How High Can I Fly After Scuba Diving?

[GCullen94]

Here is a PPO2 curve representing O2 partial pressure drop off from atmospheric pressure (PPO2 of 160mmHg) and can be assumed nitrogen would behave in the same way (total atm pressure at MSL 760 mmHg) meaning pressure would drop from 760 to 640 mmHg, or roughly 15% (where bubble sizes would increase 15%)

The pressure changes at depth = 23mmHg/ft
30 feet per minute= 11.5 mmHg/s
11.5mmHg/s= climb rate (plane) of 24,000 ft/min (climb rate no factor as no plane is climbing this quickly)

Basically keep your dives shorter using altitude diving tables, plan them like you are diving at cruising altitude.

 

[Mr Carcharodon]

Do you even dive? Or are you just being silly?

So...2000 feet above sea level is 30.7 fswa. That is missing a stop by 2.3 fsw, assuming you have an airplane waiting right at the beach. I won’t tell you what to do but if you want to head to the airport several hours later and are worried about two feet on your decompression profile your right action is to wait. Not everyone does worries about that and we still seem to be kicking. You can make your own risk assessment.

 

[tphelps]

Do you require your divers to use tables?
If they use computers, how do they use these protocols?

For our Campus Recreation Department, we use dive tables. We do have dive computers that students use, but they serve as digital depth gauges.

Per the UH Diving Safety Manual, any dive conducted with a dive computer requires a 4 hour surface interval before ascending to 3,000ft elevation. This is why most the time UH dive plans use NAUI tables.

 

[lerpy]

As a diver and a pilot I would personally not do this, I think you are taking an undue risk. you can say you are going to maintain 2000' through the entirety of your flight, however there may be circumstances that require you to go higher. If you are flying through an ATC zone as you know you could be requested to change altitude. It seems like you are taking an approach of calculating how much risk you can add, rather than how much risk you can remove.

 

[tlj3071]

Here is a link to a discussion several years ago http://www.scubaboard.com/community/threads/dive-and-fly.220055/#post-4917034 in which I asked exactly the same question. Basically, why I could not just treat the surface as a simple decompression stop. The math would seem to indicate that it should be possible to complete an NDL dive, jump on the floats of a small plane, and immediately take off and fly at some (low) altitude. The consensus (and the response from Dr. D, and also from DAN) was "just say no". There is not enough physiological evidence to allow this behavior.

 

[certifiedsnorkermaster]

however there may be circumstances that require you to go higher. If you are flying through an ATC zone as you know you could be requested to change altitude. It seems like you are taking an approach of calculating how much risk you can add, rather than how much risk you can remove.

You never have to comply with an ATC request if it will make your flight unsafe. A simple "unable" response will work.

 

[maj2]

I cannot comment directly, since the flight profile (i.e. altitude) described is well outside of my (single) experience. I will, however, share my experience with flying in a small aircraft shortly after diving...

On a trip to South Africa in 2010, the game lodge that we were staying at offered a diving day trip to Sodwana Bay, so naturally I wanted to do it. The plan was about a six-seater and picked us up from the airstrip at the lodge and took us to Sodwana Bay. Total flight time was 20 minutes or less. After the dives, I got an hour or two to enjoy the beach and some lunch with the rest of my family and then we were flown back.

The pilot in my case was familiar with DCS, knew I had been diving, and was very good about describing his flight plan. He was sticking to an altitude of around 750ft for the short flight back (versus 1,000ft-1,200ft for the flight there), and would fly lower if I felt any symptoms. I also got to ride "shotgun" in the bush plane so the pilot could see me and make any communication faster/easier. All was good, but 750ft is a far cry from the altitude described in the OP. I also assume that this pilot was flying in presumably less regulated airspace and might not have been able to fly that low in other jurisdictions.

I had a great time diving that day, and would not hesitate to do it again should the opportunity arise. However, I would be very hesitant to try the same with much more altitude.

 

[lerpy]

You never have to comply with an ATC request if it will make your flight unsafe. A simple "unable" response will work.

Well yes as you say you can tell ATC that you cannot comply if it will jeopardize the flight or someone onboard. I guess my logic is, if you cannot respond to ATC as that would be putting the flight at risk because you were diving, then in essence the flight is at risk before you even leave that ground. Before you leave the ground you know there is a risk and therefore you may not be able to comply, so maybe don't leave the ground.

Frankly it seems like you are starting to compound risk and willing to side step measures in place meant for safety. All studies indicate you should not fly directly after flying, except in cases of emergencies where the flight crew is medically trained and is evac-ing to a chamber. Second you are taking the approach that you will simply tell ATC you cannot comply, sidestepping another safety mechanism. To me as a pilot telling ATC you cannot comply is very serious and is normally used in extreme or emergency situations. You not complying with ATC may not put a controller in a position where they need to quickly re-route other aircraft to avoid you. I feel that you are adding undue risk to your trip. Just my two cents.

 

[Altamira]

A very realistic scenario: I am the captain of a twin engine aircraft that is planning on flying you (the diver) from A to B at 1500-2000 above sea level for an hour flight after you finished diving for the day. Assuming that I know your situation, and also being a diver, I would first try to dissuade you from taking the flight, pointing out all of the risks.. If you insisted on taking the flight, I would try to stay at low altitude. However, let's throw in an engine failure enroute to B, and as the Captain, am I going to stay at low level for your sake, or am I going to climb to the highest altitude possible to deal with my inflight emergency, improve my communication range, and put as much time and distance between the aircraft and the rock hard sea? If you think that is going to be a difficult decision for me, or the decision would be in your favor, you would be wrong. Even if it was just the two of us onboard, I am going to climb, and would not think twice about that decision. Just because you might be willing to accept increased risk to your own body, don't expect others to put themselves in harms way because of your decisions.

 

[Basking Ridge Diver]

As a pilot - you would be making a poor choice. You are over water you will need to ditch in the water why on earth would you climb?