Safety Instruction

Discussion in 'Preparedness & Survival' started by RicInOR, Apr 19, 2018.

  1. RicInOR

    RicInOR
    Washington County
    I aim to misbehave Silver Supporter

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  2. CoastRange57

    CoastRange57
    Western Oregon
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    There is maybe 10 minutes of oxygen in the emergency system. An emergency descent has about 8 steps before the descent starts and those happen pretty quick less than a minute. The plane is then manually flown down at least 3,000 feet a minute or as speed permits based upon the structural integrity of the plane and the cause of the decompression. From FL370 it is about a 5 minute or less descent at 250 knots to get to breathable air at 10,000 feet and the manual wants it to be 8,000.

    This flight probably was a bit slower, since you had air frame damage and the engine was all dirtied up and not flowing air very well. She said on the radio she needed to slow down some. The danger of hypoxia is always there at those altitudes but that is the whole purpose of the drop down oxygen masks, to give the pilots time to get the plane down to 10,000 or lower. They are on a separate system so they have plenty.

    But yeah, the masks did those people no good at all.
     
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  3. KKG

    KKG
    Western Washington
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    I would have to guess the Flight Attendants should have been correcting this problem. Of course, that depends on wether or not they were aware of the issue.
     
  4. CoastRange57

    CoastRange57
    Western Oregon
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    An emergency descent is a pretty steep down trim. They were probably belted in and holding on like everybody else. The amount of time they spent in low oxygen levels was pretty minimal and unwinding at 3,000 feet per minute gets you closer to thicker air fast. There is not enough oxygen in the emergency system to last at flight level.

    Friend of mine is a ATP rated pilot and says 10 minutes max on the bottles.
     
  5. Nick Burkhardt

    Nick Burkhardt
    NE Oregon
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    From the publicly available ATC transmissions to/from SWA1380, they only descended to 11,000 at first and maintained that until reaching Philadelphia controlled air space where they were instructed to descend to 6,000. Then a decent to 4,000 and an instruction to maintain an altitude above 3,000 before turning in for approach. Stay above 2,200 over downtown then land.

     
  6. RicInOR

    RicInOR
    Washington County
    I aim to misbehave Silver Supporter

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    Destin talks too much but, this video explains why you need to put your mask on first

    skip ahead to 3:50 for the demo


     
  7. Provincial

    Provincial
    Near Salem, OR
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    Maximum altitude for unpressurized flight for more than 30 minutes without supplimental oxygen is 12,500 ft. (FAR 91.211 (a)(1). Maximum altitude at which every occupant is required to have supplimental oxygen is 15,000 ft. (FAR 91.211(a)(3).

    Note that these are regulations that are very conservative, and survival for periods of one-half hour or more is practical at much greater altitudes. In my estimation, once the aircraft descends below 20,000 ft., all but those with a medical condition or physical limitation that affects their ability to breathe well will have an excellent chance of not being impaired, much less life-threatened while continuing the descent to 15,000 ft. or below. At altitudes above 35,000 ft., people will pass out a short time after loss of pressurization unless they get supplimental oxygen. Above 40,000 ft., loss of conciousness will occur quite rapidly.
     
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