msp727

I was recently on flight 4817 from LAX-LAS on 6/29 operated by Skywest. The flight left the gate with an inoperable APU unit. The aircraft was blazing hot inside due to the air conditioning unit not being able to be operated without a running APU or engine. As you all know the aprons at LAX in some areas don't allow engine start up until fully pushed back at the gate. Once the flight left the gate it stood in the apron with a failed nose gear, still no engines for 1.5 hours until the gear was fixed, it turned out to be an electronics issue.

Is it safe to operate a flight without a working APU? In the event of an engine flame out what type of power would operate the controls? It is my understanding that a flight can only be operated with an inoperative APU as long as there are no other electronics issues, which wouldn't seem to fit this case.

I am really beginning to question the safety of the Delta Connection carriers, more and more I am experiencing issues like this one. Are the connection carriers sacrificing safety to ensure they meet Delta operational contractional commitments?

Anyone else have experiences like these?

3Cforme

Yes. The other engine. Mainline ops, too, can be conducted without functioning APUs.

NittanyLion

Tangentially related --- but some of the turns I've seen on the regional jets at outstations (typically outstations for me are DAY, LEX, or SDF) are INCREDIBLY fast.

Never specifically timed one, but it seems like 10-15 minutes.

I know outstation turns are often only allocated 30 minutes --- but I hope they're not sacrificing safety in the interest of catching up on schedule.

airboss7777

APU INOP operations are not the normal when I flew at a Delta Connection Carrier.
They do happen. It is up to the captain if they want to accept the airplane in that instance. Operationally the company wants you to operate it. In the summer heat I would refuse any airplane in the CRJ-200 with an APU inop. As you know it can get too hot too quick. The CRJ-700 is a different story, and no big deal with an APU inop.

Is it safe to operate a flight without a working APU? YES, within reason (see above)

In the event of an engine flame out what type of power would operate the controls? The controls of the CRJ are hydraulically actuated. If you lose both engines, a mini generator (Ram Air Turbine) pops out to provide electrical power and basic hydraulics.

It is my understanding that a flight can only be operated with an inoperative APU as long as there are no other electronics issues, which wouldn't seem to fit this case.
Each scenario is different, and the pilots would have to reference the Minimum Equipment List.

gte157q

i've had this concern and asked the pilot on more than one occasion... response has always been that no APU is not a big deal on the CRJ, because in the case of a flamemout they would air-start anyway (let the wind going thru the engine start it) rather than use the APU to start. That leaves the APU only needed for power and hydros while the engine is out, and the RAT handles it. So nice to have on the ground (so you can start without a huffer cart) but not needed for safe OPS in the air.

DXjr

Your story makes no sense at all. With no APU, they would have needed to start an engine at the gate to keep power going on the aircraft. Otherwise, the plane would have been dark.

rylan

I just flew on an A320 the other day from MSP-BOS and there was no APU... pilot mentioned this and they had to start the mains at the gate with one of the external turbine air starters. Then we taxied, started the second engine while in line for takeoff and pilot came back on saying we have to go back to the gate due to a fault light after starting the other engine... apparently something confused the computer due to the air start and they had to shut down the engines and restart to fix it, but we didn't have an APU so had to go back and get 'jumped' again.

avidflyer

I believe it is called a cross-bleed start. The portable compressor is used to start an engine at the gate and that engine is used to start the 2'nd engine.

rylan

Yup, thats what they did with on my mainline flight.

DXjr

You'd be correct. And the compressor, at least in colloquial terms, is called an 'air start' or even 'the bottle.' However, sometimes, the air start will be used to start both engines, but that's at PIC discretion.

However, like I was trying to say at least, when away from the gate, the APU, or an engine would have to be running at all times to provide power and A/C (well, with what little can pumped out on the CRJ-200 here with only 1 engine running at idle.)

dilbertsdaddy

Air conditioning almost NEVER works on ASA 50 seater (2nd summer in a row)...some of it is probably APU related but I don't think every flight I have been on has an inop APU.

airboss7777

It's not a ASA problem, its a CRJ-200 problem.
Especially on short flights. Lets say the crew shows up 1 hr prior to departure.
Takes 30 mins to properly cool down. You board with 49 other pax. It gets hot again throughout taxi and until takeoff.
Fly for 1 hour, descending the plane gets hot again, and repeat the process.
Its an uphill battle on hot days with short hops.

BenA

I'm sometimes asked by regional F/As when leaving CRJ200 flights in the summer to lower the window shades, helping the aircraft stay cool while parked at the gate. On flights where I board and all the shades are down, it does seem to be noticeably better.

Would be nice if this became a widespread practice in the summer months...

Seth

ETOPS aircraft cannot fly ETOPS routes without a functioning APU. Some days I think DL would do ETOPS with a CRJ-200 if they would fit enough fuel tanks on it and find an engine that could get certified!