Qantas 744 Depressurisation

[Short_Circuit]

The installation strap have a spring to allow for expansion / contraction.

The release clip is safetied with a pin.

But anything is possible.

[geemul]

Might be worth a read for known failures of aluminium (in statistically insignificant numbers) SCUBA and rescue type cylinders.

Luxfer: Technical Bulletins: October 22, 2007

These units develop neck cracks up into the thread region and have been known (again in statistically insignificant numbers) to expel valves at high velocity. Most of these cylinders have been condemned at their regular inspection cycles.

These are most likely different styles of cylinders and different grades of aluminium to the ones on aircraft and are treated far worse than aircraft kit.

Like the car photo's, it's just an illustration of what can happen in this world.

[pacplyer]

No, but it was a modern car, which has to pass modern safety standards, made of steel, not thin aluminum alloy. I'm sure if you sealed it up properly, took care of the windows, it would be able to stand much higher pressure than a 747.

Certainly, Soupman,

Your rebuttal sounds fair. But may I point out, a flaw in that argument. A modern automobile in compliance with modern DOT highway safety standards is not designed to withstand pnematic expansion forces from within the vehicle. That's why it flew apart so dramatically. It is only designed (with any significant magnitude) to withstand the opposite: external compression and energy absorption from outside the vehicle (a crash.)

You guys are mixing apples and Oranges imho. The material chosen for design is not the only factor in strength. The Toyota in that picture (not some "Chitty-Chitty-Bang-Bang" sealed window pickup you've imagined) is incapable of being pressurized. Ergo, the damage we see in the photo is not representative of what would happen in a reverse stress-engineered structure like a 747 pressure containment hull.

This is why aeronautical engineering is quite a different thing altogether than engineering the stresses involved in a simple soup-can (even a four wheel drive one from Japan.)

Granted, I will concede that IF the cylinder itself goes off that close to the 747 skin and fuselage structure: we are going to loose some skin baby. Thank God for great aeronautics aloft in Boeing Aircraft (built like tanks.) They've repeatedly come home safe with huge portions of the aircraft gone.

Repeat after me everybody: "If it's not Boeing, I'm not Going."

Vortsa is dead-balls-on imho with his post, BTW. And agree with his preventative failure post below as well;

Aviation post-accident/incident investigation, however, does factor stats in for likelyhood, but does not rule out anything outside those stats. If the evidence leads off in a certain unlikely direction (like the DC-10 #2 eng uncontained N1 hub failure, or structural O2 cylinder failure) then the industry has changed and new AD's NPRM's etc result.

[vortsa]

"The problem is that your "cylinder failure theory" is statistically unheard of in reported jet aviation history of over fifty years."

That's not the way we work in Aviation, we look for a potential problem and try to address it before it becomes an event.

see below

Compliance: 1. Before 28 February 2005
2. After 26 February 2004
Effective Date: 26 February 2004
DCA/EMY/27A Oxygen Reserve Cylinders – Inspection and Replacement
Applicability: Oxygen Cylinders P/Ns GLF(XXX)-(X), GLD(XXX)-(X), PC2300 and SLF300, which
are known to be installed on, but not limited to Airbus A300 series aircraft, Dassault
Aviation (AMD-BA) Mystère-Falcon 20, Mystère-Falcon 50, Falcon 200 and Falcon
900 aircraft, Pilatus aircraft, Eurocopter SA 315 B and AS 350 B3 helicopters and
Hindustan Aeronautics Limited helicopters.
Note 1: This AD has been revised to extend the compliance time for oxygen cylinders
operated in normal climatic conditions from 6 months to 12 months.
Note 2: These types of oxygen cylinders are an optional equipment fit for use during
operations at high altitudes or to provide respiratory aid for passengers.
Requirement: To prevent oxygen cylinders exploding due to aging and deterioration of the
Aluminium Alloy 5283 (AA5283) cylinder shell material, identify the year of
manufacture of each affected P/N oxygen reserve cylinder made from AA5283 and
replace per the instructions in Eurocopter AS 350 Alert Service Bulletin No. 05.00.54.
Immediately after removing the oxygen cylinder from the aircraft, empty the cylinder
per the instructions in Intertechnique Service Bulletin (SB) GLD/GLF-35-150 dated 20
September 2006.
Note 3: Oxygen cylinders with P/Ns listed in this AD may only be used if the service life is
within the limitations of the compliance of this AD.
Note 4: Oxygen cylinders with P/Ns listed in this AD and which are held as spares are to be
inspected per the requirements of this AD. Identify the year of manufacture of the
cylinder and empty all oxygen reserve cylinders that have reached or exceeded 2

[Deaf]

One point that has to be borne in mind with the assorted horror pics etc is the dynamic behavior of metal cracks with gas pressure. A crack normally propagates slowly with fatigue etc. When it gets to a certain length (dependant on material, stress etc) it will propagate at 1/3 speed of sound in metal ie much faster than pressure relief which happens at the speed of sound in gas.

Thus if something like Al skin designed for a few psi pressure suddenly get hit with a slug of gas at high velocity there will be a localised pressure which well may cause the skin to fail and the crack will spread very fast. The airflow does the rest.

Poor explanation I know but modelling this sort of thing is not easy.

[Pontius Navigator]

Pax Masks Adjustment

It was said many pax masks were not adjusted.

Maybe the pax were happy to hold the mask in place, much as is see on many hospital dramas? It gives them something to do with one hand.

If you have never donned an oxygen mask before you may not have the confidence to fiddle around with the straps and then let go in what you may perceive as a d***h dive.

How many of you when you were first trained got any sort of mask on right first time? and how many had to be assisted?

IMHO holding a mask in place with one hand is a smart move.

[pacplyer]

Vortsa,

I concede the point to you. O2 problems are tracked and prevented.

You guys so a great job of making flying safe.

pac

[Machaca]

Pacplyer

The problem is that your "cylinder failure theory" is statistically unheard of in reported jet aviation history of over fifty years. We can't find one case of this ever happening in millions of flight hours.)

Well, er, not quite. I did a quick search a few days ago and found a similar incident from 2006 -- cylinder rupture & pressure hull penetration. I even shared it back in post #678, with a link to the AAIB bulletin.


Reported, but unheard of by all but a few.

[BOAC]

No wish to restart any wild theories about TWA800, and I apologise for not reading all the posts here, but does anyone know if the 'inconclusive' accident findings looked at bottle explosion, or even if the initial rupture was near any bottles? This from a PPrune archive:

<‘AAR-00/03 "It was clear from the wreckage recovery locations that the FIRST pieces to depart the airplane were from the area in and around the airplane's wing center section (WCS), which includes the CWT, and therefore that the breakup must have initiated in this area.”

That statement refuted by TWA 800 public docket:: Docket Number SA-516, Exhibit No. 22A, Trajectory Study, page 3: "The wreckage distribution shows that parts were initially shed from the area just forward of the wing."

"...the red zone (the wreckage zone closest to JFK along the airplane's flightpath and, therefore, containing the earliest pieces to depart the airplane) consisted primarily of pieces from the WCS front spar and spanwise beam (SWB) 3, the manufacturing access door from SWB 2, the two forward air conditioning packs, large pieces of a ring of fuselage structure just in front of the wing front spar, and main cabin floor beams and flooring material from above the WCS and from the fuselage in front of the WCS....

The forward cargo door is ‘from the fuselage in front of the WCS....’>

There was also a recent thread in this forum about TWA800 which is now here.

I am braced for the howls of protest!

[pacplyer]

Thanks Machaca.

I missed your post
BUT.....

It's not an oxygen cylinder if I read your link correctly. The pic on page 13 is a completely different animal: a (machined out of solid bar stock) metal relatively Low pressure (1000 psi IIRC) back up to normal 2000-3000 psi hydraulics (IIRC generally speaking)

Hydraulic accumulator information
There are two hydraulic accumulators located under
the BAe 146 fuselage floor close to the main landing
gear installation and inside the pressure hull, and these
are fitted so that the hydraulic system can cope with
fluctuations in demand. The accumulator consists of a
pressure cylinder with a piston inside. On one side of
the piston is hydraulic fluid and on the other is nitrogen,
nominally at 1,000 psi.

That's how I read it anyway. Are Metal O2 tanks stamped out of thick sheets and then welded at the neck? Not sure.

Machaca, great photos; you are one of the best contributors to this thread thanks.

[Machaca]

All Avox Systems lightweight steel 801307 series cylinders that apply to Boeing aircraft meet DOT 3HT-1850 regs.

Title 49: Transportation
PART 178—SPECIFICATIONS FOR PACKAGINGS


§ 178.44 Specification 3HT seamless steel cylinders for aircraft use

(a) Type, size and service pressure. A DOT 3HT cylinder is a seamless steel cylinder with a water capacity (nominal) of not over 150 pounds and a service pressure of at least 900 psig.

(b) Authorized steel. Open hearth or electric furnace steel of uniform quality must be used. A heat of steel made under the specifications listed in Table 1 in this paragraph (b), a check chemical analysis that is slightly out of the specified range is acceptable, if satisfactory in all other respects, provided the tolerances shown in Table 2 in this paragraph (b) are not exceeded. The maximum grain size shall be 6 or finer. The grain size must be determined in accordance with ASTM E 112–88 (IBR, see §171.7 of this subchapter). Steel of the following chemical analysis is authorized:

Table 1 — Authorized Materials

..........................AISI 4130
Designation............(percent)

Carbon.................0.28/0.33
Manganese...........0.40/0.60
Phosphorus...........0.040 maximum
Sulfur..................0.040 maximum
Silicon.................0.15/0.35
Chromium.............0.80/1.10
Molybdenum..........0.15/0.25


Table 2 — Check Analysis Tolerances

.........................................................Tolerance %
Element..........Limit or max %............over max.....under min

Carbon...........Over 0.15 to 0.40 incl.....03............04
Manganese.....To 0.60 incl...................03............03
Phosphorus*...All ranges.....................................01
Sulphur..........All ranges.....................................01
Silicon...........To 0.30 incl...................02............03
...................Over 0.30 to 1.00 incl......05............05
Chromium......To 0.90 incl....................03............03
...................Over 0.90 to 2.10 incl......05............05
Molybdenum...To 0.20 incl...................01............01
...................Over 0.20 to 0.40 incl......02............02

*Rephosphorized steels not subject to check analysis for phosphorus.

(c) Identification of material. Material must be identified by any suitable method. Steel stamping of heat identifications may not be made in any area which will eventually become the side wall of the cylinder. Depth of stamping may not encroach upon the minimum prescribed wall thickness of the cylinder.

(d) Manufacture. Cylinders must be manufactured using equipment and processes adequate to ensure that each cylinder produced conforms to the requirements of this subpart. No fissure or other defect is permitted that is likely to weaken the finished container appreciably. The general surface finish may not exceed a roughness of 250 RMS. Individual irregularities such as draw marks, scratches, pits, etc., should be held to a minimum consistent with good high stress pressure vessel manufacturing practices. If the cylinder is not originally free of such defects or does not meet the finish requirements, the surface may be machined or otherwise treated to eliminate these defects. The point of closure of cylinders closed by spinning may not be less than two times the prescribed wall thickness of the cylindrical shell. The cylinder end contour must be hemispherical or ellipsoidal with a ratio of major-to-minor axis not exceeding two to one and with the concave side to pressure.

(e) Welding or brazing. Welding or brazing for any purpose whatsoever is prohibited, except that welding by spinning is permitted to close the bottom of spun cylinders. Machining or grinding to produce proper surface finish at point of closure is required.

(f) Wall thickness.
(1) Minimum wall thickness for any cylinder must be 0.050 inch. The minimum wall thickness must be such that the wall stress at the minimum specified test pressure may not exceed 75 percent of the minimum tensile strength of the steel as determined from the physical tests required in paragraph (m) of this section and may not be over 105,000 psi.
(2) Calculations must be made by the formula:
S = [P(1.3D2 + 0.4d2 )] / (D2 − d2 )
Where:
S = Wall stress in psi;
P = Minimum test pressure prescribed for water jacket test;
D = Outside diameter in inches;
d = Inside diameter in inches.
(3) Wall thickness of hemispherical bottoms only permitted to 90 percent of minimum wall thickness of cylinder sidewall but may not be less than 0.050 inch. In all other cases, thickness to be no less than prescribed minimum wall.

(g) Heat treatment. The completed cylinders must be uniformly and properly heated prior to tests. Heat treatment of the cylinders of the authorized analysis must be as follows:
(1) All cylinders must be quenched by oil, or other suitable medium.
(2) The steel temperature on quenching must be that recommended for the steel analysis, but may not exceed 1750°F.
(3) The steel must be tempered at a temperature most suitable for the particular steel analysis but not less than 850°F.
(4) All cylinders must be inspected by the magnetic particle or dye penetrant method to detect the presence of quenching cracks. Any cylinder found to have a quenching crack must be rejected and may not be requalified.

(h) Openings in cylinders and connections (valves, fuse plugs, etc.) for those openings. Threads conforming to the following are required on openings:
(1) Threads must be clean cut, even, without cracks, and to gauge.
(2) Taper threads, when used, must be of length not less than as specified for National Gas Tapered Thread (NGT) as required by American Standard Compressed Gas Cylinder Valve Outlet and Inlet Connections.
(3) Straight threads having at least 6 engaged threads are authorized. Straight threads must have a tight fit and a calculated shear stress of at least 10 times the test pressure of the cylinder. Gaskets, adequate to prevent leakage, are required.

(i) Hydrostatic test. Each cylinder must withstand a hydrostatic test, as follows:
(1) The test must be by water-jacket, or other suitable method, operated so as to obtain accurate data. Pressure gauge must permit reading to an accuracy of 1 percent. The expansion gauge must permit reading of total expansion to an accuracy either of 1 percent of 0.1 cubic centimeter.
(2) Pressure must be maintained for at least 30 seconds and sufficiently longer to ensure complete expansion. Any internal pressure applied after heat treatment and previous to the official test may not exceed 90 percent of the test pressure. If, due to failure of the test apparatus, the test pressure cannot be maintained, the test may be repeated at a pressure increased by 10 percent or 100 psig, which ever is the lower.
(3) Permanent volumetric expansion may not exceed 10 percent of total volumetric expansion at test pressure.
(4) Each cylinder must be tested to at least5/3times service pressure.

(j) Cycling tests. Prior to the initial shipment of any specific cylinder design, cyclic pressurization tests must have been performed on at least three representative samples without failure as follows:
(1) Pressurization must be performed hydrostatically between approximately zero psig and the service pressure at a rate not in excess of 10 cycles per minute. Adequate recording instrumentation must be provided if equipment is to be left unattended for periods of time.
(2) Tests prescribed in paragraph (j)(1) of this section must be repeated on one random sample out of each lot of cylinders. The cylinder may then be subjected to a burst test.
(3) A lot is defined as a group of cylinders fabricated from the same heat of steel, manufactured by the same process and heat treated in the same equipment under the same conditions of time, temperature, and atmosphere, and may not exceed a quantity of 200 cylinders.
(4) All cylinders used in cycling tests must be destroyed.

(k) Burst test. One cylinder taken at random out of each lot of cylinders must be hydrostatically tested to destruction.

(l) Flattening test. A flattening test must be performed on one cylinder taken at random out of each lot of 200 or less, by placing the cylinder between wedge shaped knife edges having a 60° included angle, rounded to1/2-inch radius. The longitudinal axis of the cylinder must be at a 90-degree angle to knife edges during the test. For lots of 30 or less, flattening tests are authorized to be made on a ring at least 8 inches long cut from each cylinder and subjected to same heat treatment as the finished cylinder.

(m) Physical tests. A physical test must be conducted to determine yield strength, tensile strength, elongation, and reduction of area of material, as follows:
(1) Test is required on 2 specimens cut from 1 cylinder taken at random out of each lot of cylinders.
(2) Specimens must conform to the following:
(i) A gauge length of at least 24 times the thickness with a width not over six times the thickness. The specimen, exclusive of grip ends, may not be flattened. Grip ends may be flattened to within one inch of each end of the reduced section. When size of cylinder does not permit securing straight specimens, the specimens may be taken in any location or direction and may be straightened or flattened cold by pressure only, not by blows. When specimens are so taken and prepared, the inspector's report must show in connection with the record of physical tests detailed information in regard to such specimens.
(ii) Heating of a specimen for any purpose is not authorized.
(3) The yield strength in tension must be the stress corresponding to a permanent strain of 0.2 percent of the gauge length.
(i) The yield strength must be determined by either the “offset” method or the “extension under load” method as prescribed in ASTM E 8 (IBR, see §171.7 of this subchapter).
(ii) In using the “extension under load” method, the total strain (or “extension under load”) corresponding to the stress at which the 0.2 percent permanent strain occurs may be determined with sufficient accuracy by calculating the elastic extension of the gauge length under appropriate load and adding thereto 0.2 percent of the gauge length. Elastic extension calculations must be based on an elastic modulus of 30,000,000. In the event of controversy, the entire stress-strain diagram must be plotted and the yield strength determined from the 0.2 percent offset.
(iii) For the purpose of strain measurement, the initial strain must be set while the specimen is under a stress of 12,000 psi, the strain indicator reading being set at the calculated corresponding strain.
(iv) Cross-head speed of the testing machine may not exceed1/8inch per minute during yield strength determination.

(n) Magnetic particle inspection. Inspection must be performed on the inside of each container before closing and externally on each finished container after heat treatment. Evidence of discontinuities, which in the opinion of a qualified inspector may appreciably weaken or decrease the durability of the cylinder, must be cause for rejection.

(o) Leakage test. All spun cylinders and plugged cylinders must be tested for leakage by dry gas or dry air pressure after the bottom has been cleaned and is free from all moisture, subject to the following conditions and limitations:
(1) Pressure, approximately the same as but not less than service pressure, must be applied to one side of the finished bottom over an area of at least1/16of the total area of the bottom but not less than3/4inch in diameter, including the closure, for at least one minute, during which time the other side of the bottom exposed to pressure must be covered with water and closely examined for indications of leakage. Except as provided in paragraph (q) of this section, a cylinder must be rejected if there is leakage.
(2) A spun cylinder is one in which an end closure in the finished cylinder has been welded by the spinning process.
(3) A plugged cylinder is one in which a permanent closure in the bottom of a finished cylinder has been effected by a plug.
(4) As a safety precaution, if the manufacturer elects to make this test before the hydrostatic test, the manufacturer should design the test apparatus so that the pressure is applied to the smallest area practicable, around the point of closure, and so as to use the smallest possible volume of air or gas.

(p) Acceptable results of tests. Results of the flattening test, physical tests, burst test, and cycling test must conform to the following:
(1) Flattening required without cracking to ten times the wall thickness of the cylinder.
(2) Physical tests:
(i) An elongation of at least 6 percent for a gauge length of 24 times the wall thickness.
(ii) The tensile strength may not exceed 165,000 p.s.i.
(3) The burst pressure must be at least4/3times the test pressure.
(4) Cycling-at least 10,000 pressurizations.

(q) Rejected cylinders. Reheat treatment is authorized for rejected cylinders. Subsequent thereto, cylinders must pass all prescribed tests to be acceptable. Repair by welding or spinning is not authorized. For each cylinder subjected to reheat treatment during original manufacture, sidewall measurements must be made to verify that the minimum sidewall thickness meets specification requirements after the final heat treatment.

(r) Marking. (1) Cylinders must be marked by low stress type steel stamping in an area and to a depth which will insure that the wall thickness measured from the root of the stamping to the interior surface is equal to or greater than the minimum prescribed wall thickness. Stamping must be permanent and legible. Stamping on side wall not authorized.
(2) The rejection elastic expansion (REE), in cubic cm (cc), must be marked on the cylinder near the date of test. The REE for a cylinder is 1.05 times its original elastic expansion.
(3) Name plates are authorized, provided that they can be permanently and securely attached to the cylinder. Attachment by either brazing or welding is not permitted. Attachment by soldering is permitted provided steel temperature does not exceed 500 °F.

(s) Inspector's report. In addition to the requirements of §178.35, the inspector's report must indicate the rejection elastic expansion (REE), in cubic cm (cc).
[Amdt. 178–114, 61 FR 25942, May 23, 1996, as amended at 62 FR 51561, Oct. 1, 1997; 65 FR 58631, Sept. 29, 2000; 66 FR 45385, Aug. 28, 2001; 67 FR 51652, Aug. 8, 2002; 68 FR 75748, 75749, Dec. 31, 2003]

[Machaca]

pacplyer

Are Metal O2 tanks stamped out of thick sheets and then welded at the neck?

Deep-drawn and hot-spun -- have a look!

[Machaca]

Dodgy cylinder maintenance has happened before:

http://www.ntsb.gov/Recs/letters/1995/A95_148.pdf

A review of the oxygen cylinder's maintenance records indicated that it had been serviced by Tec-Air Services, Incorporated's (Tec-Air), East Northport, New York, repair station on November 30, 1990, and again at Tec-Air's Macon, Georgia, repair station on January 11, 1994. According to Tec-Air records, the service included removing the cylinder valve, inspecting and cleaning the cylinder's interior, testing the cylinder hydrostatically, cleaning and overhauling the cylinder valve, purging/recharging the cylinder, and checking for leakage.

The operator of N66JE, Professional Jet Management, reported that the oxygen cylinder in another of its corporate jet airplanes, a Hawker Siddeley 125-700A, had also been serviced by Tec-Air, but upon reinspection was found unserviceable because of internal corrosion.

In December 1994, the Federal Aviation Administration (FAA) inspected Tec-Air's East
Northport facility, Repair Station No. MAlR315K, and found that Tec-Air had violated or failed to demonstmte compliance with 10 sections of the Federal Aviation Regulations relating to Parts 21, 43, and 145. The investigation cited numerous occasions on which Tec-Air had approved oxygen cylinder assemblies and aircraft fire extinguishers for return to service, including parts utilized on passenger-carrying aircraft under Part 121, when such equipment was unairworthy.

Based on Tec-Air's inadequate record system, it could not be determined whether Tec-Air replaced parts as required during overhaul, utilized old parts, or changed the parts at all.

---

http://www.dot.gov/affairs/cair.htm

FOR IMMEDIATE RELEASE OIG 28-95
Friday, October 27, 1995 Contact: Todd Zinser
Tel.: [phone]

DOT INSPECTOR GENERAL ANNOUNCES
GUILTY PLEA IN AIRCRAFT EMERGENCY
EQUIPMENT FRAUD CASE


Inspector General A. Mary Schiavo of the U.S. Department of

Transportation today announced that Tec-Air Services, Inc., and

two of its top executives pled guilty to charges of conspiracy,

mail fraud and making false statements to the federal government

in connection with a long-running fraudulent scheme involving the

failure to properly service aircraft emergency equipment.

Tec-Air Services, Inc. (Tec-Air), based in East Northport,
Long Island, and its two vice presidents, Jack Caloras and Steven
Metal, pled guilty on Oct. 12 to five felony counts before U.S.
District Judge Jacob Mishler in Uniondale, N.Y.

Tec-Air was an aircraft repair station licensed by the
Federal Aviation Administration (FAA) to service emergency
equipment such as fire extinguishers, smoke detectors and the
oxygen supply system used during emergency cabin depressurization
on commercial aircraft.

The charges relate to Tec-Air's failure, between 1990 and
1994, to properly test, overhaul and repair aircraft emergency
equipment for customers who were primarily civilian airlines. In
order to reduce costs and increase profits, Tec-Air, at the
direction of Caloras and Metal, routinely failed to properly test
the emergency equipment for defects or to replace needed parts as
required by the manufacturers' specifications and by FAA
regulations. Tec-Air billed its customers for the services
although they were not performed. Tec-Air then falsified
documents to indicate the required testing and repair work had
been performed.

The defendants also pled guilty to mail fraud for failing to
properly overhaul and replace necessary parts in the oxygen
system emergency equipment provided to one of their customers,
Boeing Defense and Space Group, for use on Air Force One and Air
Force Two, the aircraft used to transport the President and Vice
President.

Caloras and Metal face a maximum sentence of five years in
prison and a $250,000 fine on each count. As part of their plea
agreement with the government, they have each agreed to pay a
fine and to be barred for life from operating or being employed
at any business that holds an FAA license.

Tec-Air faces a maximum fine of $500,000 on each count. As
part of its plea agreement, Tec-Air has agreed to pay a $100,000
fine and to be permanently barred from holding any FAA license.

The trial of another defendant named in the superseding
indictment, Domenick Leonardi, who was Tec-Air's production
coordinator, is scheduled to begin on Nov. 13.

The case was investigated by DOT's Office of Inspector
General in New York, N.Y., the Federal Bureau of Investigation
and the Defense Criminal Investigative Service.

The prosecution was handled by Assistant U.S. Attorneys Sean
F. O'Shea and Ronald G. White and former Assistant U.S. Attorney
Mark S. Cohen, of the U.S. Attorney's Office for the Eastern
District of New York.

[pacplyer]

Interesting stuff Machaca,

Especially the bottle inspection pencil whipping. Can in fact cause fires since the tank contamination plus oxidizer (oxygen) is dispersed together when old flying leatherman sets off an ignition source (static) in that corporate jet case.

You're getting really warm buddy, I'll give you that. Still no documented oxygen tank failure.

(But don't give up now! You're bound to find one if anybody can.)

[DozyWannabe]

pacplyer:
Thank God for great aeronautics aloft in Boeing Aircraft (built like tanks.) They've repeatedly come home safe with huge portions of the aircraft gone.

Repeat after me everybody: "If it's not Boeing, I'm not Going."

Now now, that's not exactly fair - the DHL Airbus A300 landed successfully after a sodding missile took out a significant chunk of the port wing's trailing edge and the hydraulics to boot!

That said, hats off to any aircraft manufacturer that builds beasts that can take that kind of punishment and still bring you home.

[airship]

You guys are mixing apples and Oranges imho. The material chosen for design is not the only factor in strength. The Toyota in that picture (not some "Chitty-Chitty-Bang-Bang" sealed window pickup you've imagined) is incapable of being pressurized. Ergo, the damage we see in the photo is not representative of what would happen in a reverse stress-engineered structure like a 747 pressure containment hull.

Is that why apparently solid houses literally "explode" when a tornado passes overhead? Is that why human-beings suffer 'the bends' if they don't respect the proper depth/time tables when ascending? Is that why fish caught at great depths have never been brought up to the surface alive (even those that are hooked at depths of a mere 100m. will end up with their gas-bladders in their mouths and succomb rapidly)...?! You're missing the point. Which is that we're discussing an almost instantaneous escape of highly-pressurised gas locally and in a relatively-confined space, leaving no appreciable time for a normal (or natural) equilibrium to reinstate itself...?! Perhaps, we're all (aircraft and living creatures) more fragile than you might think...?!

[Wingover68]

A slight deviation from the very informed ongoing technical discussion. I can’t remember which but one of the ATSB’s safety investigation reports during the past 6 months or so included the statement “Sooner or later it will happen, as long as the probability is greater than zero”

Well said I thought, and stuck it on my computer desktop as a reminder that zero probability could be a bit elusive.

[airship]

All the examples you site are not metal machines at 29,000 feet.

At least one of the examples I cited involved a naturally-occuring phenomenom that are normally associated with cumulonimbus, a type of cloud that can be found anywhere between 2,000 - 16,000 meters altitude. If you need any help making the conversion or otherwise, please do contact Duck Rodgers!

[Conan The Barber]

In threads like this one, there is always at least one poster who becomes a bit too prolific and a bit too possessive.

Taking a bit of time off for some reflection, is good for both poster and thread.

[airship]

Well, I'm off to feed the stray cats now anyway.