Nick
Well-Known Member
Five legs a day with an APU could get old after enough times!
Why are APU's INOP so often?
- Thread starter Andrew_VT
- Start date
Five legs a day with an APU could get old after enough times!
Baronman
Well-Known Member
5 legs do suck any way you cut it, true...And yeah I know it sucks being in an AC without an APU. If it means anything our avionics/screens put off heat like a hot plate, it's like a sauna w/o air.
Fly4Pay
New Member
Along the lines of the "heat" answer.... the engines get a nice, relatively constant flow of cool air coming in the front, and they rarely run at full power. APUs are usually operated at a standstill (less airflow), and they run all out when on.
Lotsa stress there, seems to me...
Lotsa stress there, seems to me...
Andrew_VT
Well-Known Member
Timbuff10
Well-Known Member
For you guys calling it a "huffer cart", correct me if I am wrong but shouldn't we call it a "Puffer cart" instead?
The last time I hooked one up to a 737, the tube that goes from the cart to the plane busted and the whole thing exploded into a million pieces all over the place.
The airstart cart just blows out a fast rush of air into the engine to get the number 2 engine started whereas if the APU were functioning it would be able to do this on the No1 engine and then use that power to start the No2?
The last time I hooked one up to a 737, the tube that goes from the cart to the plane busted and the whole thing exploded into a million pieces all over the place.
The airstart cart just blows out a fast rush of air into the engine to get the number 2 engine started whereas if the APU were functioning it would be able to do this on the No1 engine and then use that power to start the No2?
Nick
Well-Known Member
Yes, but, at least in the ERJ (and from jumpseating, all others too) the APU can start either engine first.
Timbuff10
Well-Known Member
Now that you mention that, I think the reason why I thought the APU could only start No1 first was because we usually had ground crews still roaming around on the starboard side of the aircraft. No2 only started after we disconnected and showed them the bypass pin with a salute.
APUs are nice!
BobDDuck
Island Bus Driver
On the CRJ 200 (as somebody already said) the problem normally stems from the door. There are 3 positions and 25 parts. If any one of those stops working or reads incorrectly, the whole process stops. They fixed the problem on the 700 with only 2 positions and 3 parts.
kellwolf
Piece of Trash
About the same here. I think I've only had about 4 deferred APUs since I've been here. Taking them to a station that doesn't have an air start is a pain, though. Then you've got the "hot refuel" going on. I had one the other day that the APU worked, but the APU generator was deferred. So, we had bleed air, but no AC power from the gen. I'd take that over a deferred APU any day, though. Air starts and cross bleed starts pretty much do nothing be take up time and manpower.
If it's the door, a lot of the time they can just defer that and wire the door open. Then, you've got the APU, but you either have to run it the whole time or keep it under 300 kts in cruise. If you see "APU door deferred closed," your APU is toast and so are your passengers in the summer in MEM.
Highney, there's a circuit breaker to reset the ECU....but....uh....I wouldn't know much about that since....it's....uh.....a MX function.
Bandit_Driver
Gold Member
You are correct. I think purdue has one of them. The APU in the Saab is nearly useless as it is too small. It can only run 1 pack and charge the batteries. If you try to start off of it, it will die. It is also a huge weight penality in the aft cargo hold.
In the Saab you are better off just getting number 2 turning as quick as possible. But you will have the ground handlers complaining because it is loud in the cargo hold and if the wind is right they are sucking exhaust.
ERfly
Well-Known Member
It all depends on where you place the huffer cart. I know at CAL, they start #1 off the huffer cart because of where they place it...then they start #2 using a cross-bleed start somewhere down the line.
On the ERJ (at least at XJT), we start #2 off the huffer cart for 2 reasons. The connection piping goes directly to the #2 engine and not through the cross-bleed. We get more air that way. Also, the nosewheel steering is on the #1 hydraulic system. We don't want that to engage accidentally, so we don't start that one until the tow bar is off. You can start both off the huffer cart. However, the start on #1 will take a little longer and be a little warmer.
