A red herring? Perhaps. But the report doesn't diminish or dismiss pilot
error. In fact, it's pretty clear that the investigators think the pilots
screwed up royally. (In fact, they note that the very language that they
used to communicate was confusing, specifically when the pilot told the
co-pilot to "pull down" on the gear controls, which actually sent the plane
into an ascent and caused the stall.)

But it's also clear that the RTL repeatedly failed and had to be re-set,
which put the co-pilot in control of the plane while the pilot attempted to
fix the failure. Per the report, electrical interruptions to the RTL
happened three times in 13 minutes and ultimately disengaged the
auto-pilot. And the RTL failure was due, the report says, to that cracked
solder joint.



Best,



Mike



*From:* Bhanu Sood [mailto:[log in to unmask]]
*Sent:* Tuesday, December 01, 2015 10:23 PM
*To:* TechNet E-Mail Forum; Mike Buetow
*Subject:* Re: [TN] Airbus crash pinned (in part) on solder joint failures



From page 18 of 206:

"
At 2316:44 UTC, the sixth Master Caution triggered by AUTO FLT FAC 1 + 2
FAULT and followed by FDR signature of alteration of parameters of
components controlled by FAC 2 such as RTLU 2, Windshear Detection 2 and
Rudder Travel Limiter Actuator 2. The Auto Pilot (A/P) and the Auto-thrust
(A/THR) disengaged. Flight control law reverted from Normal Law to
Alternate Law. The aircraft started to roll to the left up to 54° angle of
bank. Nine seconds after the autopilot disengaged, the right side-stick
activated. The aircraft roll angle reduced to 9° left and then rolled back
to 53° left. The input on the right side-stick was mostly pitch* up and the
aircraft climbed up to approximately 38,000 feet with a climb rate of up to
11,000 feet per minute*.
"

From page 52 of 106

"
At 2317:41 U*TC the aircraft reached the highest altitude of 38,500 feet
(ISIS) and largest roll angle at 104° to the left. *The aircraft then
descended with a rate up to 20,000 feet per minute momentarily afterward
the rate of descent was recorded at average of 12,000 feet per minute until
the end of recording.
"



An ascent rate of 11000ft/min is highly unlikely on a commercial aircraft,
the CFM56-5B fans on this A320 most certainly were not designed to provide
such thrusts, at close to max takeoff weight. The most likely cause is an
extreme vertical wind shear (exceeding 10kt per 100ft) which caused a
vertical stall.

The solder-joints are a red herring IMHO..



Bhanu



On Tue, Dec 1, 2015 at 9:27 AM, Mike Buetow <[log in to unmask]>
wrote:

Here's the report: http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm



Discussion of the electrical short and cracked solder joint begins on page
104.





Best,



Mike



Mike Buetow

PCD&F/Circuits Assembly

w/m: 617-327-4702

@mikebuetow



The 2015 CIRCUITS ASSEMBLY *Directory of EMS Companies:*
circuitsassembly.com/dems


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Bhanu Sood
Tel: (202) 468-8449

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