Why can't i select the spd button in the autopilot it doesn't seem to work

[Orlaam 328]

Mats, I've seen a few problems from FSUIPC, even some Pete Dawson himself didn't think could be an issue, but they were. As far as knowing all the system and how they relate to every part of the aircraft, I only know what I need to fly the thing and not a whole lot more. Maybe I shouldn't help.:-hmmm I wouldn't think you could be in the air without the generators on?

[Qavion 19]

>I wouldn't think you could be in the air without the generators on?Interesting question, Chris.To get into the air, you need thrust and flight controls. 737NG flight controls have manual backup, so you wouldn't even need hydraulics (but hydraulics should work anyway with the engines running... using the engine-driven pumps).So how do you start the engines...You need electrical power for the ignition system, electrical power to control the opening of the start valve and a source of bleed air. Fuel can be suction fed, so you don't necessarily need main bus power for fuel pumps.The engine ignition system can be powered by the Standby Bus (which is powered by the battery). The engine start valve is opened using 28Vdc power from the battery. The APU is a source of bleed air for the engine starters. The APU can be started using the battery. Here are a few things which might stop you...1. The Bleed Isolation Valve is powered by a main bus (generator required). However, if the valve was open from a previous flight, starting the Right Engine shouldn't be a problem.2. I'm not 100% sure if the APU Electronic Controller has full control over APU bleed air with only Battery power available. You need to open the APU Bleed Valve to get air to the engine starters and the APU needs to provide a lot of air for engine start. I'd could only guess it would be OK.Getting into the air with no generators sounds possible, but, of course, it wouldn't take long for the battery to go flat in these circumstances.Perhaps a real NG expert can comment on this? ;-)Cheers.Ian

[Mats_J 2]

Chris,Don't take my response to Joe the wrong way. My response to Joe was not meant as critique against you. But this problem and the symptoms point to a very common operating error and it's been around since the NG was released. Of course you should try to help others out if you think you know what is going on. ANd you will probably learn something along the way as well as I have done over the past months (or was it years?) ;-)I see Ian gave you a good essay about generators and flying so I'll skip that one! :+Cheers,

[Mats_J 2]

Ian,your statement below made me a bit confused>1. The Bleed Isolation Valve is powered by a main bus (generator >required). However, if the valve was open from a previous flight, >starting the Right Engine shouldn't be a problem.Isn't operation of the ISO VLV before the ENG GEN are online a must? I mean we start both engines, left and right before engaging the generators, which means the isolation valve must be powered by another source than main bus?Or did I get this totally wrong? Care to elaborate? :+Cheers mate,

[Qavion 19]

"Isn't operation of the ISO VLV before the ENG GEN are online a must? I mean we start both engines, left and right before engaging the generators, which means the isolation valve must be powered by another source than main bus?"Hi, Matt!I was simply proposing a far-fetched scenario where pilots could forget to turn on the engine generators and still be able to get into the air. I'd say it might be possible in real life, but definitely not the right way to do it. To start the right engine, you would definitely need the Iso Valve open. However, if it were open already, then you could start the engine. Unlike some other valves, the Iso valve remains in its last position when (main bus) power is removed (It is purely electrically driven).Hope this makes sense.Cheers.Ian.

[Orlaam 328]

This is true. I've only been in the hobby for a couple years, and I'm busy a lot with school, so my ability to learn a lot about the real ops of these complex planes is limited. If I ever get done with school, I hope to be able to devote more time to learning some aviation stuff! ;)