ATSB Final Report: July 2008 Qantas Boeing 747 depressurization accident

by B. N. Sullivan

The Australian Transport Safety Bureau (ATSB) has issued a final report on the sudden decompression in flight of a Qantas Boeing 747-400 on July 25, 2008.  The accident happened during the cruise phase of Qantas Flight QF30, which was en route from Hong Kong to Melbourne.  The flight diverted to Ninoy Aquino International Airport, Manila where it landed safely.  There were no serious serious injuries to those on board, however the aircraft's fuselage ruptured over an area measuring approximately 2 x 1.5 m (6.6 x 4.9 ft).

The ATSB investigation determined that the fuselage rupture "had been induced by the forceful bursting of one of a bank of seven oxygen cylinders located along the right side of the cargo hold," i.e.one of the oxygen cylinders that provide the emergency supplementary oxygen supply for passengers.

An analysis of the damage produced by the ruptured cylinder showed that the force of the failure had projected the cylinder vertically upward into the aircraft's cabin, where it had impacted the R2 door frame, handle and the overhead panelling and structure, before presumably falling to the cabin floor and being swept out of the aircraft during the depressurisation. No part of the cylinder body was located within the aircraft, despite a thorough search.

The ATSB investigation "was unable to identify any particular factor or factors that could, with any degree of probability, be associated with the cylinder failure event."

Despite the inconclusive outcome of the investigation as to contributing factors, the associated engineering study did confirm that the cylinder type was fit-for-purpose.  There was no individual or broad characteristic of the cylinders that was felt to be a threat to the safety or airworthiness of the design.  Similarly, there was no aspect of the batch of cylinders produced with the failed item, which deviated from the type specification, or provided any indication of the increased potential for the existence of an injurious flaw or defect within that particular production lot.

In other words, in the opinion of the ATSB investigators, the rupture of the oxygen cylinder on Qantas Flight 30 was "a unique event and highly unlikely to happen again."

Here is the link to the full report: ATSB: Oxygen cylinder failure and depressurisation - 475 km north-west of Manila, Philippines, 25 July 2008, Boeing 747-438, VH-OJK

The report includes a number of photos showing the extent of the damage to the aircraft.


RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

Australian Transport Safety Bureau issues interim reports on two Qantas accidents

by B. N. Sullivan

During the past week, the Australian Transport Safety Bureau (ATSB) released interim updates on the investigations of two separate accidents involving aircraft operated by Qantas.

QF 30 depressurization, January 25, 2008

The ATSB issued an interim factual report on the investigation into the depressurization of a Qantas Boeing 747-400 aircraft, registration VH-OJK, on July 25, 2008. That aircraft, operating as Qantas Flight QF30, was en-route from Hong Kong to Melbourne; it diverted to Manila where it made a safe emergency landing. Once on the ground, a large hole in the fuselage was discovered. The ATSB concluded that the failure of an oxygen cylinder damaged the pressure hull and led the depressurization.

The newest report focused on a series of tests carried out on several oxygen cylinders from the same manufacturing lot as the failed cylinder, intended to replicate the failure. The ATSB reports that the "various tests have not been able to replicate the cylinder failure that initiated the accident." The ATSB says:

To date, all pressure tests of the cylinders met or exceeded the relevant safety specifications, with recorded rupture pressures being over twice the maximum working pressure of the cylinders.

The investigation continues, and a final report is expected in early 2010.

Link: Depressurisation – 475 km north-west of Manila, Philippines – 25 July 2008 - Interim Factual No. 2 - 8-page 'PDF' file 

RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

QF 72 in-flight upset, October 7, 2008

The ATSB also issued a second interim factual report on its investigation into an in-flight upset involving a Qantas Airbus A330-303, registration VH-QPA, on October 7, 2008. The aircraft, operating as Qantas Flight QF 72, was en route from Singapore to Perth when it experienced two uncommanded pitch-down events. The flight diverted to Learmonth, Western Australia, where it landed safely.

The new report describes tests carried out in an attempt to discover what caused anomalous behavior of the aircraft's No. 1 Air Data Inertial Reference Unit (ADIRU), which led to the upset. The tests were inconclusive. The ATSB says:

Despite extensive testing and analysis, the reason why the ADIRU started providing erroneous data (spikes) during the 7 October 2008 flight (or the 27 December 2008 flight) has not been identified to date. Nevertheless, the crew operational procedures that were provided by Airbus in October 2008 (and modified in December 2008 and January 2009) significantly reduced the chance of another in-flight upset by limiting the time that a faulty ADIRU could output angle of attack spikes. Airbus is also modifying the FCPC software used in the A330/A340 fleets to prevent angle of attack spikes leading to an in-flight upset.

The ATSB expects to release a final report into this accident in the second quarter of 2010.

Link: In-flight upset 154 km west of Learmonth, WA, 7 October 2008 - 10-page 'PDF' file

RELATED: Click here to view all posts about Qantas Flt 72 on Aircrew Buzz. 

Interim report on the July 2008 Qantas B-747 depressurization accident

The Australian Transport Safety Bureau (ATSB) has just released an Interim Factual Report regarding the sudden decompression in flight of a Qantas Boeing 747-400 on July 25, 2008. The accident happened during the cruise phase of Qantas Flight QF30, which was en route from Hong Kong to Melbourne. The flight diverted to Ninoy Aquino International Airport, Manila where it landed safely, with no serious injuries to the 365 people on board.

After the aircraft landed, a large rupture in the fuselage was discovered.  The ATSB's preliminary factual report about the accident, issued in August of 2008,  stated that one of the cylinders that supplied emergency oxygen to the passenger cabin had "sustained a failure that allowed a sudden and complete release of the pressurised contents," and that "damage to the aircraft's fuselage was consistent with being produced by the energy associated with that release of pressure" from the oxygen cylinder.

Today's interim report elaborated on damage to the aircraft and its systems, with many photos to illustrate. The report also provided detailed descriptions of the engineering tests carried out (and still underway) on components of the accident aircraft's emergency oxygen system, and on similar oxygen cylinders and fittings.

Among the points included in this lengthy interim report:

• there was no evidence of an external explosive event or the use of explosive materials around the rupture area
• no significant maintenance difficulties had been experienced with the passenger oxygen system prior to the accident
• no anomalies in samples of the oxygen gas used to fill the cylinders were identified that would have contributed to this event

Regarding survivability issues, the ATSB said in a media release accompanying the report:

The investigation has determined that, despite the damage to the aircraft's passenger oxygen system caused by the oxygen cylinder failure, the system would have continued to operate for approximately 65 minutes following the depressurisation event. Passenger oxygen was only required for about 5 ½ minutes during the period between the depressurisation event and when the aircraft reached an altitude of 10,000 ft.

The ATSB expects to issue a final report on this accident investigation by the end of 2009.

Here is the link to the report: ATSB Transport Safety Report: Aviation Occurrence Investigation AO-2008-053, Interim Factual - 62-page 'pdf' file

[Photo Source]

Related:

• Qantas Flight QF30 -- Sudden decompression in flight - AircrewBuzz.com, July 25, 2008
• ATSB update on Qantas Flight QF30 accident investigation - AircrewBuzz.com, July 28, 2008
• More information released about the Qantas B747 decompression incident - AircrewBuzz.com, July 30, 2008
• Preliminary factual report issued for Qantas Boeing 747 decompression incident - AircrewBuzz.com, Aug. 29, 2008

...or click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

Preliminary factual report issued for Qantas Boeing 747 depressurization incident

The Australian Transport Safety Bureau (ATSB) has issued a preliminary factual report regarding the in-flight decompression of a Qantas Boeing 747-400 last month. Readers will recall that on July 25, 2008, Qantas Flight QF30 experienced a rapid decompression while en route from Hong Kong to Melbourne. The aircraft (registration number VH-OJK) diverted to Manila, where it made a safe emergency landing. Once on the ground, a large hole in the fuselage was discovered. No one among the passengers and crew on board the flight were injured.

The preliminary factual report issued today by the ATSB reviews the course of events on Flight QF30 and confirms that "the fuselage rupture was aligned with the nominal position of the number-4 passenger emergency oxygen cylinder" in the aircraft's forward cargo hold, and that the oxygen cylinder - one of seven in the bank of cylinders that provided emergency oxygen to the passenger cabin - was missing.

Today's report made clear that one oxygen cylinder had ruptured, and was believed to have caused the breach in the aircraft's pressure hull. How or why the cylinder ruptured has not yet been determined.

The ATSB media release accompanying the report says:

On the basis of the physical damage to the aircraft's forward cargo hold and cabin, it was evident that the number-4 passenger oxygen cylinder sustained a failure that allowed a sudden and complete release of the pressurised contents. The rupture and damage to the aircraft's fuselage was consistent with being produced by the energy associated with that release of pressure. Furthermore, it was evident that as a result of the cylinder failure, the vessel was propelled upward, through the cabin floor and into the cabin space. Damage and impact witness marks found on the structure and fittings around the R2 cabin door showed the trajectory of the cylinder after the failure.

The report includes a number of graphics that illustrate the likely trajectory of the cylinder, based on the observed damage (links below).

The ATSB media release goes on to say:

The investigation to date has also identified other damage to the aircraft, including severing and damage to numerous electrical cables and cable bundles, routed through the lower aircraft fuselage near the point of rupture. In addition, both right side (first officer's) aileron control cables, routed along the right side of the fuselage above the passenger oxygen cylinders, were fractured during the rupture event. However, the aircraft control systems have a redundancy arrangement whereby the first officer's aileron control cables are duplicated by the captain's system, the cables from which were routed along the opposite (left) side of the forward cargo hold. Interlinks between the aileron systems provided the necessary redundancy in this instance, ensuring the continued safety of flight after the event.

Another aspect of the investigation entails cabin safety issues, especially the status of the passenger oxygen masks and equipment. The investigation found that 476 passenger oxygen masks had deployed, and 426 of those had been activated. (Days after the incident, the ATSB had reported that "In all, 484 masks had deployed. Of those, 418 had been activated by pulling on the mask to activate the flow of oxygen.") Of note, the report says that forward crew rest and customer support manager station masks had not deployed.

The investigation is ongoing. Still underway are an engineering investigation into the apparent oxygen cylinder failure; examination of cockpit voice recorder, flight data recorder and quick access recorder information; and a survey of all passengers on the flight.

Links to information released today by the ATSB:

• Depressurisation, 475 km north-west of Manila, Philippines, 25 July 2008, Boeing Company 747-438, VH-OJK - Media Release 2008/33, Aug. 29, 2008
• ATSB Transport Safety Report: Aviation Occurrence Investigation AO-2008-053, Preliminary - Aug. 29, 2008 (38-page 'pdf' file)
• Slides used in the media conference - Aug. 29, 2008 (11-page 'pdf' file)
• Audio of the ATSB Media Conference - Aug. 29, 2008 (28MB)

Previous articles on Aircrew Buzz about this incident and the investigation:

• Qantas Flight QF30 -- Sudden decompression in flight - July 25, 2008
• ATSB update on Qantas Flight QF30 accident investigation - July 28, 2008
• More information released about the Qantas B747 decompression incident - July 30, 2008

RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

More information released about the Qantas B747 decompression incident

The Australian Transport Safety Bureau (ATSB) has released new information regarding their investigation into the recent Qantas Boeing 747-400 depressurization accident. Readers will recall that the aircraft, operating as Qantas Flight QF30, experienced a rapid depressurization at 29,000 feet while en route from Hong Kong to Melbourne on July 25, 2008. The aircraft diverted to Manila where it made a safe emergency landing. No injuries were reported, however the aircraft was found to have a large hole in its fuselage.

First the good news. Today's ATSB news release stated that, "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."

Earlier this week the ATSB reported on the initial inspection of the damaged aircraft, noting (among other things) that one oxygen cylinder, which had been located near the site of the hull breach, was missing. Today the ATSB confirmed that pieces of the missing oxygen cylinder were found in the passenger cabin.

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.

Thus, there seems to be little doubt that the oxygen cylinder exploded inside the cargo bay. The question is, how and why did that happen? And did the exploding oxygen cylinder cause the hull breach and subsequent depressurization, or was it incidental to another causal event?

Here is a rundown of other important points made public today by the ATSB:

• Descent rate - Initial analysis of data from the Flight Data Recorder showed that that immediately following the decompression event at 29,000 feet, the aircraft descended to an altitude of 10,000 feet. The emergency descent took about five and a half minutes, with an average descent rate of about 4,000 fpm.
• ILS - The ATSB confirmed that the aircraft's 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 of the aircraft's main systems, including engines and hydraulics were functioning normally
• Cabin 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. In all, 484 masks had deployed. 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.

Also relevant to the oxygen issue, the ATSB says they are in the process of establishing whether or not "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." Some news reports had mentioned some passenger complaints about malfunctioning masks or sub-optimal oxygen flow.

The ATSB expects to issue a preliminary factual report about this accident within the next 30 days.

RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

ATSB update on Qantas Flight QF30 accident investigation

As often happens following a widely publicized aircraft accident or safety incident involving a major international carrier, there are a lot of rumors and speculation surrounding the July 25, 2008 depressurization in flight of Qantas Flight QF30. With this in mind, I thought it would be useful to post some official (though preliminary) information released today by the Australian Transport Safety Bureau (ATSB), the agency leading the investigation regarding this event.

Here is the text of today's ATSB Media Release:

The ATSB was advised on Friday 25 July of a serious occurrence involving a Qantas aircraft.

The aircraft, a Boeing 747-400 was operating a scheduled passenger service from Hong Kong to Melbourne Australia. At approximately 29,000 feet, the crew were forced to conduct an emergency descent after a section of the fuselage separated and resulted in a rapid decompression of the cabin. The crew descended the aircraft to 10,000 feet in accordance with established procedures and diverted the aircraft to Manila where a safe landing was carried out. The aircraft taxied to the terminal unassisted, where the passengers and crew disembarked. There were no reported injuries.

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 and Qantas and Boeing.

The ongoing investigation has confirmed that there is one unaccounted for oxygen cylinder from the bank of cylinders that are located in the area of the breech. There are 13 oxygen cylinders in the bank that are responsible for supplying oxygen to the passenger masks and cabin crew.

Also recovered are a number of parts of components including part of a valve in the vicinity of the breech. However, it is yet to be determined whether these components are part of the aircraft system.

A number of passengers have reported that some of the oxygen masks appeared not to function correctly when they deployed from the overhead modules. The ATSB intends to examine the oxygen system including the oxygen masks.

The ATSB is also intending to interview the aircraft crew including the cabin crew and make contact with all passengers on the flight. All passengers will be surveyed, while those that had reported problems with mask deployment will be interviewed.

The passenger survey should be available in about two weeks.

The ATSB would like to request that any passengers that experienced issues during the flight, or those who photographed or videoed the incident contacts us via email at atsbinfo@atsb.gov.au.

The ATSB would also like to encourage passengers to write down their recollection of events that occurred. This will aid them with the completion of the passenger survey.

The aircraft flight data recorder and the cockpit voice recorder have arrived in Australia. The ATSB will download the recorders at its Canberra facilities over the next few days.

The ATSB will also be examining maintenance records for the aircraft. This will include any airworthiness directives or alert bulletins that may have been issued by the regulators or the manufacturers.

Additional factual information about Qantas Flight QF30 and the investigation into the cause of the accident will be posted here on Aircrew Buzz as it becomes available.

UPDATE July 29, 2008: Today the ATSB released another statement, indicating that the accident aircraft had been moved to a hangar, and that the "remainder of the freight on the aircraft has been progressively examined and removed from around the area of the rupture."

The team has removed the outer panels around the ruptured area and they are examining the interior of the cabin including the onboard oxygen system, the passenger masks and portable crew oxygen cylinders.

The aircraft's flight data recorder (FDR) and cockpit voice recorder (CVR) have been removed and sent to Canberra for analysis. The two hour CVR recording was found to commence after the descent and diversion into Manila. The FDR, which nominally records 25 hours of data, is being downloaded at the ATSB facilities. Interviews with both flight crew and cabin crew are being conducted today in Melbourne.

RELATED: Click here to view all posts about Qantas Flt 30 on Aircrew Buzz.

Qantas Flight QF30 -- Sudden decompression in flight

A Qantas Boeing 747-400 made an emergency landing at Manila today, July 25, 2008, after experiencing a sudden decompression in flight. Qantas Flight QF30 had been en route from Hong Kong to Melbourne. A Qantas press release about the incident said that "all 346 passengers and 19 crew disembarked normally and there were no reports of any injuries to passengers or crew."

The aircraft was said to be at an altitude of about 29,000 ft when the crew reportedly heard a loud bang, followed by a rapid depressurization of the cabin. Oxygen masks deployed in the passenger cabin, and various news reports quoted passengers who said a "wind" passed through the cabin carrying with it loose papers and bits of debris. The crew immediately executed an emergency descent to 10,000 ft and diverted to Manila where the aircraft landed safely at about 11:15 AM local time.

Upon landing, a large hole in the fuselage was discovered, just forward of the starboard wing. The U.S. National Transportation Safety Board (NTSB), which is sending a team to assist with the accident investigation, said in an advisory that the aircraft has a 5 foot hole in the cargo area forward of the right wing leading edge and there is also some wing damage.

News photos taken of the aircraft after it was parked on the ramp at Manila, such as this one from Reuters, show that a panel of the fairing between the wing and the body had separated, revealing substantial structural damage inside. A piece of the aircraft's pressure hull is missing, as well as sections of the fuselage frame. What appears to be baggage or cargo is visible through the gaping hole. In all, not a very pretty sight!

The accident investigation team will include representatives of the Australian Transportation Safety Bureau (ATSB); Qantas Airways; the U.S. NTSB and Federal Aviation Administration (FAA); Boeing; and possibly others.

In a second Qantas press release, the airline's CEO, Geoff Dixon, praised the pilots and cabin crew for the way they handled the incident. I would like to join in extending congratulations to the entire crew of Flight QF30 for a job well done.

[Photo Source]

Related:

• ATSB update on Qantas Flight QF30 accident investigation - AircrewBuzz.com, July 28, 2008
• More information released about the Qantas B747 decompression incident - AircrewBuzz.com, July 30, 2008