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Fancy Navigator
18th Oct 2003, 04:47
Hiya
Sorry in advance if the message is not at the right place....
I was thinking about taking my airband receiver when I next fly, but I have just been told that it is forbidden to switch on an airband receiver when you are on board.... The reason given is that it interferes with the aircraft systems....:rolleyes:
Any thoughts please.....
Cheers

Faire d'income
18th Oct 2003, 07:50
I don't think it would interfere with any aircraft systems as it should be a simple vhf receiver.

However it could be seriously disruptive to passengers. It is reckoned 30% of all passengers are at least slightly nervous. That means one behind you, one in front and maybe one beside you. No responsible airline could allow any pax scan the airwaves during a flight.

What if they heard the word Mayday ? Do you think you would have time to explain to them it wasn't your flight? Would you know yourself???

Never underestimate the danger of frightening people on an aircraft.

As an aside I was on a flight one day where one of the cabin crew told me an elderly woman could hear us talking to ATC on the radio . I asked the predictable questions as to how but was told it was telepathy! :hmm:

BEagle
18th Oct 2003, 15:50
No, you certainly may not use an airband receiver inside an airliner. Nor any other radio for that matter (except a laptop 802.11b in approved circumstances).

Any superheterodyne receiver contains a local oscillator which may radiate sufficient RF to cause interference with aircraft navigation systems, particularly VHF based systems.

Th elderly lady may well have been picking up interference on her hearing aid?

The aircraft wiring itself in some light ac can actually act as an aerial! If you flew a Bulldog near Daventry, you could hear BBC LF transmissions in the background.........

Avman
19th Oct 2003, 00:21
I don't believe that a VHF RECEIVER will cause any interference. And you can always use an earpiece so as not to upset those around you making all that racket playing their computer games or listening to loud music!!!

Mike Blackburn
19th Oct 2003, 00:45
I would be very careful about taking an airband receiver onto an aircraft. Bear in mind that in many countries it is illegal to listen to aircraft transmissions, (although, bizarrely it seems that it is not illegal to own an airband scanner!) and it would certainly be emabarrasing to be arrested on arrival. The other point is that one would probably, based on the performance of scanners I have seen, only be able to hear your own aircraft's transmissions, and some of those around if they were close enough. A piddling 10cm aerial is no match for the serious hardware aboard a commercial aircraft.

However, as always, I stand to be corrected..

TightSlot
19th Oct 2003, 03:55
As cabin Crew, we're told (at least in my company) that this kind of device is not permitted because of the potential for interference. I can't debate the technical rights & wrongs as I don't know enough, but I do know that if I saw you with this equipment I would ask you to turn it off, and if necessary, double check with the Captain: From experience, I'd say he'd back me up.

Wouldn't it be easier (and safer) not to take it into the cabin? I see nothing but troubled times ahead if you do.

Faire d'income
19th Oct 2003, 05:32
Don't accept the argument about an earpiece. Refer to my question about whether an non-flying pax would cope with hearing the word mayday. Would any responslbe skipper or airline take the risk.

Tightslot how would the cabin react if the guy with the earpiece incorrectly jumped up and started screaming that the captain has declared a mayday?

Beagle like I said I asked the predictable questions, it wasn't a hearinh aid . Also not just light aircraft wiring sometimes the ground crews cable to the aircraft can act as an aerial.

Avman
19th Oct 2003, 13:55
Faire D''ncome ,

Are you aware that United allow pax to listen in on ATC tx on their o/b audio equipment? And that others allow pax to watch take-off and landing on o/b video equipment! So, you can already (legally) listen in on a potential "mayday" call or even watch yourself crashing! Your arguments are foundless on me. Most of you, including cabin crew, are basing your answers of "receivers may cause interference" on ignorance.

TightSlot
19th Oct 2003, 15:17
No, Avman, Cabin Crew are basing their arguments on existing rules not ignorance. If you disagree with the rules, then get them changed in the accepted way. Cabin Crew are paid to implement policies and procedures provided by employers and legislative bodies. Why should they be patronised or blamed for correctly doing so?

Faire d'income I reread my original post having read your subsequent one: Since I made no suggestion as to an earpiece, nor supported the proposal to take the equipment onboard, and my post was pretty easy to comprehend, it is unclear why you write as you do?

In conclusion - In an overwhelming majority of cases, either the law, or company policy dictates that you may not use this equipment on board, so don't do it. Your later defense of "Some smartarse on a bulletin board told me it would be ok..." will look increasingly thin with time. Avman's suggestion of flying United might be a solution. I listened in, for a while, with them on triple 7 - frankly, after 5 minutes in the cruise, boring, but whatever rings your bell

Avman
19th Oct 2003, 16:41
Tightslot ,

I wasn't refering to the rules. I was referring to the statement that such equipment will cause interference. Of course cabin crew must enforce company rules but that doesn't mean that they can categorically state that such equipment can cause interference. They only believe this because of the rule and not from any scientific knowledge.

Faire d'income
20th Oct 2003, 01:18
Tightslot you misunderstood me or I didn't make myself clear. The earpice was suggested by a previous poster. I was just asking you as a Cabin Crew Member to point out what might happen in a cabin if a passenger jumped up shouting that the captain has declared a mayday.

This is what I suggest is a possible scenario of allowing a passenger with no knowledge of Air Traffic Control listen to transmissions while on board. He could cause panic for no reason.

Avman I presume the cameras are in the cockpit. If not ignore this but if so I can't believe a US captain would leave himself so wide open to litigation.

Every 40 hour ppl holder with an opinion would try to sue for anything they could think of. Just think. ..you flared to late/early...you braked too hard/late...we saw the runway and you still did a go-around....kicked off drift too late/early.

And imagine if you genuinely erred in some minor way!:bored:

Does this really happen?

Avman
20th Oct 2003, 03:58
I flew SJU-JFK some years ago on an American DC10 with a video display of our departure and arrival - this even after their ORD crash! I also recently read that a major airline (non-U.S.) is introducing this facility to its pax but I can't remember which. Perhaps someone can help me.

Noah Zark.
20th Oct 2003, 04:16
I flew on an Emirates 777 Dubai - Heathrow in 2001 which had two real time video cams , one looking straight down (quite good at altitude) the other one looking straight ahead, which the Captain left on during approach, landing, and taxi to the gate.
Top Wallah! :ok:

radeng
20th Oct 2003, 20:28
The local oscillator radiation from an air band reciever can cause intereference. Even worse is a VHF broadcast receiver - there was a well documented case some years back in the USA where the football team would keep turning on the VHF broadcast radio they had with them and the oscillator radiation caused the VOR to go wrong. Eventually the captain (deliberately) landed at an airfield out in the wilds of nowhere....

If the airband rx has been self certified by the manufacturer (which can be done ) as a broadcast receiver, then in Europe it only needs to meet the radiation requirements of EN55013, limiting the radiation to -13dBm or 50 microwatts. Aircraft comms receivers typically have sensitivies down around -107dBm or around 20 terawatts - that's 20 times 10 to the power -15! There are no EMC requirements on receivers with internal batteries. Were it to have been otherwise certified, it would need to meet the general requirements of -57dBm or 2nanowatts. Limits in the USA are somewhat less strict.

One problem is that the screening of feeder cables to aircraft antenna doesn't always retain its integrity with age - there's movements and chafing, and the shielding braid can get damaged while still allowing the antenna to perform adequately for its usual purpose. So the oscillator radiation may easily cause a problem, although it would depend what channel was being monitored, and what channels were in use in the aircraft.

The use of 802.11 WLAN (or Hiperlan or Hiperman) also has some problems, although these will mainly be with MLS, unless there's an EMC immunity problem - which is by no means unheard of.

So I personally don't want to have anyone using an airband or broadcast radio - or mobile phone - on an aircraft I'm flying in. By the way, in case it's not obvious, the user name radeng refers to my profession - radio engineer - so hopefully after forty years, I know a bit about it by now!


DON'T DO IT!!

Pax Vobiscum
21st Oct 2003, 18:50
Avman

Finnair have these videos on their new 'buses. Sadly the only time I've been on one was a night flight.

luoto
28th Oct 2003, 00:24
Finnair have these videos on their new 'buses.
Yes, I am so used to NOT seeing them that after watching the safety info with the funny American sounding bloke I went back to read during taxi, then we were at a holding line.

Then for some reason my brain recognised seeing an aircraft whizz right in front of my eyes, yet all the other recognition stations said that it should not happen ! It took a few intervals to realise that it was on the screen ahead and that it did, in fact, correlate to what was happening l and r.

Nice to see ! Not sure what company procedures are as some switch off on taxi. Some dont and it did amuse nearby children to see the funny man "waving" at the aircraft (!) as we came to the gate.