Diving before/after a ride in a small airplane (cessna style)

[alaxias]

I'm planning a trip to Vancouver and from there to Vancouver island it's a 2.5 hours boat ride. I'm considering taking a plane instead (I'll be staying in the city of Vancouver so I'd go to the island, dive, then come back to the continent).

Here's the type of planes, do the usual rules apply: Harbour Air : Welcome!

Thanks!

 

[windapp]

Planes normally only pressurize to 8000 ft. That means that the risk of dcs is the same whether you are going to 8000 feet or 30000 feet. Of course, flying before diving doesn't increase your risk from a pressure point of view.

 

[Tortuga68]

Planes normally only pressurize to 8000 ft. That means that the risk of dcs is the same whether you are going to 8000 feet or 30000 feet

Not if the plane depressurises...

However, the DHC-3 Otter shown in the link normally has an unpressurised cabin - so the question is do they exceed 8000 ft during the flight (I would guess not, but the operating ceiling for the aircraft is 18000 ft according to Google)

The flight over won't be an issue, but I would suggest following the normal rules regarding SI before the trip back - or, take the boat

 

[Damselfish]

However, the DHC-3 Otter shown in the link normally has an unpressurised cabin - so the question is do they exceed 8000 ft during the flight (I would guess not, but the operating ceiling for the aircraft is 18000 ft according to Google)

the question isn't whether they exceed 8000 ft, but 2000 ft - which is what folks like DAN define as going to altitude. 8000 ft just happens to be what commercial jets generally pressurize to but isn't any kind of magic number related to diving. The 2 things often seem to get muddled together.

 

[Thalassamania]

Having spent more that a few nights flying back at 500 feet, burning a lot of fuel, let me tell you the basic facts: Small planes are often not pressurized at all so flying in the requires that you conduct all dives for the previous day using altitude corrections equivalent to the highest altitude that the plane will go to (this if often not know) or after a 24 hour surface interval.

There are other approaches but those are the basics.

 

[alaxias]

Thanks, I guess we'll take the boat!

 

[bleeb]

It might be interesting to contact the airline and see what they say. Given the area, it's probably not the first time they've dealt with divers. The main issues to be looking for are what altitude they normally fly at, how high might they go if directed by ATC, and whether it's a big issue for the pilot to keep in mind there's an altitude-limited passenger in the back. If you do get any information from them, I think at least a few of us would be curious to hear the results.

Based on their responses, it might be possible to apply the NOAA Ascent to Altitude table to determine minimum surface interval requirements, depending on how definitive the answers from the operator are.

For everyone else reading this thread, these flights are over water, between airports or seabases at sea level. They're about 30-50 mi/50-80 km and roughly 30 minutes terminal to terminal, and since they're almost completely over water and with relatively little air traffic, there might not be a requirement to routinely fly all that high, just high enough (one or two thousand feet) to get out of the surface turbulence.

 

[windapp]

the question isn't whether they exceed 8000 ft, but 2000 ft - which is what folks like DAN define as going to altitude. 8000 ft just happens to be what commercial jets generally pressurize to but isn't any kind of magic number related to diving. The 2 things often seem to get muddled together.

My point was that it makes no difference what plane you are on, or how high they fly, the normal rules apply.

 

[Tortuga68]

It does make a difference

the question isn't whether they exceed 8000 ft, but 2000 ft - which is what folks like DAN define as going to altitude. 8000 ft just happens to be what commercial jets generally pressurize to but isn't any kind of magic number related to diving. The 2 things often seem to get muddled together.

I was referring to the Otter having an unpressurised cabin - if they exceed 8000 ft with an unpressurised cabin, then you should increase your SI before flying. If not then the 'normal' rules of flying (or ascending to altitude) would apply; as I mentioned in the bit of my post you didn't quote

 

[Thalassamania]

It does make a difference

I was referring to the Otter having an unpressurised cabin - if they exceed 8000 ft with an unpressurised cabin, then you should increase your SI before flying. If not then the 'normal' rules of flying (or ascending to altitude) would apply; as I mentioned in the bit of my post you didn't quote

The altitude of the flight has no effect on the "normal" rules (e.g., 24 hrs. before you fly). After a full day you are essentially clear of excess nitrogen and it really does not matter if you go to 8,000 or 12,000 or even higher (though you may need oxygen to maintain consciousness).