Just another question here for a MS flightsim Geek who has found himself pressed into service to land a 747because both pilots fell unconscious after a terrible inflight airline meal!! So if he finds himself sitting in the cockpit and the 747 is under autopilot what can he do to radio fortower or control center assistance? Should he try and tune the radios to 1215 emergency channel or what? How canhe do this? Which buttons near the pedestal allow him to tune frequencies and broadcast his request for adviceon how and where to land the plane?ThanksAl (MS Geek)

Why do you ask?You're a self-confessed FS geek right? So you already know...Best regards,Robin.

why should it be difficult to change frequencies on the radio,if one does not know this,he does not have any right to be in the cockpit in the first place ,its my opinion any way no offense,imagine how is any one going to manage to land an aircraft if he cannot even change frequencies on the radio,i had a friend of mine who used to carry a mobile when he was flying cessna in africa,if they were near the airport from where they took of to simulate a radio failure they would use the mobile to let the instructors know they have a simulated problem,may not work with a bigger aircraft!! :( vivek

I think he means how do you know what frequency to call to declare an emergency.Commercial flights are almost always tuned to an ATC channel. The only time they would not be tuned to an active frequency is if you are landing at an uncontrolled airport, which is extremely rare. So, calling for help would only require you to push the PTT button and declare an emergency.

So, calling for help would only require you to push the PTT button and declare an emergency.

I think we are forgetting that the 744 spends a lot of its time overwater, or over vast tracts of uninhabited land. There are 3 VHF radios, none of which would have more than 283 miles range even at 40,000' (assuming the ground station is at sea level).Pushing a PTT switch is no good to you if you:a ) don't know which radio is tuned to which frequencyb ) don't have the correct radio selected on your Audio Selector Panel (You may be talking to the passengers over the PA system :( ) c ) don't have the receiver volume turned up sufficiently to hear the ground station.d ) select the Centre VHF and ACARS is in use.There are lots of PTT switches, but some only work with the interphone system (pilot to pilot, or pilot to engineer).HF or Satcom might be better options for long distance comms, but they come with their own set of operating instructions. No emergency frequency is required per se. MAYDAY with your callsign would be sufficient. HF comms is difficult at times because of background static. The SENS control may be turned down, so you might not hear a callback. Certain frequencies respond better at certain times of the day. If you hear a tone when you push the mic button for the first time, wait for the tone to finish, then transmit (The transmitter sometimes has to tune)SATCOM requires you to select a ground station phone number from a directory. It also requires IRS alignment for voice comms.Certainly not as easy as you might imagine.Rgds.Q>

SATCOM requires you to select a ground station phone number from a directory. It also requires IRS alignment for voice comms.

Very interesting Q. Care to explain a bit more?Paul

I guess there are various ways of looking at Satcom. There is the "data" side which is like texting. e.g. ACARS & FANS requests can go via the Satcom system. The other side is the duplex (two-way) voice comms system. The voice comms system requires a more "high fidelity" method of transmission/reception than text.Some Satcom systems have two antenna systems- One low gain antenna system for data and one high gain antenna system for voice. However, many Satcom systems have only one "high gain" antenna system for both voice and data links. Anyway, to achieve the best reception/transmission, high gain antennae have to be steered (pointed) towards the satellites. They don't physically move... the "movement" is done electronically. However, to steer the antennae, you have to know where the satellites are.. and where the airplane is in relation to the satellites. The IRU's tell the Satcom system where the airplane is.. and other electronic wizardry tells the Satcom system where the satellites are.Satcom normally has 6 voice channels. Passengers (with lots of $$$) can also use the Satcom system to make phone calls via their seat handset/audio controller. The cockpit, of course, has priority when it come to making phone calls. To make any phone call, of course you need a phone number. The MCDU Satcom menu usually has a mini-phone book/directory. Pilots can make quick selections using these numbers. As well as dialling the number, the pilots must also use the Audio Control Panel SAT 1 & 2 buttons to enable them to use their headsets/boom mics to talk via Satcom. Depending on options, you could even phone home using the cockpit Satcom system : )Hope this makes sense.Cheers.Q>

Thanks everyone and thankyou Qavion, The extra details you provide are much appreciated. It takes a lot of study to learn all of that.Al