February 20, 2008
U.S. Department of Transportation,
Docket Operations, M-30,
West Building Ground Floor,
Room W12-40
1200 New Jersey Ave, SE.,
Washington, DC
RE: NPRM-[Docket No. FAA-2008-0048; Directorate Identifier 2007-NM-276-AD]
RIN 2120-AA64
Dear Sir/Madame,
The Allied Pilots Association (APA) has monitored the composite-related
incidents involving Airbus aircraft since the 2001 crash of AA 587. Especially
in the cases of the AA 903 and Air Transat 961, incidents where the composite
vertical fin attachment lugs of two Airbus aircraft were cracked yet undetected
using the Airbus methods of visual and tap inspections, APA has expressed
concern about the effectiveness of the Airbus inspection philosophy.
On November 22, 2007, the Transportation Safety Board (TSB) of Canada issued its
Final Report on the Air Transat 961 rudder disintegration incident that occurred
on an Airbus 310 while en route from Cuba to Canada on March 6, 2005.
According to the summary of the report:
The TSB investigation found that the aircraft took off from Varadero, Cuba, most
probably with pre-existing damage to the rudder. The separation of the rudder
from the aircraft together with the findings of the investigation determined
that the inspection programs for this model of composite rudder are not adequate
for the timely detection of defects.
The report stated that the damaged rudder of the subject aircraft, when exposed
to the vacuum cycling that occurs in a normal ascent to altitude, caused the
internal damage in the rudder to rapidly grow until (as the report says) the
rudder ?exploded.? While the TSB mentioned several concerns, the most
significant and broad safety concern identified is that the inspection method
advocated by Airbus Industries for honeycomb sandwich composite structures (used
on flight controls on the A300, A310, A330 and A340) ?are not adequate? in
finding significant damage within the structures.
The final TSB report re-emphasized a March 2006 urgent recommendation that
repetitive Non-Destructive Inspections (NDI) be incorporated into the composite
rudder inspection
program:
...the European Aviation Safety Agency (EASA,) in coordination with other
involved regulatory authorities and industry, urgently develop and implement an
inspection program that will allow early and consistent detection of damage to
the rudder assembly of aircraft equipped with part number A55471500 series
rudders. (A06-06, issued March 2006).
In October of 2007 we were made aware of the EASA Emergency Airworthiness
Directive 2007-0266. For the first time in our knowledge, these directives
order the use of ultrasonic or thermographic inspections and also direct that
these methods be used in the repetitive inspection programs on applicable Airbus
A-300 and A-310 rudders instead of the visual and tap test primary damage
discovery program long-advocated by Airbus as sufficient for the life of the
airframe.
As you may know, APA and the Coalition of Airline Pilots (CAPA) have been on
record since 2002, citing concerns echoed by composite and inspection industry
experts that the visual and tap test inspection methods advocated by Airbus were
inadequate to find hidden damage within composite materials, calling for
repetitive ultrasonic or other effective inspection methods. These concerns
were validated again by the November 2005 discovery of hidden disbonds on the
interior of an A300 rudder at Fed Ex and again when the TSB of Canada issued
their March 2006 recommendation warning that the Airbus methods were not
effective in finding damage within rudders and putting out an urgent
recommendation for the industry to implement Non Destructive Inspections.
It is worthy to note that now the TSB of Canada is joined by the EASA and the
FAA in issuing guidance that advocates or orders required and repetitive
inspections of the affected rudders using ultrasound or infrared methods and
declaring visual inspections used in the past as ?ineffective.?
APA applauds the fact that the manufacturer and the regulatory authorities
finally recognize that the visual and tap test methods of inspection on the
affected rudders are ineffective. With the direction given by these ADs, it has
been clearly determined that ultrasonic, infrared and other sophisticated
penetrating inspection methods are effective and necessary and the ineffective
visual and tap test inspection program long-advocated by Airbus is effectively
invalid.
With this development, APA questions the time frames for compliance issued in
both the EASA 2007-0266 (Mandatory Continuing Airworthiness Information-MCAI)
and the FAA 2008-0048, specifically the requirement to conduct ?a special
detailed one time inspection? and ?a special detailed inspection along the
rudder Z-profile? within 500 flight cycles or 6 months after the effective date
of the AD. Given statements by the TSB of Canada and damage sustained by Air
Transat 961 resulting in catastrophic destruction of the rudder and damage to
the vertical fin due to unknown quantity and type of damage to the rudder that
existed, it is unclear why any tolerance period is being considered by the FAA
for repair. The affected rudders have been inspected using only visual means,
meaning that the aircraft, as they sit on the ramp, have not been inspected
using any effective means. The un-inspected A300s and A310s referenced in this
AD are, according to this understanding, in unknown condition and are therefore
presumably at risk of an in-flight incident much like what happened on Air
Transat 961. Until the condition of the rudders is discovered using ultrasonic
or thermographic means IAW the AD, APA is unclear of the rationale being used by
the EASA and the FAA to allow these aircraft to fly in the interim.
Accomplishment of the EASA and FAA directives in fact should be a requirement
for any further flight.
After the crash of American Airlines 587, an Airbus A-300 aircraft that was the
first commercial jet to crash after losing its composite vertical fin, pilot
organizations called for ultrasonic and infrared methods to be used to inspect
rudders and vertical fins on all commercial jets; their concerns were echoed by
composite and inspection experts from many quadrants, including former NTSB
experts and a composite expert from MIT. These concerns were characterized at
the time by the NTSB and Airbus as unwarranted and unnecessary; it took the
near-crash of Air Transat 961, the discovery of internal damage inside the
rudder of a Fed Ex A-300 later that same year and the frank report by the TSB of
Canada for the EASA and the FAA to conclude that the pilots and others were
right: sophisticated materials need sophisticated inspections.
Given these reformed understandings about inspection methods, we must also
question presumptions made by investigators and their conclusions in recent
incidents and accidents. Past investigations that involved composite failures
should be re-opened for further study as these directives indicate that the
history of the aircraft rudder inspections used improper, ineffective methods
and may have resulted in improper conclusions on what has turned out to be an
inadequate rudder inspection philosophy employed by Airbus. The FAA should also
insure that repetitive ultrasonic or thermographic inspection methods are
required on the next-generation aircraft that are composed of an
increasingly-larger percentage of composite materials.
In conclusion, we are pleased that the common-sense procedures the APA and CAPA
called-for in 2002 have finally been partially implemented. We urge the FAA to
consider these comments seriously so that we may improve the inspection method
effectiveness as rapidly as manufacturers are employing improved technologies on
21st century aircraft designs.
Sincerely,
First Officer Todd Wissing
National Safety Committee ?
Aircraft Design and Composites
Allied Pilots Association
This is comment on Rule
Airworthiness Directives; Airbus Model A310 and A300-600 Series Airplanes
View Comment
Attachments:
Allied Pilots Association
Title:
Allied Pilots Association
Related Comments
Public Submission Posted: 02/21/2008 ID: FAA-2008-0048-0003
Feb 21,2008 11:59 PM ET
Public Submission Posted: 02/21/2008 ID: FAA-2008-0048-0004
Feb 21,2008 11:59 PM ET