DC Sonic Boom/Citation Down in VA
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There are later Citation 560 models (the 560XLS and XLS+) whose autopilot has an automatic emergency descent mode. One prerequisite for that are electronically controllable engines (FADEC) which this 1990 model did not have, unless retrofitted at some later stage.
But there is a much easier and non-technical way by which some of these accidents, including the one over the Baltic Sea referenced above, can be prevented: Employ a second pilot. Money seems to have been no issue here, the aircraft owners could even afford to donate hundreds of thousands of Dollars to politicians. What are a few hunderd Dollars per flight in comparison to that?
But there is a much easier and non-technical way by which some of these accidents, including the one over the Baltic Sea referenced above, can be prevented: Employ a second pilot. Money seems to have been no issue here, the aircraft owners could even afford to donate hundreds of thousands of Dollars to politicians. What are a few hunderd Dollars per flight in comparison to that?
Are there any deficiencies in cabin low pressure warnings that could be addressed to provide better alerting BEFORE the O2 levels fall too low to keep the pilot(s) conscious enough to hear them?
Those same mountains will kill a pilot that has passed out. But maybe if the plane refuses to climb then a pilot with his wits about him will either put on oxygen and push the override or will avoid hitting the mountains, possibly after turning up the pressurization.
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Especially if there is a static sensor problem inhibiting throttles and the pilots are wide awake to see the cumulogranite approaching at 12 o'clock.
Last edited by Feathered; 5th Jun 2023 at 12:57.
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I have no clue what caused this accident at this time, but perhaps it was low cabin pressure / hypoxia. A second pilot may help in some situations or cross checks, but if there is not enough oxygen to keep one pilot conscious, how would a second pilot remain conscious unless there is a mandate that they are more physically fit / able to stay conscious with lower oxygen levels?
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For whatever reason this Zombie aircraft continued to fly the pre-programmed route without communication from Tennessee until reaching it's destination on Long Island where it ran out of FMC waypoints to follow. The autopilot likely dropped into Hdg/HdgHold at that point. The aircraft overflew it's destination (ISP) down runway 24 maintaining FL340 and continued with that heading and level until the final spiral descent in mid-Virginia. My guess is that was at the point it ran out of gas. On passing Washington, had that a/c started a descent towards the Capitol Area it would have been shot down immediately. Instead it maintained FL340 and was allowed to carry on.
It seems very likely the pilot had become incapacitated. Had that incapacitation been confined to the pilot and evident to the passengers either visually or after the expected flight time expired then likely one of them would have attempted to communicate on a radio in some manner. There is no report of any such communication which points to an incapacitation affecting all on board. LIkely a depressurisation. We understand all on board perished and our thoughts are with the family. It may be small relief to the family but it is likely that all on board were peacefully unconscious for some time before the crash took place.
As an ex-military pilot I was obliged to carry out depressurisation training at two-yearly intervals throughout my service. After I moved to the airlines I never understood why that was not mandated for professionally licenced airline pilots.
It seems very likely the pilot had become incapacitated. Had that incapacitation been confined to the pilot and evident to the passengers either visually or after the expected flight time expired then likely one of them would have attempted to communicate on a radio in some manner. There is no report of any such communication which points to an incapacitation affecting all on board. LIkely a depressurisation. We understand all on board perished and our thoughts are with the family. It may be small relief to the family but it is likely that all on board were peacefully unconscious for some time before the crash took place.
As an ex-military pilot I was obliged to carry out depressurisation training at two-yearly intervals throughout my service. After I moved to the airlines I never understood why that was not mandated for professionally licenced airline pilots.
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The various Citation 550 and 560 models that I flew and fly have no audible warning for low cabin pressure. You get a flashing red warning light in the annunciator panel and a flashing red master warning light. Above 14.000 ft (plus minus a few) the passenger oxygen masks will drop automatically which may or may not be seen from the cockpit. There is no door, but some sort of divider and an optional curtain.
But there is a much easier and non-technical way by which some of these accidents, including the one over the Baltic Sea referenced above, can be prevented: Employ a second pilot. Money seems to have been no issue here, the aircraft owners could even afford to donate hundreds of thousands of Dollars to politicians. What are a few hunderd Dollars per flight in comparison to that?
If this was a pilot incapacitation event unrelated to cabin pressure, a 2nd pilot likely would have safely landed the aircraft. However, initial reports seem to support the loss of cabin pressure. ABC News reported a “U.S. official” stated that the pilot was observed passed out. Had the other two adult passengers been conscious (i.e., not a loss of cabin pressure), I would expect the F-16s to have observed some activity onboard the aircraft, especially in the cockpit.
Regarding the comment that the owner could have spent more money on a 2nd pilot, wealthy folks tend to be risk takers. That’s usually how they became wealthy.
Some news reports are stating that the Citation violated or entered DC restricted airspace, triggering the NORAD response. The DC FRZ and SFRA extend upward to but not into Class A airspace. The Citation was in Class A at FL340 during the entire transit of the DC area. Seems likely the NORAD response was triggered as soon as ATC lost radio contact with the Citation, which would have been on the leg to ISP, which tracked well south of DC airspace.
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Where do you stop with mandating stuff that MIGHT have made a difference?
In a 737-300 I once experienced exactly the same circumstances that led to the Helios crash. My ears told me something was wrong as we passed about 4000'. It was quickly fixed but without depressurisation training the pilot gets zero exposure to this situation.
In a 737-300 I once experienced exactly the same circumstances that led to the Helios crash. My ears told me something was wrong as we passed about 4000'. It was quickly fixed but without depressurisation training the pilot gets zero exposure to this situation.
Last edited by Magplug; 5th Jun 2023 at 18:15.
If the cabin pressure gets above 10,000 feet (or some other agreed upon value) that the engines throttle back to a setting appropriate for cruise at that altitude.
I think it would have saved at least 3 aircraft that I know of - all turned into long-range cruise missiles waiting to drop on unsuspecting landscape. Lucked out so far they have missed cities.
There is likely some pressurization warning but it seems not to be reliable or sufficient.
I think it would have saved at least 3 aircraft that I know of - all turned into long-range cruise missiles waiting to drop on unsuspecting landscape. Lucked out so far they have missed cities.
There is likely some pressurization warning but it seems not to be reliable or sufficient.
I see others have responded quicker than me about flaws in this idea, however (terrain).
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Flightaware.com Track
FL340 the whole flight... track log stops abruptly without any evidence of descent.
Reportedly, the flight stopped communicating approximately 14 minutes after departure. The flight log shows that at that point in the flight, it was passing through FL300. So it Is entirely possible that the plane never pressurized and this was not detected by the pilot.. There was a single pilot and three passengers, including a 2 year old child.
https://flightaware.com/live/flight/...700ZZ/0A9/KISP
Reportedly, the flight stopped communicating approximately 14 minutes after departure. The flight log shows that at that point in the flight, it was passing through FL300. So it Is entirely possible that the plane never pressurized and this was not detected by the pilot.. There was a single pilot and three passengers, including a 2 year old child.
https://flightaware.com/live/flight/...700ZZ/0A9/KISP
Last edited by Lake1952; 6th Jun 2023 at 01:36.
I suspect this 25,000 ft exposure would be very different from slow or rapid depressurization at FL340. (My chamber rides were for high altitude glider flying and I have no experience as PIC of pressurized aircraft.)
That would be an interesting option - build a full motion platform hypobaric chamber for check flights with 20 - 30 minute bleed-down from the correct pressure. See how many crews notice. Make sure they are kept busy with a bunch of ATC requests and simulated chatter with the company about a late departure and maybe a re-route for weather.
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Aircraft should come equipped with Garmin emergency Autoland that could safely do an emergency descent while knowing the height of terrain below as well as nearest airport location for the landing. Safest thing especially for single pilot.
A Citation of this vintage does not have quick donning oxygen masks unless retrofitted.
The listed owners have two aircraft, a twin turboprop and the C560.
I’m guessing they had a single pilot flying both aircraft for this family under the less stringent regulations of 14 CFR Part 91.
This was either a medical event or a (de)pressurization issue.
Autopilot went into HDG hold after overflying the last fix in the flightplan followed by the destination.
That would be an interesting option - build a full motion platform hypobaric chamber for check flights with 20 - 30 minute bleed-down from the correct pressure. See how many crews notice. Make sure they are kept busy with a bunch of ATC requests and simulated chatter with the company about a late departure and maybe a re-route for weather.
Of course, none of it is as impressive as an actual chamber with a vacuum accumulator set up for explosive decompression to 35k.
(But there’s not too much that’s insidious about that, especially when it starts snowing in the tank)
Civil airmen can go to CAMI and do not only hypoxic training, but a bunch of other useful things, and it’s all free.
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What I meant to say about the Garmin Autoland capability is obviously not for this Citation, but was aimed at a possible solution for all new single ( or even dual ) pilot jet aircraft. It might need some new programming to support early detection of improper cabin pressure. The goal would obviously be to get the vehicle down to safe altitude ( it has a worldwide terrain database) as soon as possible after detection. then, even if the pilots were temporarily incapacitated, Hopefully all would recover, and if not, the aircraft wouldn’t become an unguided missile