just trying to clean out some old research thats been hiding away in my files...
the accident report for stewart's crash:
http://libraryonline.erau.edu/online-full-...fs/AAB00-01.pdfrandom excerpts that i found noteworthy:
In its review, the FAA found that the Learjet Model 35/36 AFM does not have an emergency
procedure requiring the flight crew to don oxygen masks immediately after the cabin altitude aural
warning is activated. Because the AFM contains an abnormal procedure allowing the flight crew to
troubleshoot the pressurization system before donning oxygen masks, the FAA noted that the flight crew
may delay donning oxygen masks and become incapacitated.
FLIGHT CREW’S FAILURE TO RECEIVE SUPPLEMENTAL OXYGEN
Following the depressurization, the pilots did not receive supplemental oxygen in sufficient time
and/or adequate concentration to avoid hypoxia and incapacitation. The wreckage indicated that the
oxygen bottle pressure regulator/shutoff valve was open on the accident flight. Further, although one
flight crew mask hose connector was found in the wreckage disconnected from its valve receptacle (the
other connector was not recovered), damage to the recovered connector and both receptacles was
consistent with both flight crew masks having been connected to the airplane’s oxygen supply lines at
the time of impact. In addition, both flight crew mask microphones were found plugged in to their
respective crew microphone jacks. Therefore, assuming the oxygen bottle contained an adequate supply
of oxygen, supplemental oxygen should have been available to both pilots’ oxygen masks.
The Safety Board evaluated several explanations for the flight crewmembers’ failure to receive
supplemental oxygen, including an inadequate quantity of oxygen or improper servicing of the oxygen
bottle and the failure (or inability) of the pilots to don their oxygen masks rapidly enough following the
loss of cabin pressure.
Oxygen Quantity
Investigators considered the possibility that there might have been an insufficient quantity of
oxygen on board the accident flight to sustain the flight crewmembers while they addressed the
depressurization. The oxygen bottle was found empty. Witness marks on the cockpit oxygen pressure
gauge caused by the impact were consistent with an indication of no pressure in the oxygen bottle.
A Sunjet Aviation official stated to the Safety Board that the accident captain had reported that
the oxygen pressure gauge was in the green zone, indicating adequate pressure of 1,550 to 1,850 psi,
during preflight checks on the day of the accident. The airplane’s maintenance records indicate that the
oxygen bottle was last serviced with oxygen (by Sunjet Aviation) on September 3, 1999. Between this
date and the date of the accident flight, Sunjet Aviation operated the airplane for about 104.6 flight
hours, on 90 flights. The Board was unable to determine exactly how many of these flight hours were
above 35,000 feet,59 but ATC voice tapes from one of the flights60 indicated that the airplane was
cleared to FL 370 on one leg. Although no radar data for that flight were available, the Board estimated
(using ground speed and distance) that the airplane would have cruised above 35,000 feet for at least
30 to 40 minutes during that round trip flight. The captain from that flight told investigators that when the
airplane was above 35,000 feet during that flight, he used supplemental oxygen. Board calculations
indicated that the flight crew’s reported oxygen usage that day would have depleted the airplane’s
oxygen supply by up to 14 to 25 percent, depending on which mask was used. Even though oxygen use
was required on this flight (and perhaps others) and was reported to have been used, the Board is
aware that pilots do not always use oxygen when required by regulation.
The Safety Board contacted fixed-based operators (FBO) at 15 known destination airports
visited by the accident airplane between September 26 and October 20, 1999, and none had any
record of charges for oxygen servicing of the accident airplane. However, the Board cannot exclude the
possibility that the airplane was serviced with oxygen after September 3, 1999, at a different airport or
at no charge to Sunjet Aviation61 and that no record was made.62
However, even if the oxygen bottle had been full at the beginning of the accident flight, the
oxygen supply would have been completely depleted before impact because the Rogers regulator
installed on one of the two flight crew masks would have automatically supplied 100 percent oxygen
when the cabin altitude increased beyond 39,000 feet. This oxygen would have been released at
130 liters per minute at a pressure of approximately 0.5 psi even if the mask was not being worn by a
flight crewmember, depleting a fully charged oxygen bottle in about 8 minutes. Therefore, the
postimpact reading on the oxygen pressure gauge is not necessarily indicative of an inadequate
predeparture oxygen supply on the accident flight.
In summary, the Safety Board could not determine the quantity of oxygen that was on board the
accident flight.
Oxygen Quality
If the airplane’s oxygen bottle had been improperly serviced with air, rather than oxygen, there
would have been insufficient partial pressure of oxygen in the supplied mixture to avoid hypoxia at high
cabin altitudes after a depressurization. The Safety Board is aware of an accident involving pilot
incapacitation from hypoxia as a result of improper servicing of an oxygen bottle with compressed air.63
The oxygen source from which the accident airplane’s oxygen bottle was serviced on September 3,
1999, was tested after the accident and found to contain 99.8 percent pure oxygen. However, because
of the possibility that the oxygen bottle might have been serviced elsewhere after that, the Board could
not rule out the possibility that the oxygen bottle contained air instead of oxygen.
Timeliness in Donning Oxygen Masks
Another possible explanation for the failure of the pilots to receive emergency oxygen is that
their ability to think and act decisively was impaired because of hypoxia before they could don their
oxygen masks. No definitive evidence exists that indicates the rate at which the accident flight lost its
cabin pressure; therefore, the Safety Board evaluated conditions of both rapid and gradual
depressurization.
If there had been a breach in the fuselage (even a small one that could not be visually detected
by the in-flight observers) or a seal failure, the cabin could have depressurized gradually, rapidly, or
even explosively.64 Research has shown that a period of as little as 8 seconds without supplemental
oxygen following rapid depressurization to about 30,000 feet may cause a drop in oxygen saturation
that can significantly impair cognitive functioning and increase the amount of time required to complete
complex tasks.65
A more gradual decompression could have resulted from other possible causes, such as a
smaller leak in the pressure vessel or a closed flow control valve. Safety Board testing determined that a
closed flow control valve would cause complete depressurization to the airplane’s flight altitude over a
period of several minutes. However, without supplemental oxygen, substantial adverse effects on
cognitive and motor skills would have been expected soon after the first clear indication of
decompression (the cabin altitude warning), when the cabin altitude reached 10,000 feet (which could
have occurred in about 30 seconds).
Investigations of other accidents66 in which flight crews attempted to diagnose a pressurization
problem or initiate emergency pressurization instead of immediately donning oxygen masks following a
cabin altitude alert have revealed that, even with a relatively gradual rate of depressurization, pilots have
rapidly lost cognitive or motor abilities to effectively troubleshoot the problem or don their masks shortly
thereafter. In this accident, the flight crew’s failure to obtain supplemental oxygen in time to avoid
incapacitation could be explained by a delay in donning oxygen masks of only a few seconds in the case
of an explosive or rapid decompression or a slightly longer delay in the case of a gradual
decompression.
In summary, the Safety Board was unable to determine why the flight crew could not, or did
not, receive supplemental oxygen in sufficient time and/or adequate concentration to avoid hypoxia and
incapacitation.
PROBABLE CAUSE
The National Transportation Safety Board determines
the probable cause of this accident was
incapacitation of the flight crewmembers as a result of their failure to receive supplemental oxygen
following a loss of cabin pressurization, for undetermined reasons.
***
UPDATES - not directly related to the above, but for posterity:
"FAA: Pilots of Stewart's Plane Had False Records"
http://abcnews.go.com/Sports/story?id=99914&page=1QUOTE
A manager with the company that owned the Learjet in which golfer Payne Stewart and five others died in a 1999 crash falsified training records for the pilots, the Federal Aviation Administration said.
This marks the first time the government has publicly accused anyone of wrongdoing in connection with the crash on Oct. 25, 1999. The FBI and Transportation Department are still investigating.
The families of Stewart and three other victims also have sued the plane's owner and operator.
Stewart died on a flight from Florida to Texas four months after winning his second U.S. Open and one month after helping the United States win back the Ryder Cup.
Company Records Were Seized
FAA lawyer Raymond Veatch told a federal administrative judge Tuesday that James Watkins Sr. of SunJet Aviation filed false records about the amount of time he had spent training pilot Michael Kling and co-pilot Stephanie Bellegarrigue.
The revelation came during a National Transportation Safety Board hearing into whether Watkins, chief pilot for SunJet and father of the company president at the time of the crash, should permanently lose his license to fly.
Company Records Were Seized
FAA lawyer Raymond Veatch told a federal administrative judge Tuesday that James Watkins Sr. of SunJet Aviation filed false records about the amount of time he had spent training pilot Michael Kling and co-pilot Stephanie Bellegarrigue.
The revelation came during a National Transportation Safety Board hearing into whether Watkins, chief pilot for SunJet and father of the company president at the time of the crash, should permanently lose his license to fly.
Dozens of agents seized almost all the company's business records at its headquarters at Orlando Sanford Airport last April.
Watkins' son, James Watkins Jr., has repeatedly said SunJet, which has since been sold, was not responsible for the crash.
On Tuesday, Administrative Judge William Pope asked Veatch if the elder Watkins had anything to do with the crash.
"He falsified documents," Veatch said. "He had been complicit in some of the wrongdoing by SunJet."
Pilot Certified to Fly Learjet One Month Before Crash
The FAA will present evidence that Watkins falsified the training records of six other pilots and should be permanently grounded, Veatch said.
Robert Leventhal, Watkins' defense attorney, argued that Kling and Bellegarrigue received the proper training from Watkins.
"Those pilots were exceptionally well-trained," he said, adding accusations that his client falsified training records are "a pile of baloney."
The NTSB has concluded the cabin lost air pressure, something that likely caused the crew and passengers to pass out soon after takeoff. The plane flew on autopilot for several hours before crashing into a pasture in South Dakota.
Kling, 42, a former Air Force pilot, had thousands of hours of experience. However, he had received his government certification to fly the Learjet only about a month before the crash.
Bellegarrigue, 27, had been cleared to fly Learjets six months before the crash.
"FAA relies on pilots to oversee other pilots"
http://archives.californiaaviation.org/pilot/msg00006.htmlofficial response timelines as told in this article:
Golfer Payne Stewart Dies in Jet Crash
By Edward Walsh and William Claiborne
Washington Post Staff Writers
Tuesday, October 26, 1999; Page A1 http://www.washingtonpost.com/wp-srv/natio...t99/crash26.htmQUOTE (excerpt)
MINA, S.D., Oct. 25—A Learjet carrying professional golfer Payne Stewart and at least four others streaked uncontrolled for thousands of miles across the heart of the country today, its occupants apparently unconscious or already dead, before it plunged nose first and crashed in a field near this north-central South Dakota hamlet.
No one on the ground was hurt and there were no survivors aboard the aircraft, which came down in a marshy area about two miles southwest of here.
The cause of the uncontrolled flight and crash after the Learjet 35 apparently ran out of fuel were not known, but aviation experts speculated that the aircraft may have lost pressurization and that emergency backup systems failed as the plane's autopilot kept it in the air. Loss of pressurization above 30,000 feet would cause occupants of the aircraft to lose consciousness from oxygen deficiency in one to two minutes, the experts said.
During some of its eerie, almost four-hour journey from Orlando to a swampy grassland in South Dakota, the Learjet was shadowed by Air Force and Air National Guard jet fighters, whose pilots reported that the aircraft's windows were frosted over, suggesting that it had lost pressurization. The Air Force pilots also reported that the Learjet meandered from as low as 22,000 feet to as high as 51,000 feet, but never strayed from a northwest heading.
The military aircraft were not armed with air-to-air missiles, and Pentagon officials said they never considered shooting down the Learjet.
"The [Federal Aviation Administration] said this thing was headed to a sparsely populated part of the country, so let it go," a senior defense official said.
According to the FAA, the plane left Orlando, where Stewart lived, at 9:19 a.m. Eastern time today and was bound for Dallas. Stewart, a two-time U.S. Open champion, was scheduled to play later this week in the PGA Championship in Houston, the tour's final event of the year.
The FAA said air traffic controllers lost radio contact with the plane at 9:44 a.m., just after they had cleared the twin-engine jet to climb to 39,000 feet northwest of Gainesville, Fla. An FAA spokesman said that air traffic controllers noted "significant changes in altitude" by the plane, but that the aircraft's crew did not respond to repeated radio calls from the ground.
Pentagon officials said the military began its pursuit of the ghostly civilian aircraft at 10:08 a.m., when two Air Force F-16 fighters from Tyndall Air Force Base in Florida that were on a routine training mission were asked by the FAA to intercept it. The F-16s did not reach the Learjet, but an Air Force F-15 fighter from Eglin Air Force Base in Florida that also was asked to locate it got within sight of the aircraft and stayed with it from 11:09 a.m. to 11:44 a.m., when the military fighter was diverted to St. Louis for fuel.
Fifteen minutes later, four Air National Guard F-16s and a KC-135 tanker from Tulsa were ordered to try to catch up with the Learjet but got only within 100 miles. But two other Air National Guard F-16s from Fargo, N.D., intercepted the Learjet at 12:54 p.m, reporting that the aircraft's windows were fogged with ice and that no flight control movement could be seen. At 1:14 p.m., the F-16s reported that the Learjet was beginning to spiral toward the ground.
The Learjet 35 is a pressurized aircraft that also is equipped with individual emergency oxygen masks for the passengers and crew if the pressurization system fails above about 12,000 feet.
Tom Baum, a Learjet pilot instructor, told CNN that a panel light in the cockpit of the plane goes on if there is a problem with the pressurization and that a backup system should then automatically begin to function. He said Learjet pilots are required to wear oxygen masks around their necks.
In nearby Aberdeen, South Dakota Highway Patrol Sgt. Scott Wherry said he and other troopers were alerted that the aircraft was headed their way. They went outside their headquarters and spotted the jet in the air.
"It appeared to be flying not in a straight line," Wherry said. "It was wavering. You could see by its trail it was not going in a straight line. Then it headed straight down, nose first."
Terry Jundt, who came upon the aircraft wreckage while on horseback in this sparsely populated region, said, "They are going to have a hard time finding anything or anybody in there."
9/11 commission Richard Myers interview (2004) makes reference to stewart crash:
http://media.nara.gov/9-11/MFR/t-0148-911MFR-00751.pdfQUOTE
Myers was asked if during his tenure as CINCNORAD anyone in NORAD ever
postulated an air breathing terrorist threat of any kind. He responded "no, not to my
knowledge, never." Myers was also not aware of any exercises during his tenure that
postulated the use of suicide aircraft. That would have raised the ROE (rules of engagement)
issue, he said, which only came up in connection with the Payne Stewart aircraft.
"I don't recall ever doing anything vis a vie terrorists or any of that business - it would
have raised this whole ROE - I might be-mistaken and I just don't remember, or maybe
it was happening and I didn't know about it - but I doubt it."
In the case of Payne Steward, NORAD requested authorization from Washington - from
the President to shoot down the aircraft before it flew into a major city. Myers recalled
that such authority was granted, but the issue became moot when the aircraft went down
in a field.
Myers could not recall any involvement in air space controls associated with National
Security Special Events (e.g., Atlanta Olympics, NATO so" Anniversary, Genoa G-8).
Myers was asked about the 1998 PDB that explicitly referenced an aircraft laden with
explosives crashing into a city. Myers stated, "it doesn't ring a bell- not at all." He also
reaffirmed no recollection of any postulated threat scenario involving a terrorist using an
aircraft as a bomb. Myers had no explanation for why other agencies - such as the Secret
Service - were thinking. of the possibility of an air threat to the White House while the
entity charged with air defense of the nation was not thinking of a threat to the National
Capitol Region.
In a hijacking situation, the FAA would call upon NORAD to (1) follow the target (2)
describe the actions the target was taking (3) and be in proximity if the target crashed.
An example would be NORAD's involvement in the Payne Stewart incident. Myers
stated that NORAD controllers would vector the fighter, but acknowledged that from a
communications standpoint it would require a great deal of coordination with the FAA.