PPRuNe Forums - View Single Post - Paul Phelan’s article in The Australian on Fri 10 Aug.
Old 16th Aug 2007, 01:50
  #23 (permalink)  
Paul Phelan
 
Join Date: Jun 1999
Location: Australia
Posts: 29
I hesitate to enter a dialogue on a forum where I am anonymously accused of dishonesty, opportunism, sensationalism, ignorance of contextual issues, and onanism.

My discussions with the manufacturers’ representatives took place over 25 years ago, so their comments could not be expected to cover issues that had not become evident at that time.

The manufacturer’s representatives expressed surprise at the certification to higher weights, and asked if somebody had fitted “a couple of turbo 350s” for the flight test.

No, there is no evidence that the aircraft would not have broken up if they had been operated at a lighter weight. In fact some of the (about) 30 Shrikes which have now suffered structural failures had probably not been exposed to higher operating weights. Clearly however, higher operating weights increase the risk of a failure incurring . That is one of the two reasons why MTOWs are imposed.

As to whether the type is safe or not, a quote from Mr Swift’s treatise seems relevant. “Things are not always what they seem. Despite the robust appearance, at last count 24 Aero Commanders had lost wings in flight, 35 spars had been found cracked on the ground, and hundreds of other spars had defects caused by fatigue, corrosion, stress corrosion and static overload.” Obviously frustrated by inaction on the issue, Mr Swift exclaimed: “How was it that such fundamental structural problems were still unresolved after forty years?”

That was written in 1995. I do not understand why anybody who is interested in this issue doesn’t keep a copy of Mr Swift’s study in their office.

I have not identified a single pilot who believes that an unmodified factory standard Shrike was ever able to demonstrate a 1% engine-out climb under the certification conditions at any weight in excess of 6,750 lb. I once tried it at 6,750 and the outcome was fully consistent with the results reported by the GAF chief test pilot.

Pilots who are much more familiar with the type than I am assure me that the average airframe hours on the Shrike fleet are in the order of 25,000. This would be partly explained by their use on coastwatch and night freight operations.

As for “appropriateness”, this is a live issue which has been ignored by responsible people for a long time.

I don't plan to continue debate on this forum. If anybody wants to communicate on relevant issues my e-mail is [email protected]

(Edited only to include para breaks. T.W.)

Last edited by Paul Phelan; 16th Aug 2007 at 02:04. Reason: I omitted a paragraph
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