Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

DC Sonic Boom/Citation Down in VA

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

DC Sonic Boom/Citation Down in VA

Old 6th Jun 2023, 11:45
  #41 (permalink)  
 
Join Date: Oct 2019
Location: USA
Posts: 991
Received 364 Likes on 196 Posts
Before advanced autoland, perhaps FDRs and CVRs. could be added to decrease the mystery and investigation costs? If a traditional FDR isn't easily retrofitted, then a system that captures video of the majority of the controls and the entirety of the control panel would be enough? A high-def web cam and a single board computer in a tough box would likely suffice. Apparently all the NTSB has found so far is aluminum confetti.
MechEngr is online now  
Old 6th Jun 2023, 13:29
  #42 (permalink)  
 
Join Date: Jul 2003
Location: An Island Province
Posts: 1,257
Likes: 0
Received 1 Like on 1 Post
Before considering extreme technical fixes for a particular accident, and without knowledge of the cause; question if FAR 23 GA aircraft have warning systems - visual and audio, as required by FAR 25 for commercial aircraft - high cabin alt.
alf5071h is offline  
Old 6th Jun 2023, 14:36
  #43 (permalink)  
 
Join Date: Aug 2000
Location: Near Stuttgart, Germany
Posts: 1,106
Likes: 0
Received 6 Likes on 5 Posts
Originally Posted by alf5071h
Before considering extreme technical fixes for a particular accident, and without knowledge of the cause; question if FAR 23 GA aircraft have warning systems - visual and audio, as required by FAR 25 for commercial aircraft - high cabin alt.
The Cessna C560 is an FAR 25 aircraft. Single pilot operation like in this case requires special FAA certification.
what next is online now  
Old 6th Jun 2023, 15:25
  #44 (permalink)  
 
Join Date: Apr 2014
Location: Behind a cloud
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Magplug
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.
Back in my RAF days and even as an engineer who flew in fast jet back seats (air tests, trips to assess/repair landaways) I was required to regularly attend North Luffenham for hypobaric chamber hypoxia training etc. I was surprised to discover that civvy airline pilots (and cabin crew) do not do likewise.
keri is offline  
Old 6th Jun 2023, 15:28
  #45 (permalink)  
 
Join Date: Mar 2015
Location: Virginia, USA
Posts: 498
Likes: 0
Received 34 Likes on 24 Posts
Originally Posted by MechEngr
Before advanced autoland, perhaps FDRs and CVRs. could be added to decrease the mystery and investigation costs? If a traditional FDR isn't easily retrofitted, then a system that captures video of the majority of the controls and the entirety of the control panel would be enough? A high-def web cam and a single board computer in a tough box would likely suffice. Apparently all the NTSB has found so far is aluminum confetti.
In this specific accident scenario, what useful information would you expect from a CVR and FDR?

With the increased use of digital electronic devices (e.g., mobile phones, tablets/EFB, engine instrument monitors), accident investigators are finding useable data for accident investigation even though these devices are not designed for crash resistance. There’s also increased use of FDM/FOQA devices, some of which provide video (e.g., N13GZ, Appareo 1000).
BFSGrad is offline  
Old 6th Jun 2023, 15:58
  #46 (permalink)  
 
Join Date: Sep 2001
Location: Toronto
Posts: 2,564
Received 42 Likes on 21 Posts
If the cabin altitude is left to climb, you are steadily losing IQ points. I don't know what warnings the 560 shows, but there's a possibility that by the time the warnings come on, the crew may not have sufficient cognition to react properly.

I remember one flight in my glider before I installed oxygen and being perplexed about which hand of the altimeter was what at 12,500.
RatherBeFlying is offline  
Old 6th Jun 2023, 16:05
  #47 (permalink)  
 
Join Date: Jul 2003
Location: An Island Province
Posts: 1,257
Likes: 0
Received 1 Like on 1 Post
what next - FAR 25, thank-you.

Thence if an alerting system was fitted, was it functional, was it adhered to ?

I recall that it was suspected that the Helios 737 audio alert was mistaken for overspeed - warning horn.
alf5071h is offline  
Old 6th Jun 2023, 16:48
  #48 (permalink)  
 
Join Date: Aug 2000
Location: Near Stuttgart, Germany
Posts: 1,106
Likes: 0
Received 6 Likes on 5 Posts
Originally Posted by alf5071h
Thence if an alerting system was fitted, was it functional, was it adhered to ?

I recall that it was suspected that the Helios 737 audio alert was mistaken for overspeed - warning horn.
I am pretty sure that the investigation will thoroughly look into these items. According to internet wisdom, the aircraft was only recently imported from Venezuela in January this year. What equipment was installed and functional should be listed in the maintenance records. The little information that has been disclosed about the pilot is that he was a retired airline captain with over 25.000 flying hours.

As written above, the C560 has no aural cabin pressure warning. Only annunciator lights. When then sun shines directly onto the annunciator panel, a warning light coming on can easily be missed. As a backup warning, the passenger oxygen masks drop automatically when passing 14.000ft, startling the passengers, who will certainly ask the pilot what's going on. But this only works if the relevant switch is in the correct position and the oxygen bottle has enough pressure and the bottle valve is open.
what next is online now  
Old 6th Jun 2023, 19:07
  #49 (permalink)  
 
Join Date: Sep 2022
Location: Perpetually circling LAM for some reason
Posts: 152
Received 9 Likes on 5 Posts
Originally Posted by alf5071h
what next - FAR 25, thank-you.

Thence if an alerting system was fitted, was it functional, was it adhered to ?

I recall that it was suspected that the Helios 737 audio alert was mistaken for overspeed - warning horn.
On the Helios flight it was confusion between the takeoff config horn and the cabin alt warning horn (which were identical as they used the same horn), coupled with the fact that in the 737 Classic a secondary symptom of excessive cabin altitude was the EFIS instruments (EADI and EHSI) going monochrome as the thinner air failed to cool the avionics effectively.

The already hypoxic crew were trouble shooting entirely irrelevant problems; hence why afterwards Boeing installed lights to indicate which warning was going off.

I have not flown the Classic for a long time, it was an absolutely marvellous machine, but it could be very very unforgiving compared to more modern aircraft. That said, hypoxia is one of the biggest threats we face, not least as the condition itself can interfere with your ability to realise you are in difficulty.
Speed_Trim_Fail is offline  
Old 6th Jun 2023, 22:50
  #50 (permalink)  
GBO
 
Join Date: Mar 2008
Location: Australia
Posts: 118
Received 5 Likes on 1 Post
There have been a few hypoxia related accidents which could explain this flight
eg Helios 522, Malaysia MH370, Payne Stewart’s Lear Jet, VH-SKC.

However, there are other pilot incapacitation scenarios
eg pilot suffering from a medical condition
GBO is offline  
Old 6th Jun 2023, 23:14
  #51 (permalink)  
TWT
 
Join Date: Apr 2008
Location: troposphere
Posts: 848
Received 57 Likes on 29 Posts
MH370 was a hypoxia related incident ?

No-one knows what happened to MH370 with any certainty.
TWT is offline  
Old 7th Jun 2023, 01:07
  #52 (permalink)  
 
Join Date: Jul 2013
Location: canada
Posts: 17
Received 0 Likes on 0 Posts
N611VG Was NOT a loss of pressurization By Dan Grader On YouTube


This analysis by Don Gryder seems to make a lot of sense. Basically the pilot had a medical incapacitation ( heart attack, stroke, etc) early in the flight which none of the passengers noticed. On a loss of pressurization incident, the windows will fog over. This plane had clear windows. Basically, there was no copilot to take over when the pilot became incapacitated.

Dan covers all the salient points.
tarkay01 is offline  
Old 7th Jun 2023, 03:03
  #53 (permalink)  
 
Join Date: Aug 2013
Location: Washington.
Age: 74
Posts: 1,106
Received 167 Likes on 62 Posts
Originally Posted by tarkay01
N611VG Was NOT a loss of pressurization By Dan Grader On YouTube

https://youtu.be/s0G9sthn8bU

This analysis by Don Gryder seems to make a lot of sense. Basically the pilot had a medical incapacitation ( heart attack, stroke, etc) early in the flight which none of the passengers noticed. On a loss of pressurization incident, the windows will fog over. This plane had clear windows. Basically, there was no copilot to take over when the pilot became incapacitated.

Dan covers all the salient points.
Perhaps, but I wouldn’t be so hasty. Yes, rapid depressurization will lower the temperature and may fog the windows. But the slower, insidious depressurization would not. Was the 14,000 foot cabin alert working? Or noticed? Was the single pilot already physically compromised when the alert appeared? Too early for rash conclusions.
GlobalNav is offline  
Old 7th Jun 2023, 03:17
  #54 (permalink)  
 
Join Date: Nov 2011
Location: Japan
Posts: 2,067
Received 178 Likes on 111 Posts
Did we know if the Andrews F-16 pilot(s) saw the passengers?
jolihokistix is offline  
Old 7th Jun 2023, 04:40
  #55 (permalink)  
 
Join Date: Oct 2019
Location: USA
Posts: 991
Received 364 Likes on 196 Posts
Gryder mentions the Payne Stewart plane was reported to have frosted windows - covered here: https://en.wikipedia.org/wiki/1999_S...t_interception

On the other hand, the windows on the Helios flight were all clear enough to see the cockpit with slumped pilot and then the entry by the flight attendant on oxygen bottle and the dangling oxygen masks in the passenger area.

Both aircraft had previously reported for problems with pressurization.

I'm not sure the passengers in the instance of a medical problem would fail to notice the additional time, nearly an hour, in the air no matter how distracted. All falling asleep is possible, but it's not that long a flight.

The current report is that ATC failed to establish contact about 15 minutes after takeoff, about the time for hypoxia to set in but, sure, stroke or heart attack could happen any time.
MechEngr is online now  
Old 7th Jun 2023, 04:44
  #56 (permalink)  
 
Join Date: May 2011
Location: Surrey UK
Age: 75
Posts: 236
Received 7 Likes on 6 Posts
Originally Posted by alf5071h
I recall that it was suspected that the Helios 737 audio alert was mistaken for overspeed - warning horn.
I think most Mach over-speed warnings are a clacker sound (similar to a football supporters rattle clacker) not a horn.
Remembering the BAC1-11 400 very easily flew on the clacker.
aeromech3 is offline  
Old 7th Jun 2023, 07:46
  #57 (permalink)  
 
Join Date: Feb 2003
Location: Blue sky
Posts: 306
Received 23 Likes on 15 Posts
Originally Posted by MechEngr
On more modern aircraft are there design/regulatory mandates to override the throttles when the cabin pressure goes over 10,000 feet? It seems obvious enough. How many crashes would have been avoided by such a mechanism?
I would think you would create many extra hazards as well? Linking a throttle override to cabin pressure seems a very dangerous/confusing thing to do. Think about other traffic, terrain clearance,... It might also creates other problems in regard to scheduled unpressurized flights due to (ie) technical problems known in advance with the pressurization system. There are more simple solutions.

TUC at 10000ft is not the same as a depressurization at +30000ft. There is plenty of time to react, so as long as you have a good system informing the pilots correctly, there should be no issue.

Last edited by BraceBrace; 7th Jun 2023 at 09:31.
BraceBrace is offline  
Old 7th Jun 2023, 11:42
  #58 (permalink)  
 
Join Date: Aug 2005
Location: EDLB
Posts: 370
Received 10 Likes on 6 Posts
I would not rule out a pressurization problem that quick.Even so the passengers have no formal training, you would expect that on a GA single pilot operation they will get an idea if the sole pilot is incapacitated and some flares are shot by an F16 while they gaze into your windows.
There is no door between row 0 and the passenger area.
EDLB is online now  
Old 7th Jun 2023, 13:28
  #59 (permalink)  
 
Join Date: Dec 2018
Location: Florida
Posts: 259
Received 10 Likes on 3 Posts
Question I do not know the answer to...is the the "frosted windows" effect more likely to happen when a decompression occurs at altitude vs. a situation where the plane essentially never pressurizes as it climbs to altitude?
Lake1952 is offline  
Old 7th Jun 2023, 15:06
  #60 (permalink)  
 
Join Date: Mar 2015
Location: Virginia, USA
Posts: 498
Likes: 0
Received 34 Likes on 24 Posts
DG’s thesis rests on two key points: (1) the momentary pause at FL230 (about 9 min into the flight) shows that the pilot was alive and well at that point with a properly functioning pressurization system, and (2) the passengers in the back were oblivious to the pilot status for the entire duration of the longer-than-planned flight.

Unfortunately (but typically) he combines a plausible analysis with clumsy drama at 4:08, unnecessarily emphasizing with great certainty that the passengers were conscious and died a horrible death. There was a statement attributed to Churchill where he described John Foster Dulles when U.S. Secretary of State as a bull that brings along his own china shop. An apt description for DG.

Regarding the first point it also seems possible that, given the rapid rate of climb along with the TUC at that altitude, that the pilot would still able to operate aircraft controls and respond to ATC while experiencing the onset of hypoxia. Curious to know if the pause at FL230 was ATC directed.

As to the second point, I find it unlikely that both mother and nanny would sleep, leaving a 2-year-old unsupervised. As to the 2-year-old sleeping, my experience is that, when cooped up in an airplane cabin, sleeping is not among the top 3 potential activities for a 2-year-old. I also find it unlikely that, if awake, the passengers were so engrossed in some unspecified activity, that a slumped-over pilot or extended flight time would go unnoticed until the final spiral to the ground.
BFSGrad is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.