When a private Learjet crashes in South Dakota, USA, with star golfer Payne Stewart, investigators are under pressure to figure out how the plane strayed so far off course before crashing.
On October 25, 1999, a chartered Learjet 35 business jet was scheduled to fly from Orlando, Florida, United States to Dallas, Texas, United States. Early in the flight, the aircraft, which was climbing to its assigned altitude on autopilot, lost cabin pressure, and all six on board were incapacitated by hypoxia, a lack of oxygen in the brain and body. The aircraft continued climbing past its assigned altitude, then failed to make the westward turn toward Dallas over North Florida and continued on its northwestern course, flying over the southern and midwestern United States for almost four hours and 1,500 miles (2,400 km). The plane ran out of fuel over South Dakota and crashed into a field near Aberdeen after an uncontrolled descent.
The two pilots were Michael Kling and Stephanie Bellegarrigue. The four passengers on board were PGA golfer Payne Stewart; his agent, and former Alabama football QB, Robert Fraley;president of the agency, Van Ardan; and Bruce Borland, a golf architect with the Jack Nicklaus golf course design company.
History of the flight
Note: all times are presented in 24-hour format. Because the flight took place in both the Eastern Time zone – Eastern Daylight Time (EDT) – and the Central Time zone – Central Daylight Time (CDT) – all times are given in this article in Coordinated Universal Time (which is indicated by the time followed by the letters UTC).
On October 25, 1999, a Learjet 35, registration N47BA,[6] operated by Sunjet Aviation of Sanford, Florida, departed Orlando International Airport (IATA: MCO, ICAO: KMCO) at 13:19 UTC (09:19 EDT) on a two-day, five-flight trip. Before departure, the aircraft had been fueled with 5,300 lb (2,400 kg) of Jet A, enough for four hours and 45 minutes of flight. On board were two pilots and four passengers.
At 13:27:13 UTC, the air traffic controller from the Jacksonville Air Route Traffic Control Center (ARTCC) instructed the pilot to climb and maintain flight level (FL) 390 (39,000 feet (11,900 m) above sea level). At 13:27:18 UTC (09:27:18 EDT), the pilot acknowledged the clearance by stating, "three nine zero bravo alpha." This was the last known radio transmission from the airplane, and occurred while the aircraft was passing through 23,000 feet (7,000 m). The next attempt to contact the aircraft occurred six minutes, twenty seconds later (fourteen minutes after departure), with the aircraft at 36,500 feet (11,100 m), and the controller's message went unacknowledged. The controller attempted to contact N47BA five more times in the next 4+1⁄2 minutes, again with no answer.
First interception
About 14:54 UTC (now 09:54 CDT in the Central Time zone), a United States Air Force F-16 test pilot named Colonel Olson, from the 40th Flight Test Squadron at Eglin Air Force Base in western Florida, who happened to be in the air nearby[citation needed], was directed by controllers to intercept N47BA. When the fighter was about 2,000 feet (600 m) from the Learjet, at an altitude of about 46,400 feet (14,100 m), Olson made two radio calls to N47BA but did not receive a response. The F-16 pilot made a visual inspection of the Lear, finding no visible damage to the airplane. Both engines were running and the plane's red, rotating anti-collision beacon was on which is standard operation for aircraft in flight. Olson could not see inside the passenger section of the airplane because the windows seemed to be dark. Further, he stated that the entire right cockpit windshield was opaque, as if condensation or ice covered the inside. He also indicated that the left cockpit windshield was opaque, although several sections of the center of the windshield seemed to be only thinly covered by condensation or ice; a small rectangular section of the windshield was clear, with only a small section of the glare shield visible through this area. He did not see any flight control movement. At about 15:12 UTC, Olson concluded his inspection of N47BA and broke formation, proceeding to Scott Air Force Base in southwestern Illinois.
Third interception and escort
About 16:50 UTC, two F-16s from the 119th Wing of the North Dakota Air National Guard with the identification "NODAK 32" were directed to intercept N47BA. TULSA 13 flight also returned from refueling and all four fighters maneuvered close to the Lear. The TULSA 13 lead pilot reported, "We've got two visuals on it. It's looking like the cockpit window is iced over and there's no displacement in any of the control surfaces as far as the ailerons or trims." About 17:01 UTC, TULSA 13 flight returned to the tanker again, while NODAK 32 remained with N47BA.
There was some speculation in the media that the fighter jets were prepared to shoot down the Learjet if it threatened to crash in a heavily populated area.[citation needed] Officials at the Pentagon strongly denied that possibility. Shooting down the plane "was never an option," Air Force spokesman Captain Joe Della Vedova said, adding that "I don't know where that came from."
Canadian Prime Minister Jean Chrétien authorized the Royal Canadian Air Force to shoot down the plane if it entered Canadian airspace without making contact. He writes in his 2018 memoirs, "The plane was heading toward the city of Winnipeg and the air traffic controllers feared that it would crash into the Manitoba capital. I was asked to give permission for the military to bring down the plane if that became necessary. With a heavy heart, I authorized the procedure. Shortly after I made my decision, I learned that the plane had crashed in South Dakota." Chrétien relates that Stewart was "an excellent golfer, whom I knew and liked very much."
Crash
The Learjet's cockpit voice recorder (CVR), which was recovered from the wreckage, contained an audio recording of the last thirty minutes of the flight (it was an older model which only recorded thirty minutes of audio; the aircraft was also not equipped with a flight data recorder).At 17:10:41 UTC, the Learjet's engines can be heard winding down on the CVR recording, indicating that the plane's fuel had been exhausted. In addition, sounds of the stick shaker and the disconnection of the autopilot can be heard. With the engines powered down, the autopilot would have attempted to maintain altitude, causing the plane's airspeed to drop until it approached stall speed, at which point the stick shaker would have automatically engaged to warn the pilot and the autopilot would have switched itself off.
At 17:11:01 UTC, the Lear began a right turn and descent. NODAK 32 remained to the west, while TULSA 13 broke away from the tanker and followed N47BA down. At 17:11:26 UTC, the NODAK 32 lead pilot reported, "The target is descending and he is doing multiple rolls, looks like he's out of control... in a severe descent, request an emergency descent to follow target." The TULSA 13 pilot reported, "It's soon to impact the ground; he is in a descending spiral."
Impact occurred approximately 17:13 UTC, or 12:13 local, after a total flight time of 3 hours, 54 minutes, with the aircraft hitting the ground at nearly supersonic speed and at an extreme angle. The Learjet crashed in South Dakota, just outside Mina in Edmunds County, on relatively flat ground and left a crater 42 feet (13 m) long, 21 feet (6.4 m) wide, and 8 feet (2.4 m) deep. None of its components remained intact.
Investigation
The National Transportation Safety Board (NTSB) has several levels of investigation, of which the highest is a "major" investigation. Because of the extraordinary circumstances in this crash, a major investigation was performed.
The NTSB determined that:
The probable cause of this accident was incapacitation of the flight crew members as a result of their failure to receive supplemental oxygen following a loss of cabin pressurization, for undetermined reasons.
The Board added a commentary regarding the possible reasons why the crew did not obtain 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 into 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.
[A] 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. Research has shown that a period of as little as 8 seconds without supplemental oxygen following rapid depressurization to about 30,000 feet (9,100 m) may cause a drop in oxygen saturation that can significantly impair cognitive functioning and increase the amount of time required to complete complex tasks.
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 (3,000 m) (which could have occurred in about 30 seconds).
Investigations of other accidents 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.
The NTSB report showed that the plane had several instances of maintenance work related to cabin pressure in the months leading up to the crash. The NTSB was unable to determine whether they stemmed from a common problem – replacements and repairs were documented, but not the pilot discrepancy reports that prompted them or the frequency of such reports. The report criticised Sunjet Aviation for the possibility that this would have made the problem harder to identify, track, and resolve, as well as the fact that in at least one instance the plane was flown with an unauthorized maintenance deferral for cabin pressure problems.
Documentaries
The documentary series Mayday, also known by the titles Air Crash Investigation and Air Disasters, features this incident in the first episode of its 16th season. The episode, titled "Deadly Silence", was first aired on June 7, 2016.
Download Timer
Tags:
mayday air diaster season 16
air disasters season 17 release date
air disasters season 16 episode 4
air disasters season 16 episode 1
air disasters season 16 episode 9
air disasters season 16 episode 5
season 16 air disasters
is mayday and air disasters the same
is mayday air disasters on hulu
mayday season 16 episode 6
mayday air disasters season 1
season 17 air disasters
mayday air disaster season 21
air disasters season 16 episode 3
air disasters season 16 episode 7
how many seasons of air disaster are there
is mayday an acronym
air disasters season 16 episode 10
what channel is mayday air disaster on
mayday air disaster where to watch
where can i watch mayday air crash investigation
why mayday is called mayday
why mayday distress call
why mayday is used
why mayday for emergency
why is air disasters season 1 unavailable
mayday air disaster season 2
wonder mayday series
wonder mayday air disaster
mayday air diaster season 16
mayday air disaster season 21
mayday air disaster season 1
mayday season 16 episode 6
air disasters season 16 episode 4
air disasters season 16 episode 10
air disasters season 16 episode 7
air disasters season 16 episode 9
air disasters season 16 episode 2
mayday air disasters season 1
season 16 air disasters
air disasters season 16 episode 5
air disasters season 16 episode 3
mayday air crash investigation season 16
what channel is mayday air disaster on
dal airport delays today
air disasters season 17 release date
watch air disasters season 16
air disasters season 16 episode 1
mayday air disaster season 2
mayday season 1 episode 3
should i turn on ac when air quality is bad
mayday season 18 episode 7
air crash investigation season 16
mayday air crash investigation season 16
air crash investigation season 16 episode 3
air crash investigation season 16 episode 7
air crash investigation season 16 episode 8
air crash investigation season 16 episode 1
air crash investigation season 16 watch online
air crash investigation season 16 episode 5
best episodes of air crash investigation
air crash investigation list of episodes
air crash investigation season 16 bilibili
best air crash investigation
csi crime scene investigation season 16 episode 1
csi crime scene investigation season 16 episode 2
air crash investigation season 16 episode 4
air crash investigation season 16 download
list of mayday air crash investigation episodes
air crash investigation season 16 episode 10
air crash investigation season 16 episode 9
air crash investigation season 16 episode 6
air crash investigation season 16 episode 2
air crash investigation season 15 episode 3
air crash investigation season 18 episode 1
air crash investigation season 19 reddit
air crash investigation s16
air crash investigation season 15 episode 1
air crash investigation how to watch
air crash investigation season 21 release date
air crash investigation season 16 reddit
us air crash investigation
us air force accident investigation reports
us air crash in pittsburgh
us air crash in charlotte
air crash investigation s16e07
air crash investigation season 16 123movies
air crash investigation season 16
air crash investigation season 16 episode 2
air crash investigation season 16 episode 3
criminal minds season 16 air date
air crash investigation season 15 episode 3
air crash investigation season 18 episode 1
air crash investigation s16
has air disasters been cancelled
air crash investigation season 16 episode 7
season 16 air disasters
mayday season 16 episode 6
air crash investigation season 18
where to watch air crash investigation season 21