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December 2013 - Quality Assurance, Do not forget it, never!

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Written by Laurence
Tuesday, 12 November 2013 16:49

The stories you will read underneath have nothing to do with Penetrant Testing, or Magnetic Particle Testing, or even, with none of the other NDT methods. However, one method could have been used, but it was not specified.


On Wednesday 11 September 1991 (yes, exactly ten years before the 9/11 events of 2001), a crash occurred in the USA. A commuter (a less-than-thirty seat plane, making back-and-forth trips between a hub and small towns) made a sharp downward pitch. Within a short time, all the 14 people aboard were killed.

The previous night, this plane went through some maintenance on the tail: several pilots had complained about the “tightness” of some rudder, pitch and roll commands.
Mechanics unscrewed part of the plane’s tail wing, replaced some of the wing, put in place the 43 screws that hold the part in place.

At this same moment, it was shift-time. The mechanics who had unscrewed the part, replaced it and put the screws in place, were replaced by another team.

The mechanics of this team, taking command of the plane under maintenance, noted that all the screws were in place. A visual inspection, and the plane was cleared for its first flight of the morning.
The plane made four back-and-forth trips without any problem, but the further flight was the flight too many.

The National Transportation Safety Board (NTSB) investigators found that the maintenance records showed mechanics unscrewed part of the plane's tail wing, replaced some of the wing and put the screws in place.

But, wait a minute: have you noticed that, twice, we wrote, “the screws (were) put in place,” but that we have not written that they had been...screwed? That was the root cause of the problem: the first shift of mechanics put the screws where they were supposed to be, but as their shift was finished, they let the screws loose, without telling the next shift. The mechanics of the next shift made only a visual inspection. No one took time at least to check with a screwdriver that the screws were tightened. This is the perfectly non-destructive testing (NDT) method that should have been used!

The information was not forwarded from the team who had not completely done the work to the next, which did not even try to check.

In many industries, focus is made on “Quality Assurance”, with many written (or computerised) reports, certificates of analyses, or of compliance to this or that standard or specific requirement.

However, Quality Assurance should also comprise the assurance that the work has been performed the right way, that all the needed pieces of information are relayed to the next operator (be it another team, another inspector, another company, etc.) to assure of the safety.

This has been well understood, along the years, in the nuclear industry, in the aerospace world, in railways, during manufacture, during maintenance, even if no NDT is performed. It is a way of thinking...that is not that often entrenched in some areas: “too costly, too time-consuming, etc.”

Another somewhat similar example occurred recently (in August 2013).
Reprinted from MRO Network (www.mro-network.com), 14 August 2013, by Joanne Perry, with authorisation.

On August 12, 2013, an easyJet A320 departing from Milan Malpensa for Lisbon made a swift about-turn shortly after take-off, following what the airline coyly described as a “technical issue” with one of its engines. Passenger reports and photographs taken on landing confirmed that the cowl on the left engine had ripped off.

After circling for 20 minutes, the aircraft landed safely using both engines, with no injuries to the 174 passengers and six crew onboard. EasyJet has said it is now investigating exactly what happened on EZY2715.

Without wishing to prejudice proceedings, though, one suspects that the investigators will not need brains of Einstein-like proportions to work out what went wrong.

A mere three months before (May 24, 2013), an A320-family aircraft operated by BA also found itself at the mercy of an engine cowl with separatist ideas, leading to an emergency landing at London Heathrow. BA’s A319 touched down with its right engine on fire, although here too everyone onboard escaped to fly again another day (post-traumatic stress disorder notwithstanding).

The subsequent Air Accidents Investigation Branch (AAIB) report listed a shocking amount of damage to the A319’s airframe and systems, noting that the event “has shown that the consequences of fan cowl door detachment are unpredictable and can present a greater risk to flight safety than previously experienced”. The AAIB concluded that the cowls had been left unlatched during overnight maintenance.

While the consequences may be unpredictable, perhaps the same cannot be said for the occurrence of such incidents. The AAIB noted that previous separation incidents have been known on A320-family aircraft. Indeed, while referencing an Airbus Safety First article on the subject, the AAIB said there had been 32 incidents of fan cowl door detachments by July 2012 – 80 per cent of which occurred during take-off.

In describing the details of BA’s A319, the AAIB made the key point that the aircraft’s nacelle has a low ground clearance which “usually requires maintenance personnel to lie on the ground to access the latches”; the latches are “difficult to see unless crouched down so that the bottom of the engine is clearly visible”.

Prior to the most recent incident, Airbus had already taken to reminding operators to adhere strictly to the aircraft maintenance manual (AMM) – but unfortunately it looks as if not everyone has been listening.

It’s surely only a matter of time before the next cowl “comes and goes”.

>> See more


A new hazard of modern times appeared: the immoderate and inappropriate use of cell phones.

Did you already see all these technicians constantly disturbed by telephone calls or calling from their cell phones?
Often a waste of time... especially when it comes to personal communications.

As an example: the phone rings and the technician forgot to tighten the bolts. And if nobody checks behind ... it could be disastrous!


In the '60s, a UK Company had a motto: ‘‘for every surface treatment problem, there is a product xxxxxx" (trademark we do not display).’’

Engineers and Commercial people in this Company had made a "translation": ‘‘with every surface treatment product xxxxxx (trademark we do not display), there is a problem.’’

This anecdote is there only to remind everyone that problems met in workshops may be due to the suppliers/manufacturers as well as to the users.

Our idea in these documents is NOT to target anyone, but on the contrary to bring to your knowledge some interesting cases which may prevent you to duplicate the same mistakes while performing Penetrant Testing (PT) or Magnetic Particle Testing (MT).

All the ministories you will read are TRUE. We think they will be helpful:

-    First as examples of specific technical - or non-technical - requirements or peculiar problems.

-    Second to let you see that the problems do not always come where you think they should come from.

-    Third so that users feel free to ask for help from people (the experts) who may know more than they do.

If you know of examples of some interest for others, please feel free to mail them to us. They will be displayed on our website as anonymously as those already published.

One's experience may help others. In addition, any interesting problem met during audits may also help: auditors, who sometimes face incredible situations and have hard times, as well as auditees may have very useful pieces of information.

We thank you in advance for any input.


 

Last Updated ( Wednesday, 05 March 2014 09:40 )