At least five of six lugs, or attachment points, from American Airlines Flight 587 will undergo testing to further define sub-surface damage.
Posted on 03/20/2002 7:32:40 AM PST by Rokke
FRANCES FIORINO/NEW YORK
An FAArequest for additional inspections of Airbus A300-600 vertical stabilizers could come as early as this week pending results of an evaluation of the aircraft's service history data now underway.
At least five of six lugs, or attachment points, from American Airlines Flight 587 will undergo testing to further define sub-surface damage. |
The agency and Airbus are "working swiftly" to complete their review to identify -600s involved in "maneuver events or upsets" with unusually high lateral loads that may have damaged the composite tail, according to the FAA.
Any "order" for inspection of suspect vertical stabilizers would focus on A300-600s, excluding early models with metal tail fins--A300B2s and A300B4s--but would not come in the form of an airworthiness directive, said FAA spokesman Les Dorr.
OPERATORS MIGHT VOLUNTARILY inspect aircraft, or the manufacturer could issue an All Operators Telex (AOT), which Airbus describes as information sent to customers that does not necessarily require action.
According to Airbus, criteria for identifying aircraft include examination of lateral load experiences and flight data recorder (FDR) information back to date-of-entry into service, with the review expected to yield "a very small, very targeted group of aircraft that require inspection."
Inspection criteria have not been defined by the FAA or Airbus, but once the target group is identified, Airbus plans to pull the tails and perform an ultrasonic test as a safety precaution. Not one of the six aircraft (three U.S.-based; three international) Airbus anticipates checking has approached ultimate load, according to an Airbus-North America official.
There are 100 -600s in service in the U.S. American Airlines operates 34 in passenger service, and FedEx and UPS utilize the remaining as cargo carriers.
The FAA says the study of aircraft service histories could also reveal whether pending inspections might involve other types of aircraft, such as the Airbus A310, which has a similar tail structure.
Concerns about the A300's vertical stabilizer emanate from the National Transportation Safety Board's ongoing investigation of the Nov. 12, 2001, crash of American Airlines Flight 587, in which the tail was ripped from the aircraft within minutes of its departure from New York John F. Kennedy International Airport.
Airbus, in a Mar. 11 statement, said it is "aware of only one event that involves loads approaching in severity those encountered in the accident of Flight 587"--American Airlines Flight 903, N90070 (Serial No. 513), A300B4-605R.
On May 12, 1997, Flight 903 stalled in a right turn at 16,000 ft. approaching Miami. The pilot applied full left rudder and reversed the rudder at least once in recovery. The aircraft experienced sudden pitch, yaw and roll movements with flight control oscillations lasting 34 sec., and lost 3,000 ft. altitude. The NTSB said the crew did not "use proper stall recovery techniques." One person was injured seriously and the -600 sustained minor damage ( AW&ST Mar. 4, p. 52).
The NTSB and Airbus recently ordered an inspection of Flight 903's vertical stabilizer, which entailed removal of the tail and a special nondestructive ultrasonic test to determine its structural integrity.
THE NTSB SAID RESULTS of the Flight 903 inspection, performed at the American Airlines maintenance facility in Tulsa, Okla., showed "an indication of damage, possibly delamination," at the pin bushing of the right rear lug, which "apparently was not present at time of manufacture."
Airbus, in its Mar. 11 statement, said the stabilizer on the -600 features a "fail-safe design and is certified to safely withstand flight load levels" with one of the six attachment bolts missing. Airbus further points out that the damage to Flight 903 did not entail this type of damage and that the aircraft continued to operate safely. Additional tests of the vertical stabilizer will be conducted to analyze the component's behavior in extreme operating conditions.
Some industry observers think the vertical stabilizer problems will pull the rug out from under Airbus' design and inspection philosophy.
Also in its Mar. 11 statement, Airbus states it "is confident in the current design and inspection philosophy for the vertical stabilizer of aircraft operating within the certification envelope, according to which no additional testing is required, unless visible damage is detected."
If, in the future, however, an aircraft is found to have experienced loads in excess of certification limits, the manufacturer said it "will apply similar procedures to the one applied on aircraft No. 513 [Flight 903]" on a case-by-case basis.
The NTSB, in its AA587 accident update of Mar. 11, said Flight 903 "experienced high lateral loads associated with reversing rudder movements during the 1997 accident."
Flight 903 had "a load experience beyond ultimate load," or 1.5 times design limit load as defined in FAR 25, according to the Airbus spokesperson.
Critics point out that Flight 903 was only given the special inspection five years after the event, and the airframe passed the visual inspection following the 1997 upset and the one required by the emergency airworthiness directive 2002-23-51 issued Nov. 16, 2001, following the crash of Flight 587. This brings into question the ability of visual inspections to detect damage caused by high airloads.
There is also the question of how officials will determine which aircraft have sustained high lateral loads. Flight 903 was traceable because a serious injury was involved that prompted an investigation, the pulling of the FDR and storing of its data. "Are they going to look at the FDR traces of every flight?" one critic asked. "Are they even available?"
One official close to the AA587 investigation said it is likely some Flight Operations Quality Assurance Programs data might be used in addition to FDR traces--the latter of which are not readily available "unless there is a reason to keep it."
THE NTSB POINTS OUT it is currently evaluating a May 1995 incident in which a FedEx A300 experienced "large rudder deflections, not reversals, as a result of a rudder trim/autopilot interaction." According to the Airbus spokesman, the FedEx -600 was 0.8 times the limit load.
A FedEx spokesman told Aviation Week & Space Technology that a malfunction of a component caused a "single swing of rudder" in the 1995 event. There were no injuries to the crew, nor was there damage to the aircraft. The event was duly noted in the service report, and the aircraft inspected according to Airbus guidelines and returned safely to service.
The aircraft in the 1995 event is not to be confused with the FedEx -600 that in late January was discovered to have minor structural damage on the rudder. That rudder was removed and is to undergo further testing, according to the NTSB.
Meanwhile, destructive testing of small composite samples removed from Flight 587 is underway at a NASA facility in Hampton, Va.
The lugs or attachment points between the stabilizer and the empennage will undergo CT-Scan testing to define any sub-surface damage. The left rear and left front lugs are destined for Lawrence Livermore National Laboratory in California and the right rear, center and front lugs for Aberdeen Proving Ground in Maryland. (The lugs are attached to various-sized pieces of wreckage. The size of the piece determines it destination; Livermore is able to handle larger pieces.) The destination of the left center lug remains undetermined.
© March 18, 2002 The McGraw-Hill Companies Inc.
Any "order" for inspection of suspect vertical stabilizers would focus on A300-600s, excluding early models with metal tail fins--A300B2s and A300B4s--but would not come in the form of an airworthiness directive, said FAA spokesman Les Dorr.What they are saying is that they would like to make a show of looking for a defect without actually putting anyone's credibility on the line.
...Let's see now...
...November, December, January, February, March and we STILL DON'T have a difinative answer as to the actual cause of the New York Crash of a French A300 Jetliner last Veterans Day Weekend...?
...I flew twice cross-country on A-300's last month for our Battle of IA DRANG-1965 Vets Special Ft. Benning Screening of .."WE WERE SOLDIERS".. and they seem like a terrific Jetliner to me. Nicer than the Boeing 757's I flew on over last Veteran's Day Weekend to Washington DC to honor our recently fallen IA DRANG-1965/World Trade Center-2001 Brother ..RICK RESCORLA.. at our Annual IA DRANG Alumni Dinner and at The Vietnam Wall at dawn the next morning. Just 5 hours after I landed back home ..this A-300 went down in New York = Little TV Coverage of Veterans Day Events.
..'Dateline NBC'.. was there to cover our Events in his Honor and will air its ..RICK RESCORLA.. Lifetime Lifesaver Story tonight at 8pm Eastern/Pacific Time on the full NBC-TV Network.
...While singing .."GOD BLESS AMERICA".. to those whose safety he was in charge of ..RICK RESCORLA.. saved many lives at our Battle of IA DRANG-1965 ("WE WERE SOLDIERS") and in the World Trade Center's 1993 Bombing and 2001 Airstrike on Tower 2 ..giving up his own life for others on Sept 11th.
May GOD always Bless our Protectors at Home and Away in a new -Time of War- in a new Century with an Enemy that is now Within.
NEVER FORGET
That looks suspicious, let's put the de-spin-erator on it:
"Also in its Mar. 11 statement attempting to protect it's Euro-socialist-sub-standard product, Airbus states it "is confident wary in the current design and inspection philosophy paper-mache construction for the vertical de-stabilizer of aircraft operating within the certification envelope, in dead-straight trim in calm air according to which no additional testing expense is required, unless visible damage is detected the whole tail falls off in flight - again."
Whew, I feel safer about those Airbuses now. </sarcasm>
Hell, even the damn terrorists knew that rule!
You left out a critical word - "yet"
Stress damage is cumulative, it builds up through several "minor" incidents. It's hard to see in most cases and nearly impossible to asses in large composites unless you do scan it. Even then it's not entirely clear cut.
It is entirely possible that we've seen the first of a series and I doubt such a series would have to be very long to amount to a true catastrophe.
Admitting to a partisan bias, it just seems to me that good engineering practices disallow a composite/metallic fastner joint on a critical load bearing, stress prone, fuselage joint...Oh, a critical fuselage joint with a couple hundred souls inside!
Yes indeed, and I believe it was being flown by the ranking pilots from Airbus and Air Chance, respectively. Hell of a neat way to sell a new airplane - drive it in the dirt right in front of the grandstand. And speaking of software bugs, ever notice how ALL incidents involving Airbus machines going stupid disappear and or are ascribed to pilot error? The media has always given Airbus a pass on these incidents because the cheeze-eating surrender monkeys are big members of the commie euro-trash affinity group. So they build plastic airplanes and a few people get killed - hey, not to worry.
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