AngelAirways
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Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 10:42 am

I recently had a thought and realised that many turboprops such as Dash 8s and ATRs, albeit pressurised, do not have cabin oxygen masks for pax.

I tried to search FAA certification requirements and also had a look at some airline safety cards - none of the turboprop operators had oxygen mask instructions on their safety cards.

I am also aware the Q400 can cruise up to 25,000 feet and yet it is not clear if they are fitted with O2 drop-down masks.

Does anyone know above what altitude it is mandatory to have individual passenger oxygen supply for certification requirements?
 
Pihero
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 11:29 am

Actually, you've already provided your own answer :
For aircraft operating under "Part 91", there is no need for O2 if the aircraft flies below FL 250.
The reason is that these aircraft have demonstrated that, in the case of a depressurisation, they could reach very quickly an altitude below 10,000 ft where the air is officially breathabl;e.
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AngelAirways
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 11:46 am

Thanks. but do you know if the same rule applies to Part 135 (commercial ops)?
 
Goldenshield
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 11:47 am

Quoting Pihero (Reply 1):
they could reach very quickly an altitude below 10,000 ft where the air is officially breathabl;e.

Or at minimum, a descent to 14,000, as that's the point where every occupant MUST have oxygen.
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DiamondFlyer
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 1:33 pm

Actually, I don't think passengers need oxygen until 15,000. Crew requirments start at 14,000 or more than 30 minutes above 12,500, cabin altitude. In reality, people probably need it lower than 12,500. I spent about 20 minutes at 12,000 in a Diamond 40, and can say I could feel that I needed oxygen.

-DiamondFlyer
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Markhkg
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 5:23 pm

§ 135.157

(b) Pressurized aircraft. No person may operate a pressurized aircraft—

(1) At altitudes above 25,000 feet MSL, unless at least a 10-minute supply of supplemental oxygen is available for each occupant of the aircraft, other than the pilots, for use when a descent is necessary due to loss of cabin pressurization; and

(2) Unless it is equipped with enough oxygen dispensers and oxygen to comply with paragraph (a) of this section whenever the cabin pressure altitude exceeds 10,000 feet MSL and, if the cabin pressurization fails, to comply with §135.89 (a) or to provide a 2-hour supply for each pilot, whichever is greater, and to supply when flying—

(i) At altitudes above 10,000 feet through 15,000 feet MSL, oxygen to at least 10 percent of the occupants of the aircraft, other than the pilots, for that part of the flight at those altitudes that is of more than 30 minutes duration; and

(ii) Above 15,000 feet MSL, oxygen to each occupant of the aircraft, other than the pilots, for one hour unless, at all times during flight above that altitude, the aircraft can safely descend to 15,000 feet MSL within four minutes, in which case only a 30-minute supply is required.
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KELPkid
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 5:46 pm

Quoting DiamondFlyer (Reply 4):
Actually, I don't think passengers need oxygen until 15,000. Crew requirments start at 14,000 or more than 30 minutes above 12,500, cabin altitude. In reality, people probably need it lower than 12,500. I spent about 20 minutes at 12,000 in a Diamond 40, and can say I could feel that I needed oxygen.

-DiamondFlyer

I've hiked a 13,000 foot high mountain pass before...you don't need supplemental oxygen to do that   It was a 6 day wilderness hike though...your body makes the transition pretty easily when you are ascending at a walking pace over normal to slightly steep grades.
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DiamondFlyer
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Fri Nov 05, 2010 7:13 pm

Quoting KELPkid (Reply 6):
I've hiked a 13,000 foot high mountain pass before...you don't need supplemental oxygen to do that   It was a 6 day wilderness hike though...your body makes the transition pretty easily when you are ascending at a walking pace over normal to slightly steep grades.

IMC in moderate rain in a light piston, at about 36 degrees. I had been cruising at 10,000, and went up to 12,000 to see if I could get on top. I will say I did feel a difference between 10 and 12K, and as such, went back down to 10,000 once I found out I wasn't getting on top. But once you get that high in a naturally aspirated piston, there isn't a whole lot of climb left, so it wasn't worth carrying oxygen. Did I need the oxygen, probably not. Would I have felt much better with it, for sure.

-DiamondFlyer
From my cold, dead hands
 
KELPkid
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Sat Nov 06, 2010 5:13 am

Quoting DiamondFlyer (Reply 7):
IMC in moderate rain in a light piston, at about 36 degrees. I had been cruising at 10,000, and went up to 12,000 to see if I could get on top. I will say I did feel a difference between 10 and 12K, and as such, went back down to 10,000 once I found out I wasn't getting on top. But once you get that high in a naturally aspirated piston, there isn't a whole lot of climb left, so it wasn't worth carrying oxygen. Did I need the oxygen, probably not. Would I have felt much better with it, for sure.

I have also cruised at 12,500' in a Centurion (no poop left at all in the naturally aspirated engine at that altitude!). Never felt anything related to hypoxia...I flew with the owner of the same Centurion once, IFR down in Mexico, where the MEA on the airway was 15,000 (we were on O2). Fortunately, it was at night, otherwise I don't think we could have made our altitude...  
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rwessel
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Sat Nov 06, 2010 6:51 am

Quoting KELPkid (Reply 6):
I've hiked a 13,000 foot high mountain pass before...you don't need supplemental oxygen to do that It was a 6 day wilderness hike though...your body makes the transition pretty easily when you are ascending at a walking pace over normal to slightly steep grades.

Or you can ski Breckenridge. At least then you can ride the lift most of the way up!  
 
thegeek
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RE: Above What Altitude Is Cabin Oxygen Mandatory?

Sat Nov 06, 2010 7:15 am

If oxygen only needs to last for the listed times, wouldn't the extra fuel needing to be carried on certain LROPS (or whatever the new ETOPS is called for you) to proceed for 179 minutes or more at FL100 be quite substantial? I'm thinking of these flights in particular:
SYD-JNB
SYD/MEL/BNE/AKL/NAN towards LAX/SFO/YVR
LAX/SFO/SAN/SEA-Hawaii
SCL-IPC
GRU-JNB

Probably a lot of ones I haven't thought of.

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