CRJ air cond w/huffer cart?

[Palomino]

as I sweated in an APU-inop CRJ this morning it got me thinking...

...can you run an air conditioning pack with the airstart
(huffer) cart as the pneumatic source? We can do that on the 737 and I seem to remember the ERJ also capable of that setup.

Thoughts/input?

Thanks

 

[wmuflyguy]

yes you can

 

[Oakum_Boy]

You can, but it depends on the airline. At my company we can't because this one time, when a huffer went to 'low' the packs burned up I guess due to less than adequate bearing lubrication or something.

 

[MusicMan]

It will run the packs, but more often than not, the cabin will fill with fumes.

 

[Soverytired]

It will run the packs, but more often than not, the cabin will fill with fumes.

Yep. And when you finally apply take-off power, the ducts purge into the cabin and it smells like something is burning, big time.

(so I've heard)

 

[sweptback]

I've done it several times before ASA said not to do it any more. You just need to make sure the huffer is on high and not idle. If it's idling then you'll get the fumes.

 

[Kream926]

why not just get an air cart? or is this just a hypothetical question?

 

[kf4amu]

Theres a sign in the CLT ops crew room that says not to do that. So apparently its possible but not allowed at some airlines.

 

[yournextFO]

Depends on the huffer. Some do it quite well, others overheat after a couple of minutes. Generally speaking, at one regional carrier based in southeast, the huffers are not maintained nearly well enough to run the packs reliably.

As for why...well, often an air-cart is unavailable or does not work very well.

 

[Hovernut]

Never had a problem, except for clueless rampers who don't know how to run the thing!

 

[Gulf-front]

If you really want to try something fun, run the packs off the bottle! Yah 45 min. to recharge.


....and no it was not me.

 

[ACL65PILOT]

DCI is getting air in ATL. Heard that before, but it actually looks like they are doing it.
On top of that they are extending the hoses on A and B concourses to get to the back of the 700.

 

[N1VIBS]

why not just get an air cart? or is this just a hypothetical question?

At ASA, air carts are hypothetical!!

 

[MusicMan]

I've done it several times before ASA said not to do it any more. You just need to make sure the huffer is on high and not idle. If it's idling then you'll get the fumes.

Then you get to hear that thing whining the whole time you're sitting at the gate. I'd rather be warm or start #2 to get some airflow.

 

[sweptback]

Then you get to hear that thing whining the whole time you're sitting at the gate. I'd rather be warm or start #2 to get some airflow.

Listening to the engine whine is much quieter? Plus huffer carts don't burn 400 lbs/hr.

 

[wmuflyguy]

Listening to the engine whine is much quieter? Plus huffer carts don't burn 400 lbs/hr.

Plus the 50 seater engine at idle will not cool down the cabin at all.

 

[Palomino]

Then you get to hear that thing whining the whole time you're sitting at the gate. I'd rather be warm or start #2 to get some airflow.

i think the planeload of business-types in their suits would object to this theory.

this was an 80 degree day also. if it was an August summer day i'm sure a mutiny would've ensued.

it can be a challenge to get rampers to spool up the huffer in order to operate the packs. it is a loud machine at engine start settings, but it's an airport - they are loud by nature. as mentioned, i'd rather have the huffer blowing the packs than a gas-gulping jet engine at a relatively high fuel flow rate.

thanks to all for the feedback on the topic. just trying to keep cool on the commute and improve the company product.

 

[Palomino]

Plus the 50 seater engine at idle will not cool down the cabin at all.

definitely. this particular CRJ had no airflow from the overhead vents until the engines were spooled well above taxi settings. i think there were several factors in play and perhaps a majority of the air cond system was MEL'd.

hopefully it was fixed soon. the only time i've refused a plane was due to oppressively uncomfortable air condtioning. sometimes that's what it takes to get the rig fixed.

 

[CA1900]

Plus the 50 seater engine at idle will not cool down the cabin at all.

Who said anything about idle?

 

[BLing]

This exact topic came up today in training. Straight from the Bombardier man himself, he said not to do this as it is too much pressure for the packs to handle. He also said it smells like dirty a$$!

 

[Papa Woody]

Yep. And when you finally apply take-off power, the ducts purge into the cabin and it smells like something is burning, big time.

(so I've heard)

Clapped-out air-start machines like the ones typically inherited by the "regionals" have seals from about 1972 which seal......um......nothing.

Thus, the combustion fumes make their way from the pistons all the way thru the crankcase seals into the compressor where they infuse the pack air with the concentrated aroma of an oily diesel clanker.

 

[yournextFO]

This exact topic came up today in training. Straight from the Bombardier man himself, he said not to do this as it is too much pressure for the packs to handle. He also said it smells like dirty a$$!

Too much pressure? The engines on a CRJ200 at take-off power produce over 100 psi on the 10th stage, which is far more than any huffer I've ever seen. It's also why the packs have Pressure Regulating Shut-Off Valves (PRSOV's) which maintain about 30 psi normally.

I'd agree using a bottle to run the packs smells bad, but I've never had a problem with a huffer unless it was poorly maintained.

Tell your Bombardier man to try again.

 

[Papa Woody]

but I've never had a problem with a huffer unless it was poorly maintained.

I've never had a huffer that was maintained!

 

[91100 100 set]

If you really want to try something fun, run the packs off the bottle! Yah 45 min. to recharge.


....and no it was not me.

I know a guy who did that once.

 

[Rally]

What bottle are you guys talking about? Oxygen bottles/fire surpression bottles? (not that I think that) Just a little confused.

 

[CA1900]

What bottle are you guys talking about?

Air start bottles. A big air tank on wheels, used to air-start the engines when the APU is inop. It uses a smaller air compressor that wouldn't be strong enough to start the engines on its own, but is used to charge up the big air bottle, which is used for engine start. Then it has to be recharged, which takes a while...

 

[Rally]

Air start bottles. A big air tank on wheels, used to air-start the engines when the APU is inop. It uses a smaller air compressor that wouldn't be strong enough to start the engines on its own, but is used to charge up the big air bottle, which is used for engine start. Then it has to be recharged, which takes a while...

Ok what happens if they have a double and its not recharged? Thats crazy

 

[CA1900]

Ok what happens if they have a double and its not recharged?

Somebody's probably going to be delayed, but not by 45 minutes, especially if it's a small airplane. An RJ isn't going to deplete the whole air charge.

The odds of a small outstation handling two planes with inoperative APUs at the same time are pretty slim anyway. And a bigger station/hub will have multiple air bottles, a huffer cart (which has a much more powerful compressor that can supply that air continuously), or both.

Thats crazy

No, that's balancing cost versus benefit. (Same reason I don't drive an Excursion around, just in case I might want to buy a boat some day.) A huffer cart is a lot more expensive than an air bottle.

 

[shamrock]

Ok what happens if they have a double and its not recharged? Thats crazy

You get one plane started up then hook a hose up between the two to "jumpstart" the second plane.

 

[Stifler's Mom]

You get one plane started up then hook a hose up between the two to "jumpstart" the second plane.

I'd forgotten about that option. Has anybody actually done this yet.

Too bad the RJ doesn't have a hood on the nose that you can prop up just for asthetics.