How High Can I Fly After Scuba Diving?

[Altamira]

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?

Poor choice: Don't think so! I am a retired career Air Force and retired major airline pilot, and I will assume you did not actually read the post with understanding. A twin engine airplane has two engines, so if one malfunctions, you are not going to be ditching unless the second one quits also. Even if I was in a single engine aircraft, I would gladly exchange excess airspeed for increased altitude to get maximum altitude at best glide speed, no matter the DCS risk to the diver passenger. Airplanes, even big ones, are able to glide some distance even if all engines are lost and you are able to keep the aircraft under control (ask Capt. Sully Sullenberger of Miracle on the Hudson fame). In such an unfortunate and dire situation, altitude and time are your friends--proximity to the ground and reduced time to impact/ditch are your enemies. Altitude and time provide you the opportunity to run emergency checklists and hopefully correct the problem, as well make emergency communications letting as many people know who and where you are, and the nature of your emergency. If you have to ditch in the sea, you want as much time to get that set up because it is not easy under the best of circumstances, and can be disastrous with even minor mistakes.

Divers can, and do, unnecessarily put themselves at risk by flying too soon after diving because they do not think about or understand all the problems that can occur in flight, nor do they know or understand what pilots are trained to do in emergencies. To me, these divers are in the same category as "trust me" dives in an overhead environment without proper training or equipment. They don't know what they don't know!

 

[Basking Ridge Diver]

Where I am headed is you took the risk by taking that passenger on board knowing the situation - I think you owe that passenger a fiduciary duty. Over land I understand gaining altitude - but water I believe you are not gaining more than you are risking YMMV...

But as you said "no matter the DCS risk" - I won't be flying with you...

Lots of other pilots out there.

 

[Altamira]

I have tried to explain just one scenario, among many, where the flight might not be able to stay at a planned low altitude as another piece of information to help divers make a more intelligent and informed decision when considering the increased risk of a DCS hit when bending/breaking the dive/fly guidelines. If you choose to put yourself at additional risk, that is obviously an individual's decision. However, I think it is narcissistic to think it is OK to shift that decision making process, and any poor outcomes that may come your way, to others or expect other people to accept potential increased risk to themselves because of your poor decisions.

As far as my analysis of what would likely happen in the scenario I described in my post above, my comments are based on 35 years of flying aircraft as diverse as single engine Cessna, to Air Force fighters, to commercial jet airliners. You can be the judge of who has expertise in this area and who does not.

 

[OldPhotog]

Altamira is correct, and he's the guy I'd want to fly with. If you have a functioning engine and the ability to climb, climb and let's fly to an airport or a nice flat, piece of land. This is in spite of the old saying that if you lose one engine in a twin-engine airplane, you can fly on the remaining engine to the scene of the crash.

 

[JohnnyC]

Altamira is right. Just sayin'....

 

[John C. Ratliff]

It has been a long while since I dealt with diving/altitude/flying issues (1970s). But let me tell you a few stories. Before I do that, let me say that if flying after diving is a problem, it is because of PPP.

When we dove in Clear Lake, Oregon at 3500 feet altitude, but would need to drive home over the pass at 5500 feet, we used the 5500 foot altitude for our dive planning,

When in the USAF for dives at San Nicholas Island, I pulled the divers to the surface at 12 hours before our planned takeoff time home on a HC-130 aircraft.

Now, here's a question. If you need to dive prior to flying (within 12 hours), why cannot you program your computers or use the altitude dive tables as if you were diving at 10,000 feet? Commercial flights will always be pressurized below 10,000 feet, as above that number people need to be on oxygen. The same applies to light planes, which don't carry oxygen on board. These planes usually fly VFR (visual flight rules), and FAA rules may require that a VFR plane climb to avoid instrument rules when encountering weather. 'Just a thought.

By the way, Altamira above is correct; DCI is a delayed emergency which can usually be dealt with. But a ditching at sea usually is a fatal accident.

SeaRat

 

[Altamira]

It has been a long while since I dealt with diving/altitude/flying issues (1970s). But let me tell you a few stories. Before I do that, let me say that if flying after diving is a problem, it is because of PPP.

When we dove in Clear Lake, Oregon at 3500 feet altitude, but would need to drive home over the pass at 5500 feet, we used the 5500 foot altitude for our dive planning,

When in the USAF for dives at San Nicholas Island, I pulled the divers to the surface at 12 hours before our planned takeoff time home on a HC-130 aircraft.

Now, here's a question. If you need to dive prior to flying (within 12 hours), why cannot you program your computers or use the altitude dive tables as if you were diving at 10,000 feet? Commercial flights will always be pressurized below 10,000 feet, as above that number people need to be on oxygen. The same applies to light planes, which don't carry oxygen on board. These planes usually fly VFR (visual flight rules), and FAA rules may require that a VFR plane climb to avoid instrument rules when encountering weather. 'Just a thought.

By the way, Altamira above is correct; DCI is a delayed emergency which can usually be dealt with. But a ditching at sea usually is a fatal accident.

SeaRat

"Commercial flights will always be pressurized below 10,000 feet, as above that number people need to be on oxygen."

Once again, I will give all divers a bit more information that you might not know or think about to help you make wise choices with regard to dive/fly guidance. It is true that commercial/military aircraft usually maintain a cabin altitude around 8000ft, unless the aircraft's cabin pressurization system fails, which is more common than you would like to think. If the aircraft experiences a rapid decompression (an emergency procedure that is routinely practiced by airline and military pilots in simulator training and evaluations), the aircraft cabin altitude can go from @8000ft to whatever altitude the aircraft is at at the time of cabin failure in less than a second or two. Per emergency procedures, the pilots will attempt to descend quickly and safely to an altitude below 10,000ft if possible. However, there are situations such as flying over high mountainous terrain where you might not be able to descend below a minimum safe altitude which could be well above 10,000ft. So if you are a diver on an airplane in that situation, and you chose to ignore dive/fly guidance, you are likely going to be royally screwed. Too often people make wrong decisions because they lack information. I imagine many SB readers are tired of this thread, but if this information helps one diver make a better decision, it will have been worth my time.

 

[John C. Ratliff]

How about just doing surface snorkeling in the 24 hours prior to flying. That should fix the problem, and at the same time give some good exercise and sightseeing. Like I said, any decompression issues with flying is due to PPP.

SeaRat

 

[Bob DBF]

If the aircraft experiences a rapid decompression (an emergency procedure that is routinely practiced by airline and military pilots in simulator training and evaluations), the aircraft cabin altitude can go from @8000ft to whatever altitude the aircraft is at at the time of cabin failure in less than a second or two.

And that's why I quit diving closer 48 hours before getting on a commercial airliner. I'm not sure it would be safe if the cabin lost pressure during the flight after I'd been diving for a week, but the advice is 24 hours.


Bob

 

[lerpy]

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?

As a pilot I would absolutely agree with Alamira's reasoning. On a twin if I lost an engine and am now operating on one engine I would want to put as much sky between me and the ocean. In the event of a second engine failure I would want as much glide time as I can possibly. If still running with one engine I would not be planning to ditch at that point. I would be planning to find a close runway to put down, and in the meantime building in as much safety as possible. Ditching into the ocean despite what the movies might indicate is more often than not unsuccessful.