UNITED 787, N27958, again

[gearlever]

How on earth can this happen within days?

Incident: United B789 at Rome on Jul 7th 2020, high speed return landing (http://avherald.com/h?article=4d9aa79c&opt=0)

[tdracer]

Ask the maintenance team. It's pretty obvious there is a problem with the leading edge devices that's not getting fixed.

[Out Of Trim]

Seems like this aircraft should be withdrawn from use until, the leading edge slats are properly repaired!

[DaveReidUK]

There seems to be some confusion in those Avherald articles, which mention the "left hand leading edge flaps".

Is this a reference to the Krueger flap (of which there is only one on each wing) or the inboard/outboard L/E slats ?

[42...]

So maintenance test flights not possible anymore?

[Capi_Cafre']

Just curious; is that an east coast or a west coast build?

[tdracer]

Planespotters says Everett:
https://www.planespotters.net/airframe/boeing-787-9-dreamliner-n27958-united-airlines/r1mkko
(Since I retired I can no longer access the Boeing data base to confirm)

[DaveReidUK]

Yes, built at KPAE.

Incidentally, the folks at Aviation Safety Network, who can normally be relied on, confirm that the issue was with the slats on the left wing. Disregard any references to flaps.

[gearlever]

Does it make any difference?
Just asking...

[DaveReidUK]

Right now, I would imagine that United are looking at a whole range of possible causal factors (the aircraft still isn't back in revenue service). I would expect that to include possible manufacturing/QC issues.

So yes, it might.

[LME (GOD)]

For all those armchair mechanics posting drivel....Intermittent wiring problems are difficult to find on standard systems, throw in a prox sensor it just makes it harder to isolate.
No airline want repeated air-interrupts, but setting up ad-hoc maintenance test flights in Europe is very difficult to accomplish when you dont have crews available that are flight test qualified.

[gearlever]

As a Commercial Pilot for more than 30 yrs, I never ever heard about such incompetence.

[lomapaseo]

Rather strong words without any supporting facts

[jolihokistix]

Hmmm... I saw the three Narita incidents with this same aircraft reported in the Japanese press last week, and considered posting them here, but it would have meant time performing translation, and life is short, so I took the line of least resistance. Hope the find the Gremlin.

[Dave Therhino]

From the reports I've seen from the Narita turnbacks, they are getting the FLAP DRIVE message and an associated specific maintenance message due to problems with one of the rotary slat drive sensors (or sensor circuits). The slats themselves and their actuating system were not failed, but they get disabled when a valid rotary drive sensor signal is lost. The FCOM has procedures for such an event. I have not heard anything about why they are struggling to troubleshoot the identified problem sensor and circuit.

[tdracer]

For all those armchair mechanics posting drivel....Intermittent wiring problems are difficult to find on standard systems, throw in a prox sensor it just makes it harder to isolate.
No airline want repeated air-interrupts, but setting up ad-hoc maintenance test flights in Europe is very difficult to accomplish when you dont have crews available that are flight test qualified.

Yes, intermittent wiring issues can be a nightmare to troubleshoot. I got a few ataboys over the years when (due to my detailed system knowledge combined with the description of the symptoms) I was able to figure out where to tell them to look for the problem (usually a chaffed wire bundle).
That being said, when you've had more than one air turnback for the same problem, I'd think they'd want to really confident they'd corrected the issue before they released the aircraft back into line service.

[jimjim1]

time performing translation,

Google translate seems very good now depending on the language. I have been doing some German recently and the result usually reads very well.

I believe Japanese is quite good too. It was the first to use their AI based translation engine. You could just paste the raw links.