personal device interference / EMI

[blind pew]

Is it still a problem?
Had a little contretemps with a pax who insisted that his mobile phone didn't constitute a problem during approach if in flight mode. Flight deck member told me the company line was not to report it to the authorities as it would involve a delay to the return flight.
Spoke to flight operations inspector of the relevant authority - no names no pack drills- and didn't get a satisfactory answer.
In my old company the autopilot hard overs were believed to be caused by gameboys.
A friend had total hydraulic failure pages appear when he transmitted on HF. Boeing added further screening on the TX circuit which solved the problem.

[BOAC]

I guess the 'does it/doesn't it' argument will go on for ever; I have operated for carriers who
1) Ban any 'mobile' devices during take off and landing OR
2) Accept 'Flight Mode'
but personally never had more than audio interference

It really depends on your company's policy and what instructions are given to pax by the crew. If said pax operated contrary to company policy it is for your company to take action if desired, as in ban the pax from future travel.

[HeadingSouth]

... a mobile phone in flight mode cannot interfere with the aircraft's system as all transmitters are switched off. This includes bluetooth, WiFi and other available transmitters.

On some elder phones, however, you may be able to activate WiFi when flight mode is selected. Strange...

[underread east]

And on some newer ones too. Iphones do switch all antennae off when in flight mode, but also allows you to turn the wifi antenna back on again with the others remaining off.

[Greenpilots]

Our company says that "all electronic equipment has to be switched off for take-off and landing", which is always a good argument. Flight mode is tolerated in cruise (your I-Phone is nothing else but an I-Pod then).

Cheers

[Piltdown Man]

This one is very simple. 'Sir, please will you turn your electrical device off.' Passenger complies, no exception. If your operations manual says 'off', then off it shall be. If your colleagues in the flight deck are more concerned about schedules than backing you up may I suggest you fill in a CHIRP form.

PM

[Bruce Wayne]

Have to agree with Piltdown Man,

While flight mode does shut down the processes that impliment transmission/reception of signals the, there is only the word of the user that it has been put into flight mode.

There is nothing then stopping the user of placing back into operational mode.

How many times have we seen people jump up and unload their carry-on's from Overheads while the aircraft is still taxiing to the terminal, despite the announcement to remain seated until the doors are opened.

Another point to consider is software vagaries, my phone has elected to come out of flight mode (cinema) and also to revert back to data download while roaming, despite the function being turned off.

The only sure process is, if the operator or crew requires it off, then turn it off. no argument.

[HeadingSouth]

...you're always left with the passenger having the possibility to switch his transmitter on after the FA's have passed by...
Had a case years ago when leaving AMS as SLF and saw a bloke in the cabin talking to his mate on the cellphone seconds after the wheels left solid ground...

[Deltabravowhiskey]

Actual occurrence, GSM/3G device left in transmit. Device while searching for a carrier (inflight) caused interference with the pressurization system. System operates on AC (400hz) voltage, GSM with its known ability to interfere with audio systems appeared to cause enough distortion in the frequency that the outflow valves began to cycle (hunt) causing a mild fluctuation in cabin pressure. After the device was restored to flight mode, no further issue.

GSM devices can broadcast with an initial pulse of over 2watts but then drop down to tenths of a watt. These devices if placed near speakers will cause an aural distortion in the aicraft systems.

Autopilot systems being AC controled could be affected depending on the proximity of the servo's to the GSM transmitter.

What you essentially cause is a VFD or Variable Frequency drive effect in the system since they are intended to run at only a specific frequency.

[flipster]

see here for concerns - there is an awful lot we take for granted and the testing and trials data volume is small.

http://www.pprune.org/safety-crm-qa-emergency-response-planning/380379-electro-magnetic-interference-v-avionics.html

[Denti]

Had a small occurence a few years back when we had to break off an approach and enter a holding because the tower had received a bomb threat. During the hold we noticed fluctuating vibration indication around 4 but occasionally up to max without any other indication nor any vibration. Made a PA to please switch off all mobile phones and PEDs, indication returned to normal. Was a 737-300.

Nowadays it's all electronic devices off for take off and landing, but during cruise flight mode is perfectly acceptable. FAs do miss ebook reader on checking a lot though, nearly never get asked to switch off my kindle.

[blind pew]

thanks for the replies.
JI feel uncomfortable being a pax on a flight descending into an airfield surrounded by mountains with a :mad: playing with a Iphone whilst the carrier has an unofficial policy to ignore their own rules!

I remember the Basle vanguard crash where the EDF High Tension power transmission was on the same frequency as the local NDB!

When my home stereo is in the standby mode - as in off but plugged in - I can hear a pulsing through the speakers seconds before my nokia phone receives a call or text!