Sydney Airport Message Board - Qantas Depressurisation

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Easy, make it a procedure after the aircraft has landed to pull the CB for the CVR then problem solved.

Quote:

Originally Posted by Brenden S (Post 9556)

Crew and Pax systems are totally separate, however they are installed in the same area. I showed the picture of the fwd cargo hold as It was the best I could to. The frames to the left is where the oxy cylinders are.

Thanks, thought so. Just when you said one oxy bottle discharging could allow all the others to discharge as well i was a bit confused. I do uunderstand that without check valves, if one bottle fails, the others in the line will discharge to 'space' as well.

Quote:

Originally Posted by Philip Argy (Post 9557)

I have seen a number of ATSB Reports that note that the CVR was left running after a major incident and therefore wiped out all record of the incident they were investigating, but usually this relates to post landing where I gather the protocol is to turn off the CVR to preserve the previous two hours rather than capture ground staff chatter.

If more than 2 hours elapses between incident and shutdown of the a/c post landing, I don't see how the incident can be preserved with existing CVR processes. It shouldn't be hard these days to increase the capacity of a CVR, or to make provision for CVR history to be copied manually to other onboard storage media after any major incident so that, short of loss of a/c, more than 2 hours of CV is available.

The CVR uses a metalic tape that is reasonably resistant to impact and severe heat damage, which is why its used. For space reasons, 2 hours is regarded as a maximum time required for recording purposes. It is felt that 2 hours is enough to capture the incident and allow the aircraft to either crash or land and still have the data on the CVR. The legal minimum is i believe 30 minutes.

As for transfering the data to another medium, that will incure a cost that most airlines will not wear unless its mandatory. Larger aircraft maybe able to handle the weight penalty and have room, but smaller aircraft may not have the capability. I am unaware of what technology could be used to transfer data from the metalic tape to a data storage device either - i dare say it can be done however.

There was talk many years ago of only having the CVR activated inflight via touch down micros, however some incidents start whilst on the ground so that idea was squashed quickly.

Also, the data storage device would need to be impact and heat resistant, similar to the FDR.

I thought only 30 minutes were recorded and that the tape is long gone with the introduction of chips to record to?

Cockpit Video Recorder?

I'm not sure what is physically in the CVR these days but you'd expect it to be solid state of some kind as long as it can survive the trauma of a crash. But that doesn't mean it isn't still set up only to store a rolling two hour record. What I was suggesting is that instead of overwriting there should be an 'incident switch' which will dump the recording to supplementary media after two hours so that the historical CVR record is preserved.

In this day and age when I can store 60 hours of HD television on a hard drive that fits in the palm of my hand, and I can buy ruggedised noteboks that will survie a lot of trauma, I'd have thought it possible to design somewhat more useful CVR/FDR devices. And how long before the "v" becomes "video" rather than "voice"?

Quote:

Originally Posted by Philip Argy (Post 9569)

Yeah, but don't forget this aircraft is 17 years old. Any new design such as a hard drive which can record 60 hours (or whatever) would have to be integrated with avionics/FMS which are 20+ years old in design.

Perhaps we'll see the kind of stuff you mention on the 787/A350.

from a NTSB web site

Quote:

Specifications

Flight Data Recorder
Time recorded 25 hour continuous
Number of parameters 18 - 1000+
Impact tolerance 3400Gs / 6.5 ms
Fire resistance 1100 degC / 30 min
Water pressure resistance submerged 20,000 ft
Underwater locator beacon 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation

Cockpit Voice Recorder
Time recorded 30 min continuous, 2 hours for solid state digital units
Number of channels 4
Impact tolerance 3400Gs / 6.5 ms
Fire resistance 1100 degC / 30 min
Water pressure resistance submerged 20,000 ft
Underwater locator beacon 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation

So yes, they use solid state devices and yes they probably can build storage devices - if you wish to design, patent and sell you'd make the money. I doubt that your standard storage device can handle that type of trauma.

ATSB Media Release 2008/28

Here is what the ATSB announced at its Media Conference at 2pm this afternoon:

Quote:

Investigation into Boeing 747- 400 depressurisation and diversion to Manila, Philippines

30 July 2008

Introduction

As you are aware the ATSB is leading this safety investigation with the assistance of a number of other organisations and agencies, including the Civil Aviation Authority of the Philippines, the National Transportation Safety Board and the Federal Aviation Administration of the USA, the Civil Aviation Safety Authority of Australia, Qantas and Boeing.
Flight Data Recorder

The data from the flight data recorder has been recovered and downloaded. Initial analysis of the data indicates that the aircraft decent from the decompression event at 29,000 feet to the altitude of 10,000 feet, where no masks are required, took about five and half minutes, with an average descent rate of about 4,000 fpm. The ATSB is still verifying and analysing the data on the recorder.
Door

The ATSB can confirm that it appears that part of an oxygen cylinder and valve entered the passenger cabin and impacted the number 2 right door frame handle, thereby moving the handle part way towards the open position. However, the door handle mechanism has been sheared as it is designed to do if an attempt is made to open the door in flight, so the position of the door handle is not representative of the position of the door lock mechanism or the security of the door. The investigation team have confirmed that the door latches were still engaged. Additionally the door is of the plug-type that first needs to be pulled into the cabin, rotated 90 degrees then pushed out to open. So there was never any danger of the door opening.
Cabin Masks

The investigation team have surveyed the passenger cabin including the oxygen masks. The team found that most of the oxygen masks had deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask. According to the airline, there were 346 passengers on board. Inspection by the ATSB shows that 484 masks had deployed, that is, dropped from the ceiling. Of those, 418 had been activated by pulling on the mask to activate the flow of oxygen. Only a small number of masks appeared to have had the elastic retaining strap adjusted by the passengers. It also appears that a small number of masks did not deploy from the passenger modules. Investigations into this aspect of the accident are continuing.
Interviews are continuing with the cabin crew in relation to this issue. Additionally, the ATSB is preparing a passenger survey that will be sent to all passengers to gather information about their experience of the event. The ATSB also plans to interview those passengers that encountered specific problems either with the masks or the decompression event.
Oxygen System

The investigation team is still examining the oxygen system, including liaising with the manufacturer to determine if the flow of oxygen was adequate for the five and a half minute descent to 10,000 feet, where the masks were no longer required.
ILS

The team have confirmed that the aircrafts three Instrument Landing Systems (ILS) and the anti-skid system were not available for the arrival and landing at Manila. However, evidence to date indicates that all the aircrafts main systems, including engines and hydraulics were functioning normally. The approach to Manila airport was conducted in visual conditions. It should be noted that other pilot navigation instruments (VOR and NDB) were still available to the crew should the conditions not have been visual. Additionally, Air Traffic Control could have provided radar assistance if the crew had required it.
Flight Crew

From the evidence gathered to date it appears that the flight crew have responded to and managed the emergency situation extremely well. It is apparent that they followed the procedures they have trained for in simulators, which ensured the best possible outcome for the aircraft, the passengers and crew.
Notify ATSB

A reminder that the ATSB requests that any passengers that experienced issues during the flight, or those who photographed or videoed the incident, contacts us via email atsbinfo@atsb.gov.au , telephone: 1800 020 616, or facsimile 02 6247 3117.
The investigation will need time to review and analyse the evidence collected to date and to plan and undertake further evidence gathering and analysis. It is difficult to say how long an investigation such as this will take. However, a preliminary factual report will be released by the ATSB within about 30 days and, should the need for urgent safety action by any agency be identified, the ATSB will immediately notify the relevant agencies who are best placed to address the issue. At this point, unless there is any significant development in the investigation, further media conferences are not anticipated and further information will be released as part of the ATSBs preliminary report.

You have to love the main story on news.com.au...

"Qantas landing systems failed"
"Stricken Qantas jet / AFP

INVESTIGATORS say an on-board explosion left a Qantas pilot to land a stricken passenger jet without instrument landing systems."

And of course, right at the end of the article: "The approach to Manila airport was conducted in visual conditions, and it should be noted that the pilot had other navigation instruments available (if visibility had been a problem)."

Dont you just love how they drum up all of this to make it look so much worse than it actually is?

Quote:

Qantas landing systems failed

July 30, 2008 04:26pm

A QANTAS pilot brought a passenger plane into Manila airport without instrument landing systems after the aircraft was damaged by an exploding exygen bottle, investigators say.

Passengers and crew all escaped injury when the Melbourne-bound Boeing 747-400 made an emergency landing in the Philippines after a mid-air explosion tore a hole in its fuselage last Friday.

The Australian Transport Safety Bureau (ATSB) said today a piece of the oxygen tank entered the passenger cabin after smashing through the cabin floor and hit an emergency door handle, moving it part way into the open position.

ATSB spokesman Julian Walsh said passengers were not in danger, because the position of the handle did not mean the security of the door was at risk.

He told reporters the investigation team had confirmed the door latches were still engaged, and the design of the door meant there was never any danger of the door opening.

"The team have confirmed that the aircraft's three instrument landing systems and the anti-skid system were not available for the arrival at Manila," Mr Walsh said.

"However, evidence indicates that all the aircraft's main systems, including engines and hydraulics, were functioning normally.

"The approach to Manila airport was conducted in visual conditions, and it should be noted that the pilot had other navigation instruments available (if visibility had been a problem)."

The ATSB said some passengers' oxygen masks had failed to deploy correctly.

"I don't know the exact number, but we're talking less than 10 as I understand it,'' Mr Walsh said.

"But that's subject to verification and confirmation.''

Some passengers have told of their panic after they were unable to access the oxygen masks as the drama unfolded.

The ATSB said it would interview Qantas cabin crew and passengers who encountered problems with the masks.

Mr Walsh said the investigation team was still examining the oxygen system to determine if the flow was adequate for the five-and-a-half minute descent from 29,000 feet to 10,000 feet, where the masks were no longer required.

It was still unclear as to what caused the oxygen bottle, about the size of a scuba tank, to explode.

The bottle, which was in a bank of bottles that provided oxygen to passengers, pierced the floor near one of the major exit doors, Mr Walsh said.

He said there was a crew seat in the vicinity of where the bottle entered the cabin but that no crew member was in the seat at the time.

"Whether the bottle itself has actually exploded or whether the valve has failed, or whether that has been a secondary event as a result of something else hitting the bottle, it is obviously very important for us to look at.

"But clearly the (oxygen bottle) has travelled vertically through the floor of the aircraft, glanced with the door handle and impacted with the ceiling of the cabin.

"I think it's fair to say that for something to penetrate the floor and to move the handle, that component was travelling at some significant speed.''

Mr Walsh said it appeared that the flight crew had managed the situation "extremely well''.

"Certainly, our review of all the information that's available to us to date shows that the crew responded as you would expect them to do.

"It would appear to us that they've done very close to a text-book response.''

Mr Walsh said the investigation team would now need time to analyse the data that had been collected, adding that a preliminary report should be available within about 30 days.

News.com