to use FMC fuel predictions and after turning on the igniters (this checklist presumes you are about to land) the next step is
Maybe at that point they noticed that the flap lever was slightly out of the up detent. They wiggled the handle and all the bad indications disappeared would be my guess.
Sounds like they took some turns in holding with Shannon before going oceanic to make sure that they had done the proper groupthink exercise with the dispatcher, subject matter expert, maintenance, crew scheduler and van driver.
By the time everyone had weighed in with an opinion maybe the '76 had burned enough fuel to require an extra stop after the crossing.
I doubt that they descended to FL200, however there is a warning about not exceeding placard flap speeds and max altitude for flaps and slats extended is FL200.
Also, you would think that if there really were a leading edge asymmetry, you would see it on the yoke in level flight and it would be visible through the cabin windows.
There weren't enough for the pax so you had to be discreet when sneaking them up the stairs into the cabin. It might have the look of impropriety, kinda like the C-5's that used to make lobster runs to Navy Brunswick in Maine until someone complained.
LE SLAT DISAGREE
FLAP LEVER - CHECK
Ensure flap lever in desired flap setting detent. If placing flap lever in appropriate detent extinguishes LEADING EDGE light and LE SLAT DISAGREE message, continue normal operation.
Ensure flap lever in desired flap setting detent. If placing flap lever in appropriate detent extinguishes LEADING EDGE light and LE SLAT DISAGREE message, continue normal operation.
FLAP LEVER - SET
Sounds like they took some turns in holding with Shannon before going oceanic to make sure that they had done the proper groupthink exercise with the dispatcher, subject matter expert, maintenance, crew scheduler and van driver.
By the time everyone had weighed in with an opinion maybe the '76 had burned enough fuel to require an extra stop after the crossing.
I doubt that they descended to FL200, however there is a warning about not exceeding placard flap speeds and max altitude for flaps and slats extended is FL200.
Also, you would think that if there really were a leading edge asymmetry, you would see it on the yoke in level flight and it would be visible through the cabin windows.
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Maybe they were using the ice light as well to take a look although it may not illuminate things well.
This Aviation Herald report explains more clearly what happened to necessitate the diversion.
Incident: American B763 over Atlantic on Aug 6th 2016, slat asymmetry in cruise flight
Incident: American B763 over Atlantic on Aug 6th 2016, slat asymmetry in cruise flight
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One of the commenters to that post is, like me, puzzled that they were reported to have had a leading edge asymmetry rather than a disagree indication. Seems like hydraulic power to the slats would be turned off if there were an asymmetry indication, right? I'm not sure jiggling the handle would fix the problem in this case, wouldn't the slats be locked out for the remainder of the flight?
And inevitably, there is some discussion in the AV Herald comments of Hoot Gibson's wild ride on TWA 841 and whether it was crew-induced.
As I surmised earlier, AA 65 did take a turn or two with Shannon to sort things out before doing the crossing:
American Airlines (AA) #65 ? 06-Aug-2016 ? ZRH / LSZH - KJFK ? FlightAware
And inevitably, there is some discussion in the AV Herald comments of Hoot Gibson's wild ride on TWA 841 and whether it was crew-induced.
As I surmised earlier, AA 65 did take a turn or two with Shannon to sort things out before doing the crossing:
American Airlines (AA) #65 ? 06-Aug-2016 ? ZRH / LSZH - KJFK ? FlightAware
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Haven't found the discussion re TWA 841 so my comment here may simply be repetition. I was flying for a B727 operator at the time and the word on the street was that the crew initiated a well known practice for improving performance at altitude by disabling the LE devices, (by pulling the LE Devices CB), and extending the TE flap to the '1' position, as this involved the TE flap only moving horizontally out, thus increasing the wing area. It was my understanding that this was a well known unofficial practice among the B727 fraternity. In the case of TWA 841 it is believed the wrong CB was pulled, the TE flaps stayed in and the LE devices deployed, jet upset followed.
If this post is all wrong or irrelevant I will delete.
If this post is all wrong or irrelevant I will delete.
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The TWA 841 flight crew swore and be damned that they had never heard of the technique of pulling the slat breaker and extending two degrees of flaps.
And the captain said he had no memory of erasing the CVR after the flight.
Had a 'leading edge asymmetry' indication on the 767-400 shortly after selecting flaps zero.
Sent the relief Pilot back to take a look, he confirmed all slats and flaps retracted normally, we continued to destination.
But you're out of the slat business once that warning comes on, any asymmetry is detected and they're locked out for good reason.
We made a no slat landing with a VREF around 180 knots, turned out to be a bad sensor.
Sent the relief Pilot back to take a look, he confirmed all slats and flaps retracted normally, we continued to destination.
But you're out of the slat business once that warning comes on, any asymmetry is detected and they're locked out for good reason.
We made a no slat landing with a VREF around 180 knots, turned out to be a bad sensor.
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About 767 slats- History
On one of the first test flights of the 767- the right wing LE slats did NOT retract fully- and got sort of bent in an intermediate position. Sort of an over-center issue.
Result was a very fast landing. The slats removed and spirited away to an little known lab area in the everett faciity for a post mortem.
The reason was a fubar design of the slat mechanism- which a few designers using early cad systems had tried to explain had wrong mechanical pivot points- linkage - but failed.
In those days - cad-cam- catia was in very early stages- and old line managers had little trust in its output or ability to model linkages
As a result by the time of first flight- about 4 to 6 ( from memory ) sets of slat mechanisms had to be reworked/replaced after assembly but before they were mounted.
Result was a very fast landing. The slats removed and spirited away to an little known lab area in the everett faciity for a post mortem.
The reason was a fubar design of the slat mechanism- which a few designers using early cad systems had tried to explain had wrong mechanical pivot points- linkage - but failed.
In those days - cad-cam- catia was in very early stages- and old line managers had little trust in its output or ability to model linkages
As a result by the time of first flight- about 4 to 6 ( from memory ) sets of slat mechanisms had to be reworked/replaced after assembly but before they were mounted.
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in early 90's on B757/767 we used to get this ECIAS at random intervals. A selection of LED anti-ice solved it. It was thought to be condensation on the sensors. Perhaps this was why the message took so long to appear; they were in the CRZ. OK, it says the lever was out of slot; perhaps it always had been and somehow jiggled a little further to trigger the EICAS, but I would have expected the EICAS to be triggered if it was not seated correctly from the getgo.
Do only B737 drivers bang the flap lever in the gate after selecting UP to ensure it really is seated?
Do only B737 drivers bang the flap lever in the gate after selecting UP to ensure it really is seated?
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on inadequate acceleration in a dc-9 out of 10k back in the dark ages, after a modicum of brainstorming, i had the fo ask atc for a return vector to the airport, when what to my wondering eye should appear but the slat extend light, which the capt had to lean considerably forward to see.
the fo said i never called for them to be retracted. which i though ungracious not to mention immaterial.
the fo said i never called for them to be retracted. which i though ungracious not to mention immaterial.
