AOPA video warns of hypoxia dangers after Citation V crash

APOA GlobalAir.com ^ | June 8 2023 | Haley Davoren

[texas booster]

On Sunday a Cessna Citation V was flying around the restricted airspace over Washington D.C. and not responding to radio communications, leading to multiple F-16 jets scrambling to intercept the aircraft before it ultimately crashed near the George Washington National Forest in southern Virginia. The AOPA released its early analysis of the deadly crash, delving into the possible causes like hypoxia.

The Citation took off from Elizabethton Municipal Airport (0A9) in Tennessee for Long Island MacArthur Airport (ISP) in New York but never descended and rather stays at the same altitude and turns around for Elizabethton. The pilot was 69 years old and a retired Southwest Airlines pilot. He flew in class one medical and was ATP-rated, the highest rating a pilot can achieve in their career. The pilot had recently passed his class one in October 2022. The jet was a Citation V, manufactured in 1990.

“The Citation jet class has an exceptional safety record and the Citation V is also a safe aircraft,” said Richard McSpadden, Senior VP of AOPA Air Safety Institute.

McSpadden notes that the jet had no known anomalies and the weather would not have been a factor leading to the crash. A point of concern is when the jet turned around once it reached its destination, indicating that the pilot may not have been conscious or responsive by that time. He said the jet turning around was most likely a type of default mode in the autopilot.

The ATC was communicating with the pilot when he left Elizabethton. He called to pick up his clearance, was cleared as filed and then after a few intermediate altitudes, he levels off at 340 or 34,000 feet, despite filing at 390. ... likely indicates he had programmed this into the autopilot from one of the clearances given.

[texas booster]

The communications essentially end once the jet reaches an altitude of 34,000 and nothing is heard until communications on guard and the intercept communications when the jet flies into Virginia. The pilot was most likely conscious up until 340, cruising at this altitude rather than the 390 filed. There was no attempt to descend into MacArthur before the jet turned around back to its starting point because the pilot was likely unconscious at that point.

The intercepting pilots reported visually seeing the pilot slumped over to the right, confirming he was unconscious or non-responsive at some point in the flight. It is unknown how the three passengers were faring at this point and whether or not they were conscious. McSpadden said that based on known information, two factors likely could have led to the crash, hypoxia or rapid decompression.

Hypoxia occurs when there is not enough oxygen to feed the brain, eventually leading to a state of unconsciousness. The lack of responsiveness from the pilot had people speculating hypoxia early on, similar to a 1999 crash when a Learjet 35A lost cabin pressure and flew aimlessly around the country before crashing in a South Dakota pasture and killing PGA pro golfer Payne Stewart.

[texas booster]

Hypoxia has what is called an insidious onset, meaning the signs and symptoms occur so gradually that they are fully established by the time you become aware of them. When the cabin pressurization system does not work and the pilot is unaware, due to the insidious nature of hypoxia they will also likely be unaware of the signs and symptoms before it is too late. McSpadden said it is possible that the pilot was unaware of a cabin pressurization issue until the hypoxia had taken over and he was impaired or incapacitated. In similar instances, this occurred about 20 minutes into the flight. Based on what is known, there is an indication of an insidious hypoxic event.

The second, slightly more dramatic depressurization event, is rapid decompression. When this occurs around flight level 350, or in that range, a pilot will have roughly 30-60 seconds to put on a mask before they use consciousness. The concept “Time of Useful Consciousness” outlines different altitude levels and the amount of time needed to put a mask on before losing consciousness. Pilots are trained to put the masks on quickly in emergent situations, especially pilots with the type rating and background this pilot had.

[Gay State Conservative]

I saw a bit of that yesterday. The lesson I took from it is *never fly in a plane that has only one pilot and that pilot is a 69 year old guy*.

[riverrunner]

In this case it might very not made a difference.

[Gay State Conservative]

Yah,they said that depressurization might have been the cause. But if,by chance,it was a heart attack or stroke imagine what the passengers were going through. But then,I suppose they might not have known that there was something wrong until the end.

[mikey_hates_everything]

Maybe an auto-pilot where the plane automatically descends to a breathable altitude if the pilot doesn’t respond to a regular stimulus and there’s high altitude (low) pressure within the cabin? Doesn’t seem more dangerous than the plane eventually crashing on its own somewhere due an incapacitated pilot.

[guest7]

"The AOPA released its early analysis..."

This is Total B.S.

"The intercepting pilots reported visually seeing the pilot slumped over to the right,..."

Hypoxia would have caused the windows to "ice over"; hence, the F-16 pilots couldn't have seen anything inside the plane.

[RckyRaCoCo]

...never fly in a plane that has only one pilot and that pilot is a 69 year old guy

...particularly post covid/jab.

[Bartholomew Roberts]

Depressurization would have frosted the windows. Hypoxia is the human loss of oxygen. It could have many causes.

There was a recent General Aviation crash because a supplier of oxygen bottles filled some with pressurized atmospheric air instead of pressurized O2.

The pilot suffered hypoxia, passed out and was subsequently killed.

Another case was a faulty O2 line that leaked. The copilot suffered hypoxia and fell into unconsciousness but the pilot survived and landed.

None of these hypoxia cases frost windows.

[LibertyOh]

Simpler and quicker solution is for pilots to wear an oxygen monitor. I have a Wellue O2 ring that monitors my oxygen level and vibrates when low, increasing in intensity if it doesn’t rise. While asleep it can nudge me to move and breathe better, and has woken me up when I didn’t do enough to improve my breathing (I do use both CPAP and oxygen). If the pilot had been wearing one (wireless, very comfortable) he would have known his oxygen level was dropping and been able to do something in time.

[Ronaldus Magnus]

That was quick! It must be that they don’t want anymore NRA and Trump donors to die. Last time I saw such a fast advisory was immediately after TWA Flight 800 when every 747-100 had to have the wiring redone in their center fuel tank. Good thing neither of these are cover-ups!

[Rappini]

Good point.

[Paal Gulli]

"Yah,they said that depressurization might have been the cause.

More likely failure to pressurize rather than depressurization. Either should have set off an alarm, so neither one is likely without multiple systems failures. But failure to pressurize (along with a defective alarm) is more likely to take the pilot unawares than a rapid depressurization event, alarm or no, because the effects of a rapid depressurization at altitude (ears popping, formation of fog in the a/c, etc) tend to be obvious.

And the first step in the Quick Reaction Handbook (which is the part that the pilot has to commit to memory) in the event of either depressurization (or smoke in the cockpit) is to don the oxygen mask. So if the pilot had even an inkling of a hint of a depressurization, he should have had on his oxygen mask in single-digit seconds.

It's more likely he went to sleep in the climb because the a/c wasn't pressurizing.

Or maybe the pressurization was fine and the pilot the stroked out and none of his passengers noticed anything was wrong until it was too late.

[Paal Gulli]

Those "Time[s] of Useful Consciousness," it bears mentioning, are for rapid depressurization events. The times lengthen considerably if the depressurization is gradual.

Time of consciousness at FL 250 is 3-5 minutes, FL 300 is 1-3 minutes, yet people can and have climbed 29,000-ft Mt Everest without supplemental oxygen. But no-supplemental-O2 efforts require a lengthy acclimatization period at altitude.

[Robe]

No depressurization, intercept pilots were able to see the pilot slumped over, windows would have been frosted over if a decompress, most likely a medical issue.

[Paal Gulli]

"No depressurization, intercept pilots were able to see the pilot slumped over, windows would have been frosted over if a decompress, most likely a medical issue."

Failure to pressurize isn't a depressurization. Humidity vents overboard along with the cabin air in the climb. The pilot -- if he's still breathing -- still would be respiring moisture.

OpSpec SOP of many organizations includes turning on windscreen anti-ice in the run-up in the belief it will make the windscreen more pliable and less likely to shatter in the event of a bird strike. Low humidity and operating windscreen anti-ice would have reduced and could have eliminated the tendency to ice. I think it's speculative to say the icing had to have been so severe that the intercept pilots could not possibly have seen the outline of a shape slumped forward in the left seat.

I'm not arguing it wasn't a medical, I'm arguing that isn't the only option that fits the known details.

[guest7]

You missed the point.

" McSpadden said that based on known information, two factors likely could have led to the crash, hypoxia or rapid decompression."

What caused his "Hypoxia"?

N611VG Was NOT a loss of Pressurization. Part I

N611VG Was NOT a loss of Pressurization. Part II

AOPA; and Richard McSpadden; should check this out also.