[Peetwo]

Point of order Mr. Chairman.

"The elevators normally move in the same direction and in equal amounts but there is a mechanism, the pitch uncoupling mechanism, which allows them to operate independently in the event one jams."

"By pushing the control columns in opposite directions, the Virgin pilots activated this mechanism and subjected the aircraft to stresses it was not designed to take."

This whole ATSB, CASA and ATR dialogue omits one essential element. The aircraft did not have a ‘control jam’. There was no cool headed decision made to ‘disengage’ the elevator channels and no requirement to do so. There was also no ‘auto pilot’ fault flagged. So, how did the ‘disconnect’ event which led to the aircraft being damaged occur? Was the AP actually fully disengaged before 'strong' manual input? Why did one crew member think pull ‘up’  was the cure and the other believe ‘push’ down a solution? Seems to me there are there serious questions which need to be answered before batting the ball back to ATR. There may well be other incidents where the crew became confused and inadvertently disconnected the elevator channels – but I’m blessed if I can find them. There are a couple of incidents where this has been deliberately done – without damage to the airframe. Perhaps there is a much simpler, untested, line if inquiry close to home. Seems to me the obvious  questions should be eliminated first, before this esoteric discussion on the black art of test flying and certification is entered into – at great expense

If it walks like a duck - just saying..

Toot toot.

Update: PT & Discus.

Excellent deliberations "K" to which I totally agree...

As "K" points out the whole idea of having a pitch disconnect system is to have a back-up in the unlikely event of a pitch control jam. Such a situation calls for a conscious decision and deliberate actions by the flight crew - something that obviously did not occur in this incident. Therefore, how can the ATSB seriously be calling for what basically amounts to a re-certification process, for a tried and true airframe (in service since 1989 for the -72 and 1984 for the -42); when seemingly the other (now extremely mouldy) Swiss cheese holes have not been thoroughly investigated and/or explained? 

Spot the disconnections?  

Quoting ATSB high viz spokesperson Greg Hood:

"The ATSB released its first interim report into this incident in July last year. That report identified a significant safety issue relating to the strength of the aircraft's tail structure in the event of a pitch disconnect," Mr Hood says.

"Our concern is that, given the design of the ATR42 and ATR72 aircraft, opposing control inputs can result in aerodynamic loads that may exceed the design strength of the tail structure, causing significant damage."

"Since we identified this issue, our aeronautical and structural engineers have conducted extensive analysis based on additional data provided by ATR. The findings of that analysis, supported by an independent peer review from the UK Air Accidents Investigation Branch, confirmed our initial concerns."

"The ATSB welcomes the engagement with the European and Australian regulators EASA and CASA, and the safety action taken by the manufacturer ATR, who continues to conduct further engineering analysis of the issues identified by the ATSB."

And from the PT article...

ATSB sounds alarm about certification blind spot in ATR turbo-prop
Ben Sandilands 5, 2017 16 Comments
More safety issues with the infamous Virgin Australia ATR 72 incidents of 2014 have emerged

..on the ATSB 2nd interim report and to further highlight this (again) bizarre BASR ATSB disconnect, I refer to an excellent rational & Reasoned Discus comment (note parts in red bold)..  :

Discus
May 6, 2017 at 1:59 pm

It appears that the manufacturer had not identified the risks of uncoupling with both control columns free to move asymmetrically, or that the force required to uncouple would mean that there would be sudden, unavoidable movement in whichever direction a crew member was pushing , pulling or both at the same time, as it was in this case. That is serious if found to completely factual as it derails everything thereafter.

This being the case, it is likely that the requirements of the inspection in accordance with the aircraft maintenance manual did not involve mandatory removal of the fairings that would cover the vast majority of, if not all of that obvious damage.

Without pre-empting the investigation’s findings, it seems that there were some problems in the cockpit . Having one pushing, one pulling to avoid an over speed sounds like very poor flying to me. The subsequent write up for engineering is crucial as to what inspections and checks are mandated.

Given the manufacturer had not identified the possible problem, the engineers may have done everything in accordance with the manuals for what was reported. As an engineer myself and worked in line maintenance for about 30 years, we need to rely on what is reported as being accurate. We are not allowed to deviate from what the manuals tell us. If moderate turbulence is reported and that situation only requires a “General Visual Inspection (GVI)” that is exactly what is done. You lose jobs and or contracts for grounding aircraft and doing inspections etc that are not required by the manufacturer’s manuals for any given report from the flight crew.

In Ben’s previous post https://blogs.crikey.com.au/planetalking/2014/06/10/virgin-australia-flew-13-passenger-flights-in-broken-turbo-prop/ on this incident, it was noted in the comments that the flight crew may not have initially report the turbulence, just the disconnect and it was upon the suggestion of the engineer to write the turbulence up and iirc it was described as “moderate”. In this case it seems a “general Visual Inspection” was required. A GVI really is a walk around.

Boeing for example describes a GVI as done from the ground without special stands or equipment.

Now, if there was obvious damage that was missed the signing engineer , he or she may have serious problems, but if that damage is covered by fairings that are not required to be removed during the required inspection and that inspection was carried out diligently, in accordance with the documentation, that engineer is within their rights to sign off on it.

As usual, there is a sequence of events , lining up the holes in the Swiss cheese, that allowed this to happen starting with the manufacturer , then the crew’s actions whilst flying, possibly their report to engineering and perhaps the engineers.

Careful Discus we all know how sensitive Hoody is when it comes to critiquing and questioning the ATSB BASR approach to AAI - remember this from Hoody's correcting the bollocks page? (reference: Hoodlum gets defensive)

Inaccuracies in reporting of an ATSB investigation In-flight pitch disconnect involving an ATR 72 aircraft

14 July 2016

The article by Martin Aubury, ‘Luck stops an air disaster waiting to happen’, published in several Fairfax publications on 11 July 2016 contains factual errors and misunderstandings. In the interests of ensuring truth and transparency, the ATSB considers it necessary to correct the record. In the article, Mr Aubury cites the ATSB’s on-going investigation into an in-flight pitch disconnect involving a Virgin Australia Regional Airlines (VARA) ATR 72 aircraft while descending into Sydney, NSW on 20 February 2014.

Mr Aubury claims that it took the ATSB several years to publicly report its investigation into the incident. In fact, the ATSB published an initial web update on its investigation on 10 June 2014. A second, interim report was published on the ATSB’s web site on 15 June 2016.

Mr Aubury’s article also claims the ATSB’s interim report ‘understates the seriousness of what went wrong’ and says little about why the damage to the aircraft was not found on the ground for five days.

The ATSB’s investigation into this incident is still ongoing. As discussed in the interim report, the ATSB’s investigation activities to date have included the collection and analysis of maintenance documentation and procedures of the operator and the maintenance organisation. ATSB is also examining the Civil Aviation Safety Authority’s surveillance and approvals involving the operator and maintenance organisation. ATSB is further involved in on-going enquiries and discussions with the aircraft manufacturer in France (ATR), the safety investigation agency in France (BEA), and the European regulatory authority (EASA). ATSB is further involved in on-going dialogue with neighbouring States who have operators utilising the ATR42 and ATR72 aircraft.

The ATSB’s interim report was intended to provide factual information and analysis associated with the identified safety issue. That safety issue highlighted the risk of inadvertent and opposing activation by flight crew of the aircraft’s elevator control system in certain high-energy situations.

The ATSB’s final report (expected to be released in December this year) will provide a comprehensive analysis and findings of all areas investigated, including into maintenance issues.
 
This is a complicated investigation with several areas requiring thorough analysis.
The ATSB is disappointed that this article was published without the author seeking comment, amplification, explanation nor clarification from the ATSB in relation to this investigation.
 

 To which Martin Aubury responded: OZAUB defends his honour

On 11 July Fairfax Media published my account of the Virgin ATR 72 debacle at Plane lucky: an aviation escape. ATSB took umbrage and published a rebuttal on 14 July at https://www.atsb.gov.au/newsroom/correcting-the-record/. I stand by my article and deny it “contains factual errors and misunderstandings”.


Since ATSB is so defensive of its lengthy investigation let’s spell out the timeline and compare it with Indonesia’s investigation of the AirAsia QZ8501 accident.

On 20 February 2014 the pilots of a Virgin ATR 72 mis-handled control inputs and overloaded the tailplane by 47 percent beyond ultimate design capability. Nowadays we design aircraft precisely, with no extra strength “for Mum and the kids”. So it is pure luck that the structure held together. For the next 5 days nobody noticed serious damage and a visibly twisted tailplane. The critically weakened airliner stayed in service and carried hundreds of passengers until the damage was found largely by luck.

On 10 June 2014 ATSB published an interim report of the accident, which described the damage but not its cause or why the damage went unnoticed.

On 15 June 2016 ATSB published a second interim report which quantified the overload, explained its cause and alerted operators that inadvertent application of opposing pitch control inputs can catastrophically damage ATR 72 and ATR 42 aircraft. ATSB seems not to have warned operators of other aircraft with similar controls. And 28 months after the accident ATSB is still analysing why post-occurrence inspections failed to detect such gross damage.

Meanwhile on 28 December 2014 an AirAsia Airbus A320 crashed after a series of mistakes culminating in somewhat similar control mis-handling by the pilots. It took Indonesian investigators just 12 months to recover wreckage, extract flight data, analyse a complicated accident scenario and publish a thorough analysis of what went wrong.

ATSB must explain why its investigation is taking so long, and Virgin and CASA must be held to account for why so many passengers were put in jeopardy. Otherwise Australia’s aviation luck may run out.

So after 1174 days since this accident first occurred and 328 days since the ATSB 1st publicly identified these safety issues, the Martin Aubury 'please explain' comment is yet to be addressed and the ATSB investigation is yet to see action that effectively mitigates these safety risks...

Once again IMO it is questionable whether the ATSB has become part of the accident causal chain...


MTF...P2