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Originally Posted by mike734
(Post 1554407)
I know. Not intuitive but true. Here is the paragraph from the 737 Technical site that explains it.
"A single pack must work harder than two packs to cool the cabin to a given temperature. Hence the APU must supply higher bleed air pressures to assure proper environmental control system operation. This higher pressure requires a greater Inlet Guide Vane (IGV) open position than that required for 2–pack operation. Since there is less airflow required to operate 1–pack than is needed, a significant amount of unused bleed air is exhausted through the Surge Control Valve (SCV). This higher IGV open position and large quantity of unused air translates into higher APU fuel burn and higher EGTs during 1–pack operation. Also, the high airflow levels exhausting through the surge control valve increases the overall APU generated noise by 2dbA. With 2 packs supplying the cabin cooling requirements the pressure requirement is lower, resulting in lower turbine inlet temperatures, EGTs and far less unused air being discharged through the surge valve." Denny |
Originally Posted by mike734
(Post 1554407)
I know. Not intuitive but true. Here is the paragraph from the 737 Technical site that explains it.
"A single pack must work harder than two packs to cool the cabin to a given temperature. Hence the APU must supply higher bleed air pressures to assure proper environmental control system operation. This higher pressure requires a greater Inlet Guide Vane (IGV) open position than that required for 2–pack operation. Since there is less airflow required to operate 1–pack than is needed, a significant amount of unused bleed air is exhausted through the Surge Control Valve (SCV). This higher IGV open position and large quantity of unused air translates into higher APU fuel burn and higher EGTs during 1–pack operation. Also, the high airflow levels exhausting through the surge control valve increases the overall APU generated noise by 2dbA. With 2 packs supplying the cabin cooling requirements the pressure requirement is lower, resulting in lower turbine inlet temperatures, EGTs and far less unused air being discharged through the surge valve." |
Originally Posted by FlyBoyd
(Post 1554323)
The actual number is 200#. The rest is overage and is funneled to cover cost of Area 51.
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Originally Posted by lolwut
(Post 1554131)
Tool of the day: The pilot that turns it on when the FA asks, knowing the costs, system wear, and that it deviates from your standard procedures.
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Originally Posted by Denny Crane
(Post 1554406)
Uhhh, silly me..........just gonna ask, how does a one pack operation use more gas than two pack operation?
Denny |
Originally Posted by gloopy
(Post 1554398)
You'd be astonished at how many pilots just turn it on to shut them up.
So I do like 80: I lie, and run away. I go walk around in the fresh air. By the time I'm walking back to the front, the Captain has usually caved in. |
This one is probably way too Delta-specific: the guy at Allied Airbus that decides which vans are still road-worthy (all of them), and which need passable steering, shock-absorbers, and seatbelts (none of them).
They should at least give you an epidural kit, and a barf-bag when they pick you up... |
Originally Posted by FlyBoyd
(Post 1554323)
The actual number is 200#. The rest is overage and is funneled to cover cost of Area 51.
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Originally Posted by Dirtdiver
(Post 1554469)
Not always FAs. 1 hour+ to push, 40 degrees F outside, sun shining on him so he's a little warm. Cranks the APU. I shut it down, told him to crack his window.
So we're running $400+/hr coffee machines one day and the next day sweating out the cabin trying to wait til 5 prior. Its one of the few areas the $#!+ hot pilot cadre in this country could improve on. :cool: |
Originally Posted by Red Forman
(Post 1554233)
The only person that is impressed with you being a pilot is the hot girls boyfriend.
TOTD: Any of the amorous airmen and line boys who try to hit on Mrs. Cardiomd in the FBO lounge. On numerous occasion I have had to chase away pilots who are trying to chat her up in a not subtle way while ignoring me. She looks much younger than she is, but seriously, sometimes she is old enough to be some of these guys' mother. She also has a big ring on her finger. :mad: You would think that some of these dudes have never seen an actual woman before. I now carry a rolled-up Trade-A-Plane to swat any pilot who gets too close and thinks he has a chance. :rolleyes: |
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