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TS-IOR
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Joined: Mon Oct 08, 2001 9:44 pm

Mobile Phone In Cockpit :

Sun Nov 14, 2010 8:49 am

Late this evening, i was listening to live ATC from Tunis ACC then the controller asked the pilot of a Biz jet registered in Turkey (callsign was Tango Charlie...) to switch on his mobile phone, in the cockpit, in the air, whilst climbing FL370, on request from his company which was trying to call him ! The pilot said he was unable to phone, but the company insisted. The controller said " they want to contact you regarding restrictions overflying i don't know which country airspace".

I know you can now phone during flight but within specially fitted airplanes.

Is it safe to use his tiny usual mobile phone in flight ?!
Next flight TUN-YUL Tunisair A330-243.
 
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tb727
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RE: Mobile Phone In Cockpit :

Sun Nov 14, 2010 3:14 pm

I've had a flight follower try that before, I don't think they realized it doesn't work at altitude. We have sat-phones in our planes I fly now so it's nice, now they can get us anywhere   

If that doesn't work we call down to an FBO and have them call and relay messages. In very rare instances we can do it via Flight Service Stations. I don't think my phone has ever worked up high though.
Too lazy to work, too scared to steal!
 
YWG
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RE: Mobile Phone In Cockpit :

Sun Nov 14, 2010 3:49 pm

This is what a company frequency is for!!
Contact Winnipeg center now on 134.4, good day.
 
Fly2HMO
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RE: Mobile Phone In Cockpit :

Sun Nov 14, 2010 4:04 pm

From my experience phones are worthless above 5000ft AGL. I have made a few calls from that altitude but reception is sketchy, even though the signal meter may show full bars (it often does at certain altitudes).

Quoting TS-IOR (Thread starter):
Is it safe to use his tiny usual mobile phone in flight ?!

If in VFR during the day, sure. But in IFR, HELL NO.

I've had AHRS failures happen to me twice on the G1000, once when I received a text once and the other when I got a call. Also on our older planes at school the Bendix/King GPS was known to loose RAIM and act strange during calls as well.

Nothing became of it because they both happened in perfect VFR days but the last thing I'd want is an AHRS failure in an IFR approach to minimums.
 
DiamondFlyer
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RE: Mobile Phone In Cockpit :

Sun Nov 14, 2010 4:12 pm

Quoting Fly2HMO (Reply 3):
I've had AHRS failures happen to me twice on the G1000, once when I received a text once and the other when I got a call. Also on our older planes at school the Bendix/King GPS was known to loose RAIM and act strange during calls as well.

GSM or CDMA? I know from experience GSM does awful things to the avionics, but I've never been able to reproduce the symptoms using a CDMA phone. I've had people fly with me before, and I can tell when they have AT&T or another GSM phone, because I can hear it when they get a text or call.

-DiamondFlyer
From my cold, dead hands
 
YWG
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Joined: Wed Feb 07, 2001 11:29 am

RE: Mobile Phone In Cockpit :

Sun Nov 14, 2010 4:25 pm

Quoting Fly2HMO (Reply 3):
Also on our older planes at school the Bendix/King GPS was known to loose RAIM and act strange during calls as well.

KLN 90 by any chance? If so, +1 here.
Contact Winnipeg center now on 134.4, good day.
 
B727LVR
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RE: Mobile Phone In Cockpit :

Mon Nov 15, 2010 2:30 pm

Quoting Fly2HMO (Reply 3):
I've had AHRS failures happen to me twice on the G1000, once when I received a text once and the other when I got a call. Also on our older planes at school the Bendix/King GPS was known to loose RAIM and act strange during calls as well.

Why is it they only happen in flight? Me being an avionics tech, I have never had this happen to me while working on the ground, and I have been around many AHRS and GPS systems....

Quoting tb727 (Reply 1):
We have sat-phones in our planes

I am surpised this Bizjet did ot have a sat phone. THey seem to be more common than not now a days.
I'm like a kid in a candy store when it comes to planes!
 
bri2k1
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RE: Mobile Phone In Cockpit :

Mon Nov 15, 2010 4:23 pm

Quoting B727LVR (Reply 6):
Why is it they only happen in flight?

I hate to open this can of worms. But there is one thing to consider. Most avionics, at least the COM radios, operate at a fixed transmit power. Mobile phones however have a large range through which they can set their transmit power. Different waveform technologies use different methods for power control, but the idea is to maintain a target SNR at the receiver (cell tower) through changing conditions. Most handsets can sustain a range of between 80 and 100dB of fade from maximum receive power, so their transmit power must have an impressive control range as well to maintain the link at those limits.

In the air, farther from the towers and out of the peak area of their antenna pattern, the phones must transmit hotter, increasing the propensity for interference.
Position and hold
 
Fly2HMO
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RE: Mobile Phone In Cockpit :

Mon Nov 15, 2010 5:17 pm

Quoting DiamondFlyer (Reply 4):
CDMA?

'Twas CDMA. Has happened with two different brands of phone altogether.

Quoting DiamondFlyer (Reply 4):
I've had people fly with me before, and I can tell when they have AT&T or another GSM phone, because I can hear it when they get a text or call.

Oh yeah the infamous dit dit dit da dit dit dit daaaaaaaaa sound.

I've had one of my CDMA phones interfere with my PC speakers more than a few times, it's not as obvious as with GSM but you can detect it if you pay attention.

Quoting YWG (Reply 5):
KLN 90 by any chance? If so, +1 here.

KLN 94 actually, same box really.

Quoting B727LVR (Reply 6):

Why is it they only happen in flight?

Oh it happens on the ground believe me. While it has yet to happen to me personally, I know of several first hand accounts from CFIs at my school instructors who had to shut down their phones when they found out the GPS was acting funky during preflight or taxiing.

It would make sense that GPSs are the most susceptible equipment as the cell phone frequency band and the GPS band are very close on the radio spectrum.

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