ATR72 pitch disconnect warning

[Philip Argy]

The ATSB yesterday issued a safety-triggered interim report after discovering that the risk of inadvertent flight inputs causing catastrophic structural damage is much higher than had been assumed:

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.

View the interim report at In-flight pitch disconnect involving ATR 72 aircraft, VH-FVR, 47 km WSW of Sydney Airport, NSW on 20 February 2014

A bit disconcerting really considering the number of times I fly the SYD-CBR corridor in an ATR 72 (and FVR in particular)!

[Philip Argy]

The ATSB has issued a second interim report confirming its concerns about the tail strength of ATR 72s in the event of a pitch disconnect:

In-flight pitch disconnect involving ATR 72 aircraft, VH-FVR, 47 km WSW of Sydney Airport, NSW on 20 February 2014

If nothing is done in the next 90 days I'd say there's a possibility that the aircraft could have its certification withdrawn - pretty serious stuff!

Here's an extract:

During the continued investigation of the occurrence, the ATSB has obtained an increased understanding of the factors behind this previously identified safety issue. This increased understanding has identified that there are transient elevator deflections during a pitch disconnect event that could lead to aerodynamic loads that could exceed the strength of the aircraft structure.
The ATSB also found that these transient elevator deflections were not identified, and therefore not considered in the engineering justification documents completed during the aircraft type’s original certification process. The ATSB considers that the potential consequences are sufficiently important to release a further interim report prior to completion of the final investigation report.

[Robert.M]

Picked up by The Canberra Times
http://www.canberratimes.com.au/busi...05-gvz064.html

[Philip Argy]

I think that's an inappropriate post, Liam, in the context of an ATSB report about a potential design flaw in an aircraft - it has nothing to do with the carrier!

[Rowan McKeever]

I completely agree with Philip, and I'll add that at no point has the skill, training or professionalism of the crew, nor their specific handling of this incident, ever been called into question by the ATSB or anyone else suitably qualified to do so. So the link to human factors is tenuous at best.


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[Mick F]

Originally Posted by Liam C

Virgin's attitude toward safety (having worked for them), leaves me in no doubt that flying on those aircraft would involve some risk......

Sorry - but I (and a few others I know) are happy to stand by that !

And a very silly thing to say in a public forum as a former/current employee. Unless you're willing to go through the legal battle to back it up Liam might I suggest that you remove that.

Mick

[MarkR]

Originally Posted by Liam C

That said, I feel my point is worth making nonetheless due to the apparent systemic attitude toward safety in that airline.

I don’t think it’s a relevant point at all given from what I can gather you are talking about Virgin Blue and this was Virgin Australia Regional Airlines operating under a different AOC and staffing. After all we are talking about the same airline that had such a big concern over safety they they conducted drug testing of a crew in full view of pax preflight at bdb some time ago!

If you think you have valid concerns about a risk still evident, I would suggest a Repcon report would be in more order than alleged slander on a public forum.

[Philip Argy]

The ATSB's final and very extensive report has now been released and can be downloaded from https://www.atsb.gov.au/media/577635...-032_final.pdf.

Whilst the risk of undetected structural damage in ATR72s has been reduced as a result of ATSB-recommended inspections in an earlier interim report, the ATSB remains of the view that ATR72s in current operation globally remain subject to the unacceptable risk of foreseeable inadvertent conflicting pitch inputs from PF and PNF triggering a pitch disconnect and subsequent momentary loads on the tailplane that it was not designed to withstand. This catastrophic condition can occur below VMO and therefore within the normal operating envelope for the aircraft.

The question is, how great is that risk and would you fly in that aircraft? ATR has been asked to carry out an evaluation to quantify the risk and meanwhile we are apparently all supposed to take the risk that nothing untoward will happen.

This is a more difficult decision that whether to fly on a Boeing 737 MAX because it will undergo re-certification with its new software whereas the ATR72s are currently operating with a newly-identified risk that has not been the subject of any certification re-evaluation.

The ATSB's French counterpart, incidentally, disagrees with the ATSB's assessment of the gravity of the situation and its own comments are attached at the back of the ATSB report.

This is a very thorough report by the ATSB and it has maintained its views despite apparent disagreement from ATR and the French regulator.

I hope ATR and European regulators take this report more seriously! Our own regulator, not to mention Virgin Australia Regional Airlines, will also have some soul-searching to do.

We certainly haven't heard the last of this methinks.