Crew oxygen min dispatch

[Riccardo]

Hi guys,

I'm doing a bit of research and trying to find out the crew oxy minimum dispatch requirements for some different types. If you'd be so kind as to tell me what type you are familiar with and min dispatch px I'd appreciate it greatly,

Cheers.

[potkettleblack]

For an A320 series then the information you require is in table format within FCOM 3.01.35 - Limitations. Depends on the number of people in the cockpit and the reference temperature (a calculated average between OAT and the cockpit temp).

[411A]

L1011, minimum FD crew oxy pressure, 950 psi.

[_FL600_]

For most Boeing aircraft, you'll find that info in FCOM 1, under performance dispatch.

It all depends on the volume of oxygen cylinder installed, number of pilots using O2 in flight deck and temperature. So, one figure for a specific airplane won't do you good really.

Happy trails

[Ocampo]

If I recall correctly, under my school SOP, minimum O2 requirements was 1000PSI for the PA-28 hehehe

[Love_joy]

Embraer 145 with my operator, we had a min despatch of 1100psi or 1500psi if we had a jumpseater.

Dash 8 Q400, same operator, is 1300psi min despatch, or 1800psi for 3 crew.

Presumably we work harder on the Q4!

[lalbak]

As per Fokker AOM and company SOP 1000psi for 2 crew, 1450psi for 3 crew in the Fokker 50.

[Gooneyone]

Dash8-300: 3 cockpit crew 1800psi, 2 cockpit crew 1300psi

[p51guy]

Just look it up in limitations. Why ask this question?

[spannersatcx]

A340 +10C 2 pilots min press 580psi

[renard]

RJ100 2crew min 1575psi, 3 crew min 1100psi.

But I'm not sure why psi is important. If made the storage container half the volume, the psi would double , or double the size of the tank and halve the psi, and you'd still have the same amount of O2.

The regulator in the system will reduce it to a pressure that you can breathe.

I don't know what quanitity of O2 tht pressure equates to, but our manual sayas that for a/c certified to fly at altitudes greater than 25000', in the event of a pressurisation failure, there must be suficient O2 for the entire flight, subject to a minimum of 2hrs.

[FE Hoppy]

2 hours oxygen for each crew member following the prescribed descent profile. This applies to all the types previously mentioned in this thread.

[Riccardo]

Thanks guys,

It's just a generalisation I'm looking for, I know there's a huge variation type to type but it seems generally nothing much below around 900psi...

I'm just trying to write a business case for a couple of airlines to install gas intensifiers to their oxygen carts - for example the outfit I am working for right now (B1 eng) has a minimum nightstop level of 1600psi, so we are sending our oxy bottles back for recharge when they are still more than half full, doesn't make sense. Just wondering how many other airlines do the same..........

[Storminnorm]

Most of the outfits that I worked for used to have their own
Oxygen charging rig to top up the system themselves.
Probably BANNED from doing that now. 'Elf & Safety!!!!
Bloody dangerous stuff that Oxygen.

[Riccardo]

That's what I'm talking about norm, we top up the bottles in situ from a ground rig, but the bottles on the ground are supplied at 3000psi. When ours drop to 1600 we send them off for a new one and put a full bottle into the cart. If we used an intensifier we could smoke the cart bottles down to 200psi and still get 1850 into the aircraft bottle.

[robertbartsch]

I thought there was a crash near Miami involving a discount carrier where half empty oxygen bottles blew on T/O.

[Riccardo]

No that one you're thinking of (I think) was where the shipping agent pulled the pins out of a shipment of oxygen generators before they were put in a box in the hold. The heat they produced brought the plane down.

ValuJet flt 592??

[muduckace]

Riccardo

Slight misinformation. The O2 generators were not labled as hasmat and it is thought that a un secured tyre was also in the cargo hold, suspecting a impact with the box of generators.

Also, it is not a matter of pulling the pins out of O2 generators but installing a shunting cap that grounds the 2 pins that activate them together preventing them from discharging from as small of a current as electro-static.

This is off topic.

[muduckace]

As stated above approx 1500 psi is normal dispach limits on the airframes I know. I believe it is calculated to provide 30 minutes of O2 to allow a descent to a breathable altitude. This pressure is of course calculated on the the demand of the quantity of persons the bottles supply.

[Riccardo]

Thanks Muduck, yeah I remembered off the top of my head it was oxy generators - couldn't remember the details, just wanted to point out it wasn't bottled oxy. And yes it's off topic, funny how that happens.....

Thanks all for the min dispatch info.