"no fly" time

[netdiver]

Greetings.

I'll be in the Hawaiian archipelago for 2 weeks in April. The trip will start on Oahu, them jump to Molokai, and then the Big Island. My question concerns the "no fly" period of 24 hours after a multi-day dive. What altitude is considered a "flight"?

The island hopper planes in Hawaii only travel between 60-120 miles. So it would seem to this casual observer that they don't obtain a very high flight altitude. My hopes, therefore, would be that I would not need to place much concern with these flights that are 18 hours after my last multi-day dive.

Is there an official altitude and/or duration that define a "flight"? Should I be concerned about these flights after my multi-day dive plan

 

[jimdiverman]

Greetings.

I'll be in the Hawaiian archipelago for 2 weeks in April. The trip will start on Oahu, them jump to Molokai, and then the Big Island. My question concerns the "no fly" period of 24 hours after a multi-day dive. What altitude is considered a "flight"?

The island hopper planes in Hawaii only travel between 60-120 miles. So it would seem to this casual observer that they don't obtain a very high flight altitude. My hopes, therefore, would be that I would not need to place much concern with these flights that are 18 hours after my last multi-day dive.

Is there an official altitude and/or duration that define a "flight"? Should I be concerned about these flights after my multi-day dive plan

As I understand it, even commercial airliners that fly to 40000 feet only compress the cabin to 8000 feet. You are taking a risk flying on any plane within 24 hours. This rule may be on the conservative side, but keep in mind that if you want DAN to cover you, you can't expect them to cover you if you break the rules, any of them.

 

[diversteve]

Don't go to the Volcanoes National Park on the big island right after diving either.

Kilauea is over 4000' tall.

 

[UWSojourner]

The risk depends on what type of diving you do. I just departed Hawaii and did a number of shore dives that were no deeper than 40ft. What are your dive plans?

 

[lowwall]

And what rule would that be? Since 2002, DAN's recommendation has been:

* A Single No-Decompression Dive: A minimum preflight surface interval of 12 hours is suggested.
* Multiple Dives per Day or Multiple Days of Diving: A minimum preflight surface interval of 18 hours is suggested.

 

[jimdiverman]

And what rule would that be? Since 2002, DAN's recommendation has been:

So the OP said they are making multiple days of diving, so by your DAN quotation, the rule is 18 hours SI after diving.

 

[Damselfish]

The island hopper planes in Hawaii only travel between 60-120 miles. So it would seem to this casual observer that they don't obtain a very high flight altitude.

I was curious what altitude they get to, so I pulled up a random Hawaii flight in one of the flight trackers and found an Aloha flight from Honolulu to Kona - it's currently at 23000 feet.

 

[Bill_PNW_Diver]

No matter what the duration of your flight is you will still reach an unsafe altitude. To conserve fuel even short hops go over 20,000 feet in altitude and pressurize to about 8000 ft.

It's definitely not worth risking the chance you will spend several days and several thousand $$ in the chamber.

 

[GrimSleeper]

Going anywhere above 300m/1000ft without an adequate surface interval is risking DCS. Since you've given yourself 18 hours (as per DAN guidelines) between your last dive and your flight, you should be fine. Don't be tempted into thinking you can get away with a 'shallow' dive less than 18 hours before you fly, though: even diving to 30-40 feet might, in theory, leave you with enough of a nitrogen loading to cause a problem when you fly.

We regularly time customers' last dives on a trip so that they get an 18 hour surface interval before they head off on an unpressurised local flight, and have never had a problem. You're probably more at risk, as sjspeck pointed out, if you head off up a volcano after diving.

 

[lowwall]

You are taking a risk flying on any plane within 24 hours. This rule may be on the conservative side, but keep in mind that if you want DAN to cover you, you can't expect them to cover you if you break the rules, any of them.

According to DAN, he needs 18 hours. According to the OP, he's got 18 hours. Ergo - no rules are being broken.

You are correct that he will experience a cabin altitude of 8,000 feet on these inter-island flights, so the 18 hour rule is applicable.