May 10, 2002
From: William W. Melvin
To: Norman Mineta, Transportation Secretary
From 1968 until 1993 when I retired, I was on the ALPA (Air
Line Pilots Association) Airworthiness &
Performance Committee and was Chairman most of that time. My Committee
was
very much involved in the structure discussions in the early 80's
when
composite materials were first being proposed for aircraft. The
FAA assured
us that composite materials would not be used as primary structure
for
transport aircraft.
In April of 1988 the top of the Aloha 737 blew off and that
caused a
considerable effort toward the assurance of continued airworthiness
of
transport aircraft. Congressman Oberstar held hearings on a bill
for aging
aircraft. In the ALPA testimony, I cannot find any reference or
concern over
the continuing airworthiness of composite structure. I believe
this is
because we were sure that composite materials would not be used
for primary
structure.
The airbus which crashed in New York was manufactured in 1988.
What tests
and methods are in place to provide assurance of continuing airworthiness
of
composite material when used as primary structure? We apparently
didn't deal
with the problem in 1988. I have read recently that Airbus is
intending to
build the entire center section of their next aircraft from composite
materials.
Metal structure has a long history of fail safe design with
the ability to
determine overload from visual and other inspections. Such is
not the case
for composite materials. You surely recall the failure of composite
structure which cost Don Engen his life. I hope we do not have
to see a
second failure on a transport aircraft to learn a lesson, as was
the case of
the Lockheed Electra wing failures and the B-727 rudder hardovers.
There may be some sophisticated means to test and determine
the continued
airworthiness of composite materials. If such a method exists
and is not
required or if one is not immediately developed and another failure
occurs
on an Airbus, the consequences to Airbus and any airline which
flies their
aircraft will be devastating.
Sincerely,
William W. (Bill) Melvin