Air cart usage.
Posted: Sun Feb 18, 2018 2:27 pm
I want to talk about when to use the external air cart. I see streamers using this to run a pack on the Flight Factor 757 and 767 as well as the FlyJsim 737, 727 and other aircraft with this option when they have an operating APU. If you have an operating APU and the bleed switch is not on MEL (Minimum Equipment List), there is never a reason to use the external HIGH pressure air cart.
There are two types of air we connect to our aircraft at the gate. There is conditioned air that usually plugs in from the yellow hose you see from the jetway, or could be a portable unit. This is NOT high pressure air! You do NOT use this to run a pack and could never be used to start an engine. This air comes from an air conditioning unit directly to the main supply duct into the aircraft, just like it comes from your vent at home.
The second type of air we can use is the HIGH pressure air from the cart you see as an option on the aircraft I mentioned. This is used when you have an APU, or APU bleed on MEL. We need a high pressure air source to start an engine and with out the APU we need this cart to start. This cart has a narrow high pressure hose. If you have ever been on a flight without an APU you have heard it’s high pitch noise and watched it belching smoke as your flight starts an engine at the gate. Technically you could run a pack with this but the air is not conditioned and could add an oder to the cabin. It is only a last option to use this for a pack.
So we use this air cart to start an engine at the gate when we can’t use the APU. I have noticed most of the sim system manuals discuss this procedure in the supplemental section.. Basically you stay connected to external AC power at the gate. Start the engine on the opposite side the cart is connected. After the engine is started connect the generator and disconnect ground power. Push back and on taxing out you do a cross bleed start. You use air pressure from the operating engine to start the second engine. On the 737 you have to run the power up quite a bit to get the minimum 30psi. Make sure you let ground know so you don’t flip the C172 over taxiing behind you. That’s all I have for now. Cheers,
Jim
There are two types of air we connect to our aircraft at the gate. There is conditioned air that usually plugs in from the yellow hose you see from the jetway, or could be a portable unit. This is NOT high pressure air! You do NOT use this to run a pack and could never be used to start an engine. This air comes from an air conditioning unit directly to the main supply duct into the aircraft, just like it comes from your vent at home.
The second type of air we can use is the HIGH pressure air from the cart you see as an option on the aircraft I mentioned. This is used when you have an APU, or APU bleed on MEL. We need a high pressure air source to start an engine and with out the APU we need this cart to start. This cart has a narrow high pressure hose. If you have ever been on a flight without an APU you have heard it’s high pitch noise and watched it belching smoke as your flight starts an engine at the gate. Technically you could run a pack with this but the air is not conditioned and could add an oder to the cabin. It is only a last option to use this for a pack.
So we use this air cart to start an engine at the gate when we can’t use the APU. I have noticed most of the sim system manuals discuss this procedure in the supplemental section.. Basically you stay connected to external AC power at the gate. Start the engine on the opposite side the cart is connected. After the engine is started connect the generator and disconnect ground power. Push back and on taxing out you do a cross bleed start. You use air pressure from the operating engine to start the second engine. On the 737 you have to run the power up quite a bit to get the minimum 30psi. Make sure you let ground know so you don’t flip the C172 over taxiing behind you. That’s all I have for now. Cheers,
Jim