Low Altitude Flying after diving (same day)

[Charlie99]

I'll give you that, but commercial and private planes aren't subjected to the altitudes required to cause the problems described. I've been through high altitude training with the Air Force and various other agencies. There is no mention of DCS caused by decompression of the cabin in a way comparible to diving. A decompression at cruise altitude isn't going to cause DCS in an acute way that surfacing from even 33' would. No argument on your example and flying at extreme altitudes where pressure suits are required.

This article was written by the FAA office of aviation medicine.

Crude summary: Altitude DCS rare below 18,000 feet except after scuba diving. Low ocurrence rate between 18,000 and 25,000 ft --- an Air Force study reported that only 13% of cases occurred below 25,000' (Of course, the flip side of this statement is that 13% of the cases DID occur below 25,000').

It has a nice table of DCS signs and symptoms.

Since the total free phase volume (bubble volume) is low, most altitude DCS cases are pain only.

One might also note that sea level to 18,000 feet is a 2 to 1 pressure change --- the RATIO originally noted by Haldane in his goat-bending experiments.

I'm surprised that you don't remember being exposed to this information. I believe it is an FAA training requirement for flight crews of any commercial airplane with a ceiling above 25,000.

 

[mempilot]

This article was written by the FAA office of aviation medicine.

Crude summary: Altitude DCS rare below 18,000 feet except after scuba diving. Low ocurrence rate between 18,000 and 25,000 ft --- an Air Force study reported that only 13% of cases occurred below 25,000' (Of course, the flip side of this statement is that 13% of the cases DID occur below 25,000').

It has a nice table of DCS signs and symptoms.

Since the total free phase volume (bubble volume) is low, most altitude DCS cases are pain only.

One might also note that sea level to 18,000 feet is a 2 to 1 pressure change --- the RATIO originally noted by Haldane in his goat-bending experiments.

I'm surprised that you don't remember being exposed to this information. I believe it is an FAA training requirement for flight crews of any commercial airplane with a ceiling above 25,000.

I received my high altitude training from the AF back in 91 and my FAA high altitude endorsement in 88. I agree with the above numbers. If you go back through my posts, I stated that the effects were minor and pretty rare, especially at the altitudes at which general aviation and commercial aircraft operate. During annual recurrent training, we refresh on this information as to the effects on the pilots during a decompression at altitude. All but a structural failure give very little chance of such an incident due to procedures and time to decompress. Structural failures at altitude typically end in disaster in which DCS isn't the issue.

BTW, I've experienced at rapid decompression in the chamber at Offut AFB in Omaha. A little soreness and the effects I mentioned in a previous post. Altidude was 36000'.