Airbus A320 crashed in Southern France
If you are referring to OEB48: Rather unlikely.
For multiple reasons.
Besides what @Lonewolf mentioned:
1. They were in cruise. Freezing would have occcured earlier in all likelyhood.
2. This problem is mostly relevant in climb. In climb Mach number will increase with altitude, thus critical AoA will reduce. At the same time the AoA will increase with decreasing CAS. Therefore with a probe frozen at a constant angle the system will try to correct for increasing Mach. In cruise Mach won't change significantly and Alpha_prot won't usually be reached (especially since there was no significant weather reportde in the area). Only at Alpha_prot and at the same time significantly increasing Mach number the chain described in the Bulletin will be triggered.
Edit: So in summary for this to apply here you need: No freezing in climb, then freezing in cruise, flying at Alpha_Prot, Mach number increasing. And all at the same time and while flying at ~280kts (Alpha_prot @1g should kick in around 170 - 180 kts, so you would have a margin of about 2,4g).
/Edit
3. They had 8 minutes time to:
pull two CB's or
change heading towards lower terrain or
communicate their problems or
select 7700.
Nothing of those happened.
Not saying it is necessarily decompression but Occam's razor has a hard time with the scenario described in the OEB.
For multiple reasons.
Besides what @Lonewolf mentioned:
1. They were in cruise. Freezing would have occcured earlier in all likelyhood.
2. This problem is mostly relevant in climb. In climb Mach number will increase with altitude, thus critical AoA will reduce. At the same time the AoA will increase with decreasing CAS. Therefore with a probe frozen at a constant angle the system will try to correct for increasing Mach. In cruise Mach won't change significantly and Alpha_prot won't usually be reached (especially since there was no significant weather reportde in the area). Only at Alpha_prot and at the same time significantly increasing Mach number the chain described in the Bulletin will be triggered.
Edit: So in summary for this to apply here you need: No freezing in climb, then freezing in cruise, flying at Alpha_Prot, Mach number increasing. And all at the same time and while flying at ~280kts (Alpha_prot @1g should kick in around 170 - 180 kts, so you would have a margin of about 2,4g).
/Edit
3. They had 8 minutes time to:
pull two CB's or
change heading towards lower terrain or
communicate their problems or
select 7700.
Nothing of those happened.
Not saying it is necessarily decompression but Occam's razor has a hard time with the scenario described in the OEB.
Last edited by henra; 25th Mar 2015 at 15:49.
The 2008 Qantas event is informative. When cruising at 29 000' (cabin altitude 3 700') an oxygen bottle exploded creating a 3 square metre hole in the fuselage. One second later the A/P disconnected and the aircraft pitched nose UP. Three seconds later the cabin altitude reached 10 000'. Pilots put on oxy masks and established communications with each other. At 22 seconds descent was initiated (thrust to idle/ speed brakes extended). At approx 40 seconds the uncommanded climb was reversed and and the descent established, maximum cabin of 25 900' occurred at about this time. The mean rate of descent was about 3 000 fpm and the cabin altitude was about about 3000' below the aircraft's altitude during the descent.
The key points are that at 29 000' and with a 3 sq m hole, cabin altitude reached 10 000' within 3" and 26 000' within 40". With idle thrust, speed brakes extended snd IAS at the cruise IAS, descent rate was ~ 3 000 fpm.
The key points are that at 29 000' and with a 3 sq m hole, cabin altitude reached 10 000' within 3" and 26 000' within 40". With idle thrust, speed brakes extended snd IAS at the cruise IAS, descent rate was ~ 3 000 fpm.
Join Date: Aug 2008
Location: Germany
Age: 67
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
The toxicity of oxygen is a problem when (mostly ill) lungs are exposed to high concentrations of oxygen> 50% for a long time (days). Oxygen radicals are supposed to do structural damage to the alveolar membranes. Another problem of breathing of 100 % oxygen are atelectasis (collapsed areas of the lung due to complete resorption of oxygen in absence of nitrogen). A continous flow, providing an positive endspiratory pressure, solves the problem.Conclusion: If an pilot is alone in the cockpit in dangerous hights, he would be wise to wear a mask, breathing 40 % of oxygen, thus changing his hypoxia tolerance from seconds to minutes. Hygenical problems shouldn`t be a problem in the times of single use devices. By the way- every fire brigade can show you how to keep reusable masks hygienically clean.
Join Date: Apr 2014
Location: Washstate
Age: 79
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
re O2 effects
Tigger said
I've been at 14K feet on Mount Rainier. The above description is accurate, especially when happening almost instantaneously. While climbing from 10,000 feet for 6 to 8 hours allows one to sort of acclimate- most first timers( like myself years ago ) start to have a hard time doing all but the most simple tasks-or concentrating. While one would think you would be gasping for breath above 12K or so, you do NOT notice that effect other than the exertion issue which **seems** to be moderate. IMHO- those who think they can remember a multi step procedure under more severe cases ( above 25 to 30 K feet for example ) are simply kidding themselves. Any such response will probably be from " memory' - muscle memory- or similar. Which requires practice, practice, practice. I'm sure a condensation ( moisture smoke) filled cockpit does not help ..
Between 10,000 and 15,000 ft the ability to perform skilled tasks such as aircraft control and navigation are impaired
Agreed. Over the ocean auto descent after pressurisation failure might be useful but in busy European & US skies a plummet without some sort of ATC clearance could lead to more serious consequences. A mid-air would clearly be more hazardous than temporary hypoxia for some passengers.
Yes, a midair will ruin your day, no argument there. But if you turn off course, it's so freakishly unlikely that it's hardly worth considering. Can anyone reference a single midair resulting from an airline pilot doing what he felt was necessary during a serious emergency?
In an airliner suffering decompression, if you do everything correctly, the pilots are still in serious danger as long as they are at an altitude above which they can operate without supplemental oxygen. If it were me, I'd be on my way to a lower altitude immediately.
Waiting for ATC clearance during ANY very serious emergency was NOT in my bag of tricks back when I was flying over the North Atlantic and Europe. I suspect more people have died by turning control of their aircraft over to ATC than have died by doing what was necessary during a genuine emergency and then telling ATC about it later.
Join Date: Jun 2013
Location: surrey
Posts: 9
Likes: 0
Received 0 Likes
on
0 Posts
NYT
Speaking on the French radio station RTL, Interior Minister Bernard Cazeneuve said on Wednesday that terrorism was “not a privileged hypothesis at the moment,” but that no theories had been definitively excluded. Mr. Cazeneuve said the size of the area over which debris was scattered suggested that the aircraft had not exploded in the air but rather had disintegrated on impact.
He said that the plane’s cockpit voice recorder, the first black box that was recovered, was damaged, but that investigators expected to be able to recover the conversations stored on its memory chip.
But as of early afternoon, a senior official involved in the investigation said analysts had so far been unsuccessful in retrieving any information from the cockpit voice recorder.
Speaking on the French radio station RTL, Interior Minister Bernard Cazeneuve said on Wednesday that terrorism was “not a privileged hypothesis at the moment,” but that no theories had been definitively excluded. Mr. Cazeneuve said the size of the area over which debris was scattered suggested that the aircraft had not exploded in the air but rather had disintegrated on impact.
He said that the plane’s cockpit voice recorder, the first black box that was recovered, was damaged, but that investigators expected to be able to recover the conversations stored on its memory chip.
But as of early afternoon, a senior official involved in the investigation said analysts had so far been unsuccessful in retrieving any information from the cockpit voice recorder.
Join Date: Oct 2013
Location: Sweden
Age: 47
Posts: 443
Likes: 0
Received 0 Likes
on
0 Posts
After looking on a few photos of the crash site, I believe there were some kind of post impact fire. The hillsides are blackened and in one picture you can see a small spruce all black. It seems the soil layer was very thin and it is unlikely that the aircraft would have made a large crater. A dent would be more in line with what the photos tell.
My sympathies goes out for all that lost dear ones and for the rescue crew. I can't imagine the awful awful task they have, picking pieces of humans from the ground. If anybody knows how to help the helpers, I wouldn't think twice to volunteer!
My sympathies goes out for all that lost dear ones and for the rescue crew. I can't imagine the awful awful task they have, picking pieces of humans from the ground. If anybody knows how to help the helpers, I wouldn't think twice to volunteer!
Join Date: Apr 2012
Location: planet earth
Age: 59
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Live speech from Hollande, Merkel and Rajoy.
https://www.youtube.com/watch?v=1ZYZG8Yybgw
https://www.youtube.com/watch?v=1ZYZG8Yybgw
Join Date: Oct 2013
Location: Sweden
Age: 47
Posts: 443
Likes: 0
Received 0 Likes
on
0 Posts
Here is a good picture of the charred mountainside. If you look closely you can see burnt trees. The unharmed terrain is beige-brown with the affected parts being black.
Picture taken from https://www.flickr.com/photos/minist...7649223170784/
Picture taken from https://www.flickr.com/photos/minist...7649223170784/
Join Date: Aug 2010
Location: UK
Posts: 7
Likes: 0
Received 0 Likes
on
0 Posts
I was an ATC instructor, with tuition including ATC handling of all types of aircraft emergencies. In the event of explosive decompression we'd expect the pilot to turn off track, initiate a descent and only then..set the emergency sqk and communicate. With TCAS, turning off track may not be immediately necessary!
Join Date: Mar 2015
Location: Germany
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Food for thought, the "bulkhead" separating the cockpit from the rest of the cabin is obviously not designed as part of the pressure cell. If the door has been beefed up sufficiently to prevent an aggressor entering the cockpit and should it remain (or try to remain) in place during a rapid decompression via the cockpit area then the parts that will not remain in place will be the toilet and galley backwalls. Seeing that the O˛ masks are situated slightly to the rear of the crew and are accessable via a small cover door that has to be raised in order to gain access which could be prevented by debris from the backwall failure. If the main cabin evacuates via the cockpit there will be massive movement in this area. Lets hope the CVR and FDR throw some light on this tragedy
Join Date: Feb 2014
Location: scotland
Posts: 18
Likes: 0
Received 0 Likes
on
0 Posts
BEA press conference lastest
From the Guardian - Recordings successfully extracted from cockpit voice recorders
As the press conference ends, Reuters reports that the French air accident investigator, BEA, says it has successfully extracted recordings from the cockpit voice recorder of the downed Germanwings Jet, contradicting the New York Times report from earlier.
And for elkinsoto - At the briefing, the Hollande said that the “envelope of the second black box has been found, unfortunately not the black box itself”. He said the search goes on for that.
The BEA press conference is about to start.
As the press conference ends, Reuters reports that the French air accident investigator, BEA, says it has successfully extracted recordings from the cockpit voice recorder of the downed Germanwings Jet, contradicting the New York Times report from earlier.
And for elkinsoto - At the briefing, the Hollande said that the “envelope of the second black box has been found, unfortunately not the black box itself”. He said the search goes on for that.
The BEA press conference is about to start.
Join Date: Sep 2001
Location: Alfold, Surrey
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
French media reports fdr housing found but not actual fdr
The Les Echos live app won't let me copy and paste but is reporting that the envelope of the FDR has been recovered but not the actual FDR.
Also that the CVR has been exploited.
Also that the CVR has been exploited.
Join Date: Aug 2008
Location: Ithaca, NY
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by dicks-airbus
From avherald
So looks like Helios 2.
According to Finnish CAA in Finnish newpaper Helsingin Sanomat, the CVR has revealed crew was unconscious in the start of descent.