[Peetwo]

Hoodlum we may have a problem?

Irony of ironies, some 20 days ago we had the ATSBeaker (as it was then) release the bollocks 2nd interim report into investigation AO-2014-032 - see post: World's best practice in CYA Aviation Accident Investigation. This interim report was released because apparently after 847 days of ATSBeaker investigation a safety issue was identified... :

Inadvertent activation of the elevator control system - pitch uncoupling mechanism

Inadvertent application of opposing pitch control inputs by flight crew can activate the pitch uncoupling mechanism which, in certain high-energy situations, can result in catastrophic damage to the aircraft structure before crews are able to react.
ATSB Safety Issue No: AO-2014-032-SI-01

   
This interim report was apparently brought to the attention of the Indonesian AAI the NTSC who saw similarities to a reported incident involving an ATR-72 on the 27 June 2016, which they are now investigating:

Accredited representative to the Indonesian National Transportation Safety Committee investigation of the damage sustained by ATR 72 aircraft, registered PK-WG
 
Investigation number: AE-2016-069
Investigation status: Active
 

• Summary
  

On Monday 27 June 2016, the Indonesian National Transportation Safety Committee (NTSC) commenced an investigation into damage sustained by ATR 72 aircraft, registered PK-WGL. Initial examination of this damage suggested similarities with that found on an Australian-registered ATR 72, registered VH-FVR, which is being investigated by the ATSB (see ATSB investigation AO-2014-032 at ATSB website). On 29 June 2016, the NTSC requested the appointment of an ATSB accredited representative to the NTSC investigation in accordance with clause 5.23 of Annex 13 to the Convention on International Civil Aviation Aircraft Accident and Incident Investigation. This was a result of the ATSB’s experience with the ATR during investigation AO-2014-032 and an accredited representative was appointed to the NTSC investigation that day. To facilitate this support, the ATSB initiated an investigation under the Australian Transport Safety Investigation Act 2003.

The NTSC is responsible for, and will administer the release of the final investigation report into the occurrence involving PK-WGL. Any enquiries regarding the NTSC investigation should, in the first instance, be directed to the:
Ministry of Transportation Fl. 3
Jalan Medan Merdeka Timur No.5
Jakarta  10110
INDONESIA 
Telephone:    +62 21 351 7606
Facsimile:  +62 21 351 7606
Email: knkt@dephub.go.id
Email: [email=knkt@dephub.go.id]knkt@dephub.go.id
[/email]Website: http://kemhubri.dephub.go.id/knkt
 
General details

Date: 27 Jun 2016
 
Investigation status: Active
 
Investigation type: External Investigation
 
Location   (show map): International
 
State: International
 
Occurrence class: Technical
 
Occurrence category: Technical Analysis
 
Report status: Pending 
 
 


Last update 01 July 2016

 
- I just love the irony of that NTSC request for an ATSB accredited rep, as per ICAO Annex 13 para 5.23:

Rights

5.23 Any State which on request provides information, facilities or experts to the State conducting the investigation shall be entitled to appoint an accredited representative to participate in the investigation.

Note.— Any State that provides an operational base for field investigations or is involved in search and rescue or wreckage recovery operations may also be entitled to appoint an accredited representative to participate in the investigation.

Shit I hope the Indo's listen to what the astute Alan Stray taught them and they don't follow the Beaker template for incident investigations. Otherwise there will be ATR's dropping from the sky over Indo waters!

Tick tock

Update: Also now on the Planetalking blog, see my comment HERE:  

"...Damaged Virgin Australia turbo-prop risked crashing for five days
ATSB alerts the world to a safety issue that could have crashed a Virgin Australia turbo-prop..."

Ben Sandilands


Damage to the T-tail of the Virgin Australia ATR

Update - via SMH today:

Plane lucky: an aviation escape
Date July 11, 2016 - 12:00AM

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Martin Aubury

An ATR 72-600 aircraft operated by Virgin Australia prepares to land at Sydney Airport. Photo: Brendon Thorne

In February 2014 the crew of a small airliner flying from Canberra to Sydney mishandled their flight controls; one pilot pushed, the other pulled. The ATR 72 operated by Virgin entered such a violent manoeuvre that a flight attendant was seriously injured and the aircraft encountered loads far beyond what it was designed to sustain. Somehow it held together. Structural damage was so severe that the ATR 72 was visibly twisted, but nobody noticed and for the next five days the weakened airliner stayed in service.

Several months later, in December 2014, the pilots of an AirAsia Airbus A320 flying from Indonesia to Singapore made a similar mistake. They mishandled their joint response to a sudden deviation from steady flight; one pushed, the other pulled. The airliner did not recover. All 162 on board died. In due course Indonesian authorities published a timely and thorough accident report. AirAsia was vilified and Indonesian aviation in general denigrated.

It took a year longer for the Australian Transport Safety Bureau to tell us of the near-disaster here. ATSB's interim report, published last month, went largely unnoticed; perhaps we were too distracted by the election campaign. The report is sketchy and understates the seriousness of what went wrong. The report tells us what happened in the air but says little about why the damage was not found on the ground.

The captain and co-pilot of the ATR 72 each have a control column connected by cables and links to two moveable surfaces called elevators, hinged along the rear edge of the horizontal tail. Normally a pull on either control moves both elevators up; this exerts a down load on the tail and the aircraft pivots nose up.


Modern designs like the ATR 72 have an extra safety feature. The left and right systems are copies of each other, such that left control column connects directly to the left elevator and right control connects to right elevator. In normal operation, the left and right systems are connected together and move in unison. However, if either of the systems jams, a clutch between them opens and either the captain or co-pilot can safely fly the aircraft with the functioning system.

During descent to Sydney the ATR 72 increased speed unexpectedly. The co-pilot, who was flying the aircraft tried to slow it, by reducing power and by pulling back on his control column to raise the aircraft's nose. The captain was unsure if the co-pilot's response would be sufficient, so gently pulled on his own control to assist. With both pilots making simultaneous nose up inputs, the aircraft rapidly pitched up. The co-pilot responded immediately by reversing his control input, to nose down. Opposite control inputs from captain and co-pilot had the unintended consequence of left and right elevator control systems uncoupling from each other. This then caused left and right elevators to move in opposite directions; a configuration for which the aircraft was never designed.

As ATSB puts it ".....asymmetric elevator deflections resulted in a large asymmetric aerodynamic load being generated on the horizontal stabiliser. That load exceeded the design strength requirements for the stabiliser structure, resulting in significant damage. Such a large exceedance has the potential to result in catastrophic damage to the stabiliser and a subsequent loss of control."

Later analysis showed that much of the aircraft structure was overloaded, some by 47 per cent. Damage was extensive and when eventually found took months to repair. The whole of the tail structure, vertical and horizontal, had to be replaced.

ATSB coyly concedes pilots make mistakes. "Despite pre-existing, well-established and trained procedural risk controls to prevent dual control inputs in normal operation, the risk controls were readily, but inadvertently, bypassed by the crew on this occasion."
Much the same mistake contributed to the AirAsia crash. The A320 is a bigger airliner than the ATR 72 and its controls are more complicated, as was the accident scenario. Plus, we know from cockpit recordings that miscommunication compounded the confusion.

The Indonesian captain and French co-pilot spoke in English but it was not their native tongue. The captain needed the co-pilot to assist by pushing his control forward to make the aircraft pitch down. The captain should have instructed "Push Down" but repeatedly said "Pull Down, Pull Down". The co-pilot continued to pull, opposing the captain. The A320 crashed and reinforced the stereotype of unsafe aviation in Indonesia.

By contrast the Australian crew quickly regained control and avoided showering wreckage over outer Sydney. Point is, neither the crew nor Virgin's maintenance organisation realised that the ATR 72 was seriously weakened. It seems appalling that the damage was not found for five days and that ATSB's interim report does not explain how this came about. Suffice to say, all who flew in the damaged ATR 72 were in grave peril.
Sometimes luck alone keeps Australia's aviation reputation safe.

Martin Aubury is a retired aeronautical engineer who has been involved with aircraft design and regulation for more than 50 years.


Read more: http://www.smh.com.au/comment/plane-lucky-an-aviation-escape-20160708-gq1i4k.html#ixzz4E4Q4rObV

MTF...P2