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Darn.
I failed. Well, even better.
Six coupes that hade in-flight seperations.
We had one corroded fitting on the rear spar attachment, one already cracked
rib with a following swiss cheese AD,
Then 4 more due to overstress of the airframe.
But with NTSB Identification: LAX04FA150. it is 5 due to overstress of the
airframe
Ercoupe 415-C, registration: N93707
The fractured rivets were firmly in place and the exposed portions of the
rivet heads and tails showed no evidence of degradation from corrosion. One
of the rivet faces was examined using a scanning electron microscope and
showed intergranular features consistent with stress corrosion cracking in
aluminum alloy. An ultrasonic inspection of several of the intact and
fractured rivets did not indicate that any of the intact rivets were
cracked.
fracture faces in this area showed a matter appearance typical of a ductile
fracture. The ductile fractures were not covered with aluminum oxide.
The wing skin surface and hat sections displayed surface corrosion. The
angle brace stiffners were flaking and the corrosion had the appearance of
intergranular or exfoliation type corrosion
The front face of the cap on the left piece contained two corrosion damage
areas. The corrosion in these two areas extended between the layers of the
extruded material of the upper cap, typical of exfoliation corrosion.
Hartmut
----- Original Message -----
From: "Ed Burkhead" <[EMAIL PROTECTED]>
To: "'Hartmut Beil'" <[EMAIL PROTECTED]>; "Ctech" <[email protected]>
Sent: Thursday, February 09, 2006 7:25 PM
Subject: RE: [COUPERS-TECH] Coupes losing wings.
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advice in this forum.]----
Hartmut wrote:
The 7 reported structural failures did happen over a span of 25
years. It is not that Ercoupes fall out of the sky every other week.
Hartmut,
Actually, the count, by your excellent data, is six. You accidentally
included SEA85FA217 as your third and also as your last example.
Ed
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