The fact that this question pops up all the time belies the terrible design of the system.

Really or is it that folks don't read the manual? Maybe this is also a further example of why there are type ratings. :biggrin:I believe a better metric for your supposition would be how often pilots miss this during their type rating training.

Edited February 23, 201214 yr by falcon999

Really or is it that folks don't read the manual? Maybe this is also a further example of why there are type ratings. :(

I will only say Helios....A different warning, and/or a light at 10000ft and all could be different, without 100+ dead people.Humans are humans, but the system is not Murphy proof.

Now I think back.... I forgot to put the packs back on!!! Silly Silly SILLY Mistake!! :(

Davier, I hear what you say, and agree that is only a game, but still hehe. I and other RL pilots use this also as a practice place, but for then "for the fun" of it, do as in real life and deal with the problems hehe. Well it's up to the individual person to decide, hehe. Thanks for the healthy discussion. ;-)

had my throttle cracked open minutely horn sounded as soon as I turned battery on it drove me nuts till Ifigured it was that

The fact that this question pops up all the time belies the terrible design of the system.

 

Not true at all...the design of the 737 pressurization system is well proven...if fact, it came from the 727 design which was very well proven...in the final analysis, you'll find it usually is human error that caused the pressurization problem in the first place.

 

As for operating the pressurization system manually, the airlines (or most of them anyway) won't dispatch a passenger-carrying aircraft that has to have its pressurization system operated manually. The workload is so high, you can forget about the F/O being of any help to the Capt...it will take his full and constant attention to operate the out flow valve.

 

I know the person who posted switching to manual operation meant that if you're already in flight and lost auto and semi, your only fall back is manual, and this is true, but what a pain to finish the flight that way.

 

Airlines (again most) will only ferry an aircraft to a repair facility if it is at a location where it cannot be repaired and if they do, they will try to dispatch it as an un-pressurized flight.

 

To put it mildly, flying a trip with only manual pressurization is an extreme pain in the butt.

Hearing "Takeoff configuration alarm" in flight above 10,000ft =

 

Step 1: Put on Oxygen mask

Step 2: Stop any climb NOW (press ALT button on MCP)

Step 3: Figure out if it's a pressurization problem, or if you just forgot to turn the packs back on.

Step 4: If you forgot to turn packs on, turn them on now, If not, Try to control pressure in Manual mode, If you cannot stop the cabin altitude increasing, it's time to go down NOW - then tell ATC.

 

(if step 3 is "Just forgot to turn on packs" then do Step 3A: Call the Flight attendant, and ask if the masks have deployed in the cabin. If you managed to do step 2 through 4 quick enough, you might be in luck. If not, it's probably a good idea to divert somewhere because with all the masks dangling from the ceiling, the passengers already know something's up. - Generally if the in cabin altitude is above 14,000ft, the masks would have auto-deployed.)

 

Step 3B: Tell ATC you are either Resuming climb, or diverting, depending on the outcome of step 3 or 3A.

 

Step 0 - Wouldn't it be nice if they designed a pressurization alarm that had an electronic or recorded voice that said "Cabin Pressure" over and over.... like in the Embraiers.

As with any abnormal or emergency situation, the Capt should call for the appropriate check list, in this case, the Cabin Altitude Warning checklist (to start with).

 

The QRH section 2.1 states that the CABIN ALTITUDE light (if equipped) will illuminate. If not, the crew should know that this horn sounds for one condition on the ground and for one condition in the air...so they should not be wondering what's going on.

 

Interesting to note that the CABIN ALTITUDE light illuminating checklist does not take the crew through checking if the packs are on or not. The AUTO FAIL amber light procedure is the one that does that.

 

For those planes not equipped with the optional CABIN ALTITUDE light, the aural warnings on the 727 and 737 aren't so bad. On the L-1011 that I flew, it had (if memory serves me) no less than 13 different in-flight aural warnings and we were required to know each one by sound. When the flight engineer tested all of these sounds before flight, the cockpit sounded like a zoo!

 

The DC-10 was similar.

 

 

Not true at all...the design of the 737 pressurization system is well proven...if fact, it came from the 727 design which was very well proven...in the final analysis, you'll find it usually is human error that caused the pressurization problem in the first place.

Oh, it's a great pressurization system. It's the warning system that is rotten. The very fact that every day and every crew change I'm supposed to brief the AD is proof enough. Add some poor souls to that, and you've got evidence enough for everyone but the people who pay the bills.

 

The fact that a finding of probable cause is human error doesn't mean that a system isn't crap. It just means that a crappy system wasn't followed per the instructions.

 

Best book I've read in a long time has changed how I look at human error:

 

http://www.amazon.com/The-Limits-Expertise-Rethinking-Operations/dp/0754649644

>The very fact that every day and every crew change I'm supposed to brief the AD is proof enough.

 

So, you are a mechanic on the 737?

 

And what/who is the "AD"?

 

So, everyday you have to brief the AD about the pressurization system? What model 737? Just curious.

AD

 

>The very fact that every day and every crew change I'm supposed to brief the AD is proof enough.

 

So, you are a mechanic on the 737?

 

And what/who is the "AD"?

 

So, everyday you have to brief the AD about the pressurization system? What model 737? Just curious.

AD 2008-23-07 Airworthiness Directive from the FAA. I fly 737CL and NG, but it probably pertains to the -200, too.

 

Yes, you have to brief the how crappy the system is every day you fly. "If the intermittent warning horn blah blah blah, immediately don the oxygen mask blah blah blah."

 

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/9da618efecdae41c862574fd0050510b/$FILE/2008-23-07.pdf

 

 

(if step 3 is "Just forgot to turn on packs" then do Step 3A: Call the Flight attendant, and ask if the masks have deployed in the cabin. If you managed to do step 2 through 4 quick enough, you might be in luck. If not, it's probably a good idea to divert somewhere because with all the masks dangling from the ceiling, the passengers already know something's up. - Generally if the in cabin altitude is above 14,000ft, the masks would have auto-deployed.)

 

IIRC there is a warning light if the masks go down, so you should know. I agree that it is a better idea to divert even if the pressurization was reinstated. No good flying on with a bunch of extremely nervous people back there. AND you risk that in the case of actual depressurization further on, you don't have cabin oxygen available anymore. Better go on and land somewhere where the masks can be restowed and oxygen generators refilled (or however the chemicals are put back in)

 

 

 

So, you are a mechanic on the 737?

 

Matt here is our resident 737 pilot with a major US operator. Not sure if captain or F/O, but he is on the line.

 

 

Matt here is our resident 737 pilot with a major US operator. Not sure if captain or F/O, but he is on the line.

FO. And I prefer resident lurker.