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I extended my search to Alons and found 2 more that separated in-flight. Sad
to read all this.
Both were caused by overstressing due to aerobatic maneuvers. We are at 9
in-flight separations now since 1980.
NTSB Identification: LAX94FA367, Aircraft: ALON A2, registration: N37698
DURING A LOCAL AREA PERSONAL FLIGHT, THE PILOT PERFORMED AN AEROBATIC
MANEUVER....
EXAMINATION OF THE LEFT AILERON AND LEFT WING STRUCTURE REVEALED PERMANENT
DEFORMATION IN AN UPWARD (POSITIVE) DIRECTION. FAA AIRWORTHINESS AND
CERTIFICATION OFFICE PERSONNEL REPORTED NO SIGNS OF A DEVELOPING OR
PREEXISTING CONDITION WHICH INDUCED FAILURE OF THE SEPARATED LEFT WING TIP.
NTSB Identification: FTW88DRD20 , Aircraft: ALON A2A, registration: N5626F
THE HIGHLY MODIFIED AIRPLANE WAS OBSERVED IN A NEAR VERTICAL DIVE BEFORE IT
IMPACTED INTO A MARSH.
THE PURPOSE OF THE FLIGHT, REPORTEDLY, WAS TO PERFORM AEROBATIC MANEUVERS.
Hartmut
----- Original Message -----
From: "Hartmut Beil" <[EMAIL PROTECTED]>
To: "Ctech" <[email protected]>
Sent: Thursday, February 09, 2006 8:13 PM
Subject: Re: [COUPERS-TECH] Coupes losing wings.
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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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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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