Contract Maintenance

[mweiss]

"Oxygen cannister" is too general a term, which is why I called attention to it. There are two primary types.

The important difference is that there are oxygen cannisters that are simply pressurized oxygen, much like the sort used in PBAs. When they are opened, the oxygen expands, and the container cools due to the expansion.

Had this sort been loaded in the cargo hold, there would have been no ignition source. The result would have been no fire.

Having said this, it still would have been a potential hazard. Had another ignition source existed in the cargo hold, and had it ignited other items in the hold, the fire could have grown sufficiently to burst a cannister before exhausting the oxygen supply in the hold, which would have allowed for more oxygen to feed the fire. Nonetheless, the amount of fuel for the fire would have been significantly lower than it was in the ValuJet case. The airplane would still have had a much better shot at making it back to MIA.

 

[usairways_vote_NO]

I have to disagree. While there are two types of Oxygen canisters as you say. The Maintenance Manual, which is an official controlling document, clearly states that the exact type that were carried as cargo in the cargo hold of Valujet are called Oxygen Generators and/or Canisters. It may be too general a term for your use in this forum but it's use on any type official documents related to their use on md-80's and elsewhere is clearly done and acceptable even when related to this accident.

 

[700UW]

The NTSB concluded that the crash was caused by a fire in the cargo hold fueled by oxygen-generating canisters which had been improperly handled and labeled by SabreTech Corp., the maintenance contractor for ValuJet.

 

[delldude]

The NTSB concluded that the crash was caused by a fire in the cargo hold fueled by oxygen-generating canisters which had been improperly handled and labeled by SabreTech Corp., the maintenance contractor for ValuJet.

[post="258947"][/post]​

last i heard...the 2 mechs and a president were indicted..one offed hisself,the other mech was living with josef mengele in brazil.......

 

[usairways_vote_NO]

Oxygen canister generator tests

Oxygen canister generator tests

 

[mweiss]

While there are two types of Oxygen canisters as you say. The Maintenance Manual, which is an official controlling document, clearly states that the exact type that were carried as cargo in the cargo hold of Valujet are called Oxygen Generators and/or Canisters.

I apologize if I implied that I was drawing a distinction in name. Rather, my intent was to draw a distinction between the two types, as it did make a difference in this case.

Oxygen canister generator tests

The tests that were posed imply that the presence of the oxygen had no impact on the resultant fire. The paper ignores the design of the cargo hold, which intended to smother fires due to consumption of the oxygen initially present in the hold. Given that the generators produced oxygen, the fire never had a chance to be smothered.

Furthermore, the tests illustrated how close to combustion temperature the cannister was able to get. What was not tested was the candle ignition temperature, so as to determine if a chain reaction among generators was achievable, and, further, if it was, what temperature of several reacting in concert would result.

 

[usairways_vote_NO]

Apology accepted. By this statement you made

"Not canisters. As BB said, it was generators. This difference is important."

I thought you were saying I used a term that was not correct for the canisters that were in the hold and I was calling them something that they wern't. But nothing could be further from the truth.

I won't comment on the canister tests as I just offered it for reading.

I will say though while it is somewhat true Class D cargo holds were designed to, I use this term loosely, smother a fire, they were more correctly designed to contain a fire. As the compartments are NOT completely sealed off from oxygen sources as may be implied by the smother statement. The holds (DC-9 MD-80) are pressurized can be heated and the compartments have to be equalized by some means to other areas of aircraft.

 

[mweiss]

I agree; Class D holds aren't exactly ideal examples of designing to starve fires. Ultimately, it always comes down to money, though, doesn't it?

 

[usairways_vote_NO]

Well it always is.... but if I am not mistaken Class D, if they are still called that, are required to have have fire detection and fire suppression installed as an after effect of Valujet accident.