CRJ-200 Pack Question

[CRJ puppy]

How about something to do with the right pack distributing 70% to the cabin, 30% to the cockpit (L pack is the opposite)

EXACTLY!

 

[Bluto]

To run the packs off external air you need the noisy type high pressure air cart and I don't think anyone normally does this.

I do this with a deferred APU and a hot, sticky, nasty airplane sitting on the ramp. But yeah, usually, not.

 

[Inconceivable]

For those who fly the CRJ-200:

You are probably aware that when:

Low Pressure Air Cart + Right Pack Engaged = Higher Airflow through the flight deck gaspers

The higher airflow happens ONLY when the right pack is engage, ie. the left pack is off. It does not matter if the APU is on or off, and the position of the load control valve / isolation valve does not affect the results. Pack pressure reads zero during this condition.

Anyone know exactly what is happening to cause the higher airflow?

Fluid flow.

The LP air connects directly to the Distribution Manifold, which is downstream of the packs. Despite the "simplified block diagram" in the manufacturer's FCOM, the crossflow manifold is of a smaller diameter to than the manifold to the cabin. This difference is what directs 70% of mass air flow to it's respective side. When the right pack is engaged by itself, it has a nominal output of 45 psi--directing the mass flow equivalent of 30psi to the cabin (normal) and the mass flow equivalent of ~15 psi to the flight compartment. By flowing through the narrower distribution manifold, pressure increases.

When the air from the external cart joins in the crossflow manifold, it "goes with the flow" increases the pressure and mass airflow to the flight deck.

 

[Flyer1015]

I'm just surprised this was a real, legit, pack question for the CRJ (and not some thread about a back pack on the CRJ).

 

[SSDD]

Its a legit question, but a little disturbing. The original poster thought he could run the packs on LP air! It took 11 posts for someone to see the problem.

 

[TurboAWD]

No, he didn't think that.

Turbo

 

[Edge540]

Its a legit question, but a little disturbing. The original poster thought he could run the packs on LP air! It took 11 posts for someone to see the problem.

No, your misunderstanding is disturbing

You cannot "run" a pack off low pressure air. Re-read my posts, I specifically stated that the pack pressure indicated ZERO. I am simply selecting the pack to the on position to get the increased airflow.

Inconceivable, thanks for your effort in producing the best answer so far.

 

[PeanuckleCRJ]

Fluid flow.

The LP air connects directly to the Distribution Manifold, which is downstream of the packs. Despite the "simplified block diagram" in the manufacturer's FCOM, the crossflow manifold is of a smaller diameter to than the manifold to the cabin. This difference is what directs 70% of mass air flow to it's respective side. When the right pack is engaged by itself, it has a nominal output of 45 psi--directing the mass flow equivalent of 30psi to the cabin (normal) and the mass flow equivalent of ~15 psi to the flight compartment. By flowing through the narrower distribution manifold, pressure increases.

When the air from the external cart joins in the crossflow manifold, it "goes with the flow" increases the pressure and mass airflow to the flight deck.

Excellent post... I remember at Pineapple, it was the ultimate sin to engage the R pack when low pressure was connected- it was unapproved and could damage the airplane and cause terrorist attacks.

Apparently, engaging the pack is "the" procedure now, haha.

I love the morons that they have in flight standards there...