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-   -   Maintenance Lapse Identified as Initial Problem Leading to Lion Air Crash (https://www.pprune.org/tech-log/616624-maintenance-lapse-identified-initial-problem-leading-lion-air-crash.html)

BedakSrewet 3rd Jan 2019 06:59

Unless I missed it, I have been wondering why the Lion Air Engineers did not consult the ( Jakarta based ) BOEING Tech Rep(s) when they were trouble shooting the problem following the flight from DPS to CGK ?

ATC Watcher 3rd Jan 2019 08:14

And we probably will never know for sure what happened as CNN this morning reported that the search for the CVR and more debris have been abandoned

IFixPlanes 3rd Jan 2019 15:59


Originally Posted by CONSO (Post 10349896)
RE FCeng84 # 63
Interesting - a pic of " typical " AOA Sensor shows 8 holes in post # 58
...

That is not a "typical" AOA Sensor. This pic shows the sensor of an B737MAX Sensor!

DaveReidUK 3rd Jan 2019 16:37


Originally Posted by IFixPlanes (Post 10350689)
That is not a "typical" AOA Sensor. This pic shows the sensor of an B737MAX Sensor!

Are you implying that it's different from the sensor on the NG ?

IFixPlanes 3rd Jan 2019 16:43

No, PN 0861FL1 can be installed on NG and MAX.

DaveReidUK 3rd Jan 2019 17:49


Originally Posted by IFixPlanes (Post 10350732)
No, PN 0861FL1 can be installed on NG and MAX.

Thanks, that helps to discount the theory that the wrong part number was fitted to the accident aircraft and had to be forced to fit.

phil gollin 3rd Jan 2019 18:25


Originally Posted by ATC Watcher (Post 10350274)
And we probably will never know for sure what happened as CNN this morning reported that the search for the CVR and more debris have been abandoned



IF that is confirmed as a final decision, then I find it unbelievable.

tarkay01 3rd Jan 2019 18:41


Originally Posted by phil gollin (Post 10350837)

IF that is confirmed as a final decision, then I find it unbelievable.

No, Lion is stopping their search. The Indonesian government is going to step in and resume searching, albeit with arguably less capable equipment.


wiedehopf 3rd Jan 2019 18:53


Originally Posted by phil gollin (Post 10350837)

IF that is confirmed as a final decision, then I find it unbelievable.

Any money more spent on this search would probably be much better spent in extra sim time for the pilots.
Don't think the CVR will tell you why the AoA sensor was reading wrong.

An improvement for MCAS is already under way at Boeing as far as i understood. Anyway any improvement in that area can be made without finding any further parts.

What do you think further search will provide?

DaveReidUK 3rd Jan 2019 19:10


Originally Posted by wiedehopf (Post 10350872)
Don't think the CVR will tell you why the AoA sensor was reading wrong.

No, of course it won't.

But the CVR will, in all likelihood, help the investigators (and us) to understand what happened differently on the accident flight compared to the previous flights where the same problems were mitigated by the crews' actions.

Personally, I think we stand to learn a lot from that.

underfire 4th Jan 2019 00:21


No, PN 0861FL1 can be installed on NG and MAX.
This is correct. UT manufactures only 2 models of the sensor, one wing mounted, Model 0012, and the fuselage mounted Model 0861...

CONSO 4th Jan 2019 00:43


Originally Posted by underfire (Post 10351174)
This is correct. UT manufactures only 2 models of the sensor, one wing mounted, Model 0012, and the fuselage mounted Model 0861...

Since the sensor shown seems to be for the left side,is there a different dash number for the right side or is the change taken care of by mounting ' upside down ' on right side and acomodated via electrical ?

DaveReidUK 4th Jan 2019 09:53


Originally Posted by CONSO (Post 10351185)
Since the sensor shown seems to be for the left side,is there a different dash number for the right side or is the change taken care of by mounting ' upside down ' on right side and acomodated via electrical ?

Given that, as posted earlier, the physical movement limits of the AoA vane are the same in both directions, there is no need for the sensor to be handed. The aircraft is clever enough to understand that clockwise rotation of one vane means the same as anticlockwise rotation of the one on the other side.

The other giveaway is that the Part Description on vendors' and MRO websites doesn't include a "LH" or "RH" qualifier:

https://cimg8.ibsrv.net/gimg/pprune....d9066ff84f.jpg

MickG0105 4th Jan 2019 10:43


Originally Posted by tarkay01 (Post 10350858)
The Indonesian government is going to step in and resume searching, albeit with arguably less capable equipment.

Less capable equipment? That'd be difficult. The MPV Everest was only fitted with a pair of Triton XLX ROVs and a Forum Comanche ROV. None of those ROVs are particularly useful for search work unless you intend to search visually for a target sitting on the surface of the sea floor. On the basis that the CVR is almost certainly buried in mud the whole Everest exercise was essentially a waste of time and money. What's required is an acoustic sub-bottom profiler.

underfire 4th Jan 2019 13:02

given the 'keyed' bolt pattern, the unit can be either RH or LH
https://cimg2.ibsrv.net/gimg/pprune....0c899aeade.png

DaveReidUK 4th Jan 2019 15:38


Originally Posted by underfire (Post 10351620)
given the 'keyed' bolt pattern, the unit can be either RH or LH

Correct, though the photo isn't the variant that's fitted to the 737NG/Max.

See my previous post, and this is what it looks like in situ, courtesy of Burkhard Domke:

https://cimg1.ibsrv.net/gimg/pprune....1d1b9c0a72.jpg

There are no fewer than four locating pegs, plus what look like non-uniformly-spaced mounting bolts, designed to Murphy-proof the sensor against being fitted out-of-alignment, but which allow it to serve as the LH or RH sensor.

CONSO 4th Jan 2019 15:45


Originally Posted by DaveReidUK (Post 10351442)
Given that, as posted earlier, the physical movement limits of the AoA vane are the same in both directions, there is no need for the sensor to be handed. The aircraft is clever enough to understand that clockwise rotation of one vane means the same as anticlockwise rotation of the one on the other side.

The other giveaway is that the Part Description on vendors' and MRO websites doesn't include a "LH" or "RH" qualifier:

https://cimg8.ibsrv.net/gimg/pprune....d9066ff84f.jpg


translation- must be an electrical function built in somewhere in software or wiring ? or having a connector pin open/blocked differently on each side. ....

underfire 4th Jan 2019 16:31


Correct, though the photo isn't the variant that's fitted to the 737NG/Max.
The AOA sensor you showed is from Rosemont. The AOA sensor on the MAX is supplied by United Technologies.

This looks like its installed on a battleship, not a max!

EDIT: Even though the UT AoA sensor is advertised as mounted on the LionAir MAX, either there are multiple options, or multiple manufacturers...

Spirit of Renton MAX is the rosewood you mentioned Dave

https://cimg4.ibsrv.net/gimg/pprune....4c0bca8741.jpg

DaveReidUK 4th Jan 2019 16:45


Originally Posted by underfire (Post 10351800)
The AOA sensor you showed is from Rosemont. The AOA sensor on the MAX is supplied by United Technologies.

Rosemount Aerospace Inc is a division of what was United Technologies, now Collins Aerospace.

Air Data Systems - Collins Aerospace

IFixPlanes 4th Jan 2019 16:46

Here is the "keyed" bolt pattern of the 737MAX AOA:
https://s15.directupload.net/images/...p/owqlap6h.jpg
You can see that is is symmetrical and due to the fact that the alignment bushings are at 0 and 180 it can be installed on both side simply by a 180 turn.
@ underfire:
The MAX also use the PN 0861FL1 (Rosemont) - check the IPC (if you can...)


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