Mobile Phone Sends Jet Out Of Control
 

This happened in April, but reported in todays Sunday Mirror

Embraer 145 on approach to Manchester sent out of control when woman switched on her mobile phone

Aircraft "careered across the sky" as "instrument dials and electronic systems seized up". Pilot notified crew and passengers to prepare for emergency landing by opening the cockpit door, at which time he saw the said stupid bint on her phone, told her to turn it off, and the problems immediately went away

I can reproduce the article if needed, but its the standard article with gratuitous use of the phrases "disaster!" "lost control!" "avoiding action!" "crash moments away!"

Anyone know any more? feel free to delete/point me in the right direction if its been discussed before, couldnt find anything via search

It's reported by the media so it's safe to say that the majority of the report is a bunch of cow flop, but there is a distinct chance of a mobile doing odd things to the aeroplane's avionics.
I've seen it happen on a 747 on the ground, with the pressurisation system so they really can affect the systems of some planes.

Never mind mobile phones....a certain middle east operator had a B747SP do a high dive in the mid-eightys mid-Atlantic because the aft outflow valve fully opened when they called Gander on the #2 HF.:eek:
Seem to recall that this was a on-going problem with this particular aeroplane.

Take a look at http://news.bbc.co.uk/1/hi/england/2324259.stm

Here is the Mirror version . . .

http://www.sundaymirror.co.uk/homepa...l&siteid=81959

I have my doubts. I'd be more confident if I read The Economist's version.

i wouldn't be suprised if phones are now banned in the cabin. Imagine 10 terrorists in the plane all turning their cell-phones on at once and making calls. :cool: Hey, whatever excuse works for the regulatory body. :rolleyes: :rolleyes:

An engineer told me .... hang on, that sounds like a song .... Anyway, an engineer told me that some cellphones operate within a quarter of one percent of DME frequencies.

Hearsay though, anyone confirm?

>>...an engineer told me that some cellphones operate within a quarter of one percent of DME frequencies.
>>Hearsay though, anyone confirm?

Well, DME runs from 962 to 1213 MHz (see http://www.rduafss.faa.gov/navaids/dme.htm ).

GSM 900 has an allocation from 925 to 960 (paired with 880 to 915 MHz, see http://www.gsmworld.com/technology/s...quencies.shtml ).

The gap from 960 to 962 MHz is 2 MHz which is indeed less than .25% of 960 which would be 2.4 MHz.

The engineer is right.

British phone freqs may be more dangerous than others (especially if they can topple a jungle jet <g>) according to this article: http://abcnews.go.com/sections/livin...one000510.html

One would think (purported) serious control difficulties on approach would cause the AAIB to investigate. I find no reference on their site.

I would not get so hung up about how close they are in frequency, closeness causes desensitisation or blocking, and equipment is usually designed to cope with this. What is harder to design to is protection against harmonic interferance, either direct or combined with additive/subtractive elements internally or externally. Taking a very simple case:

You want to listen to 121.5Mhz. In order to handle this frequency the radio needs it converting to an intermediate frequency, say 10.7Mhz. The radio needs to run an oscillator at 110.8Mhz which when combined with the required signal gives 10.7 Mhz (121.5 - 110.8 = 10.7). However, another frequency of 100.1 Mhz also gives 10.7Mhz (110.8Mhz - 100.1Mhz = 10.7 Mhz). Therefore as well as receiving 121.5 the radio will receive signals on 100.1Mhz (probably KISS FM in London UK).

THe above is over simplified to give clarity, techniques such as multiple intermediate frequencies etc can overcome the problem.

But now add in a mobile phone. These frequency hop whilst in use and use pulsed modulation (particularly good at producing rich harmonics) Therefore there is a good source of frequencies for any radio equipment to "mix" with causing problems.

In practice much mobile phone interference is also caused after the RF stages in the more poorly protected audio stages.

So whilst it is possible to design in protection it is easier to reduce the opportunity for it to occur (ie. switch the damn things off).

I read about devices that restaurants etc could buy to disable all mobile transmissions in the room and render phones useless. I would have thought it was worth developing these for use in aeroplanes so no phones worked when engines were running. Yes, I know they would use transmissions themselves, but people will never be stopped from using their phones in flight as long as they work.

As a side issue, Notso carried out 'experiments' with an Orange phone a few years back. It never worked in the air. Presumably the cells detected a flooding effect and cut you out of the system, but mysteriously on the ground it worked, so how come these people can get their phones to work? I am also reliably informed that Virgin phones similarly don't work in the UK when airborne.

Hey my Virgin phone struggled to get a signal in the middle of London - not surprised that you couldn't get a signal at altitude.

Yours, now a BTCellnet user,

Isn't it because the bases and phones are relatively short range transmitters, which is why you can go out of range so quickly? I think that's also why you hear so much beeping on final approach, as the phones finally get close enough to bases to pick up the SMS messages that have been queuing to be delivered.

Of course, that's the part of the flight at which I think I'd least like to experience mobile phone-induced LOC ...

I read a report about two years ago relating to a helicopter which experienced a cargo fire warning, fortunately while still on the ground. An active mobile phone was found in the baggage, switched off and the flight continued without incident.
After September 11th, I would think that any inflight emergency would result in many passengers picking up their mobiles and trying to say goodbye, particularly in the caser of cabin crew with marginal english describing bomb threats!
I agree that a ban would be the only answer.
ATB, PTC

about 2 years ago was on an embraer145 departing GLA when an
engine shut down on takeoff roll, returned to stand and an
engineer said that it was due to a mobile phone being switched on and recieving a call, checked PAX in rear 3 rows of a/c and found phone switched on with a text message recieved took 40 mins to reboot computers.

Wot rot
 

My diesel landy departed GLA with vague steering and oil leaks all over the place. I found my nokia on in the back, switched it off, now the car performs like new!
Perhaps it was the same sort of phone as in the Embraer 145 and all the other mobile works of fiction?

maybe its the bermuda... err the london triangle thats causing all these problems? :cool: :cool:

Very funny. Well I got this enormous credit card bill that made the whole place rock, and I turned off my mobile phone, and guess what? It was still there rockin'!

Get real people!
I fly the 145 for a living and have gotten airborne on loads of occasions with one or both of our personal phones inadvertantly left on. the 'chirrp' as it loses the cell is invariably heard on the i/c prompting a 'switch off' asap. never seen any evidence of interference, and that with the phone(s) on the flight deck!
don't believe everything you read in the papers.:)

This thread engages at least two different aircraft-related issues:

a) In an era of ubiquitous cellphones and various other portable electonics that can transmit complex powerful signals in and around aircraft, a high degree of RF-resistance & microwave toughness should be considered in the design specs and the maintenance standards for every component on passenger aircraft.

The standards should apply not only to the obvious resonant interference with nav/comm systems, but also particularly to sensors and control actuators throughout the aircraft, and also the connected wiring + innards of analog and digital control circuits and computers. Virtually everything electrical, in sum.

Goal: Properly designed and maintained passenger aircraft should be immune to the effects of cellphones and other (out of band) onboard RF sources across the entire spectrum.

b) Even when and if the standards of a) are uniformly and stringently effected, some RF-introduced random problems with avionics, controls, and systems will continue to occur, just as mechanical problems do. Many will be for the same reasons: vibration and corrosion effects can gradually unmake the high-quality electical joints and seals needed for robust RF insensitivity.

Given that a) isn't going to completely happen for some while, and b) is going to continue happening forever, limits on use of inflight cellphones continue to be reasonable.

However, the appropriate post-incident response to suspected cellphone-type systems malfunction incidents should be a full writeup and aggressive troubleshooting to find, repair, and document the faulty subsystem. One may think of the troublesome phones as canaries for fundamental problems that require repair in any case.