Can we separate the boll...s from the facts please chaps?
1) I was short-haul not long
2)I did not say I knew better....
3) the word is discreet, I was not hiding it from the crew, but was simply not drawing attention to myself from other pax who might wonder what the device was
4) the only restriction mentioned by crew was mobile phones, eg other pax used laptop PCs with no comeback.
5) As atomic implies the US have legislated and looked at the facts - IIRC FCC class B basically guarantees that the device emits less than a certain power level - and drawn a conclusion whch allows use.
6) Slasher mentioned Garmin units designed specifically for aviaion use - AFAIK the main difference is in the information calculated and displayed - not the circuit design or physical casing etc. I believe I read here before that many PPLs use the 'domestic' market GPSs as handhelds with no ill-effects.
7) Huggy, exactly what 'rules' do you refer to please?

Willing to be corrected - but facts please (yes I do realise the professionals love rumours hence this site's title...)

Sorry HungMonster, I didn't see your earlier question.
I agree, your first response was "polite, friendly and informative". Rather formal, but still polite, friendly and informative - and it even had a witty twist in the final para.
I only "singled you out" over your second post because you always (I exaggerate) seem to refer to calling the police if someone disobeys a rule or your 'lawful command'.
You suggested the PPL was concealing the GPS because he realised that what he was doing was "stupid, irresponsible and illegal". Do you really think that's why he conceals it?

As you can see from the posts, not everyone agrees with you about a hand-held GPS, whatever the "rules" say - if anything. Our safety chat doesn't mention GPS as far as I know.

You're not going to approve of this but, I admit I use my discretion over (bold for emphasis)some rules. Many of us do - don't you ever, ever?

C'mon - despite what you say on Prune, would you really call the police if some pax was caught with electronic equipment on after the PA instruction to switch them off? Surely a ticking-off would be enough?

[This message has been edited by neutral99 (edited 08 January 2001).]

1) My company tells passengers in the initial PA announcement that phones must be switched off at all times, and no other electrical or electronic equipment may be used while the seat belt sign is switched on. At other times, passengers may request to use them. Therefore, depending on the phase of flight and type of equipment people want to use, all is at the discretion of the crew. If problems with aircraft equipment come to light, the cabin crew know who to ask to switch what off.

2) Passengers using equipment "surreptitiously" or "discreetly" without asking the crew implies to me (and to many others with whom I've discussed this) various possibilities - none of which I like terribly much.

3) Under the circumstances Slasher described, provided they ask in advance, I would have no problem at all with someone using a handheld GPS, provided it was one designed for use in an aircraft. I would, however, prefer that it be switched off for the approach.

4) As I mentioned in my initial post on this thread, I have heard worries from some quarters that it is possible some suicidal passenger may want to use a GPS to be sure they are over water before somehow bringing the aircraft down, thus avoiding investigation of the wreckage and possibly invalidating life assurance policies for their dependents. My personal view is that this is a little far-fetched, but there have been allegedly suicidal pilots in recent years, and why not suicidal passengers? It is merely a possibility, and I believe the likelihood of possibility becoming reality is very remote.

5) If it was discovered that someone on board my aircraft was deliberately and knowingly breaking whatever rules are there for flight safety, my instinct would be in the first instance to ask the #1 to issue a stern warning, and request an electronic device be switched off. Depending on the response, I would probably take it no further. However, if the response is a suggestion relating to sex and travel, or they are found repeating their performance, another warning about the possible consequences to them (viz., possible blacklisting, arrest upon landing, etc. etc.). Only a third time would I consider having the police meet the aircraft upon landing. And beyond that, I would consider diverting and landing asap if it appeared to me that the safety of the aircraft was being endangered.

6) I don't work in the IT market, which seems to have more than its fair share of pondlife among its passengers considering that because they're on holiday they can do whatever the heck they like. Most of our routes are largely business routes. Frequently people ask if they can use laptop computers, and there is no problem there. Moreover, the passengers are often very frequent flyers with us. The benefits of this are two-fold. Firstly, they know us, and respect the service we provide. Secondly, they know the likely implications for them if either they were to be refused carriage in the future, or a letter of complaint about them were to be sent to the person in their company who makes the flight bookings.

[This message has been edited by HugMonster (edited 08 January 2001).]

As far as I know, US airlines are mostly uniform about the pre-takeoff announcements on the use of electronic equipment. Although I've flown alot on non-us carriers, I can't remember exactly what the briefing says is allowed and is not allowed. I think we can all agree that as a condition of passage, passengers must follow the safety rules established by legal CAA authorities and the airline itself. If GPS' are authorized, then by all means, have at it -- although I personally don't see the thrill there -- I'd rather check the inside of my eyelids for light leaks. BUT, as a matter of consideration for others in the airplane, my own safety, and the safety of the aircraft itself, I WILL follow the legal orders of the PIC and crewmembers - just as I follow the flight regs and rules of the country I'm flying in. In the last few years there seems to be a significant increase in the disregard of rules by passengers who feel they are above them. It's an ugly thing, and one day, somewhere, somehow it may cost a lot of lives

Hey ACARS fyi Im not arguing with anybody! All I simpley said was that I give a bit of latitude with pax who know exactley what they are doing and satisfy me in the process. I cited a Yank CPL holder in this case.
As far as the Great Unwashed are concerned Im with Hugs 100%. In fact Im even more bloodey strict. Give the buggers an inch and theyll take 10,000 miles. An example was going into TPE one evening. An Unwashed wanted to use his laptop which I gave the ok. During descent the (737-300) EFIS Map suddenley shifted 8 nm left and the ILS went tits up! On-board investigation showed the idiot with the laptop had connected to the internet via his handphone and was getting the TPE closing Stock prices, and his mate beside him was talking to there broker through his handphone!
Storey doesnt stop there. These dicks were so hung up on there business they ignored the stewardesses instruction from ME to turn these things off! It took me to come back and literaly rip the bloodey things from the hands of these dorks. Pity we werent inbound to my home base Ha Noi. Theyd have been dragged off in chains on arrival and hauled off to the lockup for a month till the "trial" came up (communism does have its advantages!). Lesson learnt: dont give the Unwashed ANY latitude whatsoever!

[This message has been edited by Slasher (edited 09 January 2001).]

As a humble pax who spends more time in aluminium tubes than is good for him, I have to say that the whole area of "electronic devices" is pretty confusing, primarily because there seems to be little consensus amongst airlines as to what is permissible and what is not.
Some for instance do permit the use of personal CD/MD players in flight (a personal godsend if you seen the movies n times before), whereas some do not. Some allow MP3 players, some do not. Some allow the use of mobile phones until the doors are closed, some not on board at all. Some specify a wide variety of "prohibited" items in the in-flight magazine (the only really appropriate source of information since PA quality in aircraft is so variable), and some just a vague list (and personal GPS units don't yet figure prominently anywhere, I've found).
The "best" one I had recently was an airline that didn't think I ought to use my (non-CD-equipped) laptop in a business class seat in which they had very publicly provided a working PC power socket!
You have to remember too that most pax do not understand the finer points of electronic radiation and therefore do not realise that something as apparently passive as a personal CD player can, it seems, endanger a fantastically sophisticated modern aircraft.
So, to pre-empt the situations that get the likes of Hugmonster so worried, I suggest that airlines:
(1) Somehow agree a common set of rules in this area, and
(2) Produce a straightforward leaflet for providing in all seatbacks that simply explains, in ways that most pax can understand, why all these toys are so apparently dangerous when used in a modern aircraft in flight.
That should then avoid any unpleasantness from those who might think that they know better.

GPS aviation units, generally, can not interfere with A/C electrical systems. Something about the circuitry design. However, ALL other electronic devices do generate some kind of electrical signal, even if that device is only a receiver. If you happen to be sitting in the wrong spot, this signal MAY set up some kind of harmonic reaction in nearby wires. (Lots of wires in an aircraft!)This could cause the wire to become, in effect, an antenna. Not very powerful, and certainly not enough to be classed as harmful radiation.
However, this wire is now an antenna for the electronic device, as well as serving whatever use it was designed for. Results are unpredictable. Slim chance of interfering with A/C systems, but there is a possibility, however slim.
Remember something else. If someone wanted to build a resturant or bar using the same design as an aircraft, with huge quantities of fuel and electrical systems in such close proximity to the customers, it would not be allowed. Too much risk!
Now, do you really want to take chances, however slim, at 35000ft with something deemed a hazard when on the ground?

The Captain is the Boss, and what he says, goes. Even if he is ignorant, ill mannered, and wrong, he is still the Boss. If you can't accept that, take a train or ship instead. Turning anything on 'in secret' shows that you know you shouldn't, thats WHY you are being secretive. Might make you feel smug, but go play your games somewhere else.

Seloco, since (obviously) different aircraft have different equipment of varying ages and sophistication, it is not really possible to have a common standard. Older radio equipment is rather more susceptible to interference, but more modern does not necessarily mean better in this regard, since higher-tech equipment such as Slasher's moving map display are fairly vital to navigation, and my aircraft doesn't even have one.

I must admit that I am surprised that some airlines allow passengers to use mobile phones after boarding, since this could upset INS position initialisation, which usually is accomplished by a DME/DME fix, or VOR/DME or whatever the best fix it can get is. Much equipment, however, you can simply enter an airport and a stand number and it then knows from its internal database where it is.

I agree that a note, say, on the Safety Briefing Card might be a good idea. It would need, of course, to be displayed in pictogram form to save language difficulties. but I'm sure that is not insuperable.

I'm not particularly surprised at your recent "best" problem trying to use a laptop. It is quite possible that there was some minor unserviceability with the aircraft equipment that does not stop the aircraft flying, but does mean that unusual extra rules have to be imposed. It doesn't necessarily mean that the airline staff were just being stupid, difficult and unreasonable!

If you've seen the movie n times (where n is a large, positive integer) before, then how about reading a book, or listening to one of the aircraft's IFE channels?

As far as "unpleasantness" is concerned, I would be very worried if the approach from the cabin crew was anything less than polite and friendly. If not, then a letter to the airline might be in order. If, however, the response the crew gets is less than they would like - in other words, switching off the offending article, then things are going to start getting slightly warmer...

Put simply, if the crew tell a passenger to do something for the safety of the aircraft, and he refuses, then the consequences are not going to be pleasant for anybody.

HugM,
I don't think a note on the safety card would do much good. How many pax ever read them anyway?
Also, to go a little off-topic for a moment, how many pax really listen to the safety briefing given by the F/As.
I always laugh at the guys who act bored and make a point of reading newspapers, looking out the windows, etc., while the F/A is giving the speech! Same mentality as the secret GPS, mobile, etc., users! They are important and cannot be bothered!

NIMBUS is spot on with his answer.

Any item that emits EMP [including your computer etc.] - Yes they must if they use any form of AC, has the potential to propogate electromagnetic energy across any 'close' wiring. How close - Back to the piece of string theory.
[pure electronics fundamentals really].

DO you know what a 'local oscillator' is? - Any Transmitter AND Receiver has one - therefore they are all transmitters of sort - albeit low power.

Any pure DC powered device emits another form of EMP [Mainly Magnetic Flux] - Minute amounts of which could be sufficient enough to cause wiring to become antennae - or worse, become an oscillator should the wiring within close proximity possess the right amount of shielding [to form capacitance]. Capacitance and Coil [Magnetic] = Oscillator=Transmitter

Put your computer next to your clock radio one day and enjoy the interfenence.


The Big aircraft and Avionics companies go to great lengths to create AIRWORTHY bits of Kit. They include trials of EMP and 'leaks' of EMP. - At great cost.

Of course some shielding and 'localised' effets of various areas of the airframe must be considered, and flight trials and test flights attempt to identify vulnerable spots in order to provide maximum shielding.

Those video screens and in flight entertainment systems dont come cheap. They too will have gone thru extensive AIRWORTHINESS acceptance procedure and protocols

You should see the vast procedures associated with re-wiring any component - especially those with the older compass systems that actually still use Flux Valves.


Whilst you may say that 'nothing has happened in the past' when I used my phone while airborne, can you GUARANTEE that it will not create an EMP problem that you are un-aware of?

As to the GPS - It would be DC powered, but must contain some ofrm of AC oscillator to receive. It is unlikely to cause any problems, but can you guarantee it without some form of Documented Flight Trial or Test Schedule.

Flight Safety is not a gamble.

Different airlines have different aeroplanes with different aircrew - all different situations.

It may well be a hazard to use a particular item on a particular aircraft at a particular time. Safety is of paramount importance and should NOT be compromised.

The thing that is (and no doubt will continue to be) confusing for passengers is WHY a particular item of kit may not be used. If you wag your finger and say "DON'T do that, you naughty, bad person!", people will react, but not necessarily in the way in which you hope or expect.

If you say "we advise that you don't do that, because there is a risk of this happening..." then the response will be more favourable and the instructions will usually be complied with. If they are not, then read the riot act / call plod etc, as you suggest.

On a recent flight with Braathens in Norway, I requested that the F/A ask the Captain if I would be permitted to use a GPS12 during the cruise. She went to the flight deck, asked and returned with a polite but negative response. No problem.

On an earlier flight from ABZ to LHR the Captain responded with an invitation to visit the flight deck so that he could have a 'play' with it. He gave the impression that he considered the SkymapII better than the kit they had! (Should I be worried by this?)

Last week on an SAS flight the same request for use of a GPS12 was met with a decidedly frosty response. The F/A strode up to the flight deck, drew the curtains closed, whipped them open again 2 secs later and strode back with a curt "Absolutely not! ...the Captain say's it's interferring with the flight instruments".

1- she didn't even have time to ask the question, let alone give the Captain time to check or even give a response, and
2- it wasn't actually turned on at the time !


Where a written tech. recommendation states "...transmitters must not be used..." it seems it is often translated into "..items with an antenna may not be used..". This is then taken to mean items which include a receiver or a transmitter, be it in a radio or other piece of equipment. What was the famous misheard instruction? "...gone to a dance, send three & fourpence..".

As previous postings have stated, the FCC classification should be sufficient clearance for the equipment to be used. Now, it may be that a single unit does not emit sufficient radiated power to cause a problem. Can the same be said of several (ten/twenty) units all operated in close proximity? (Has any study been done into the collective output power of 400 digital wristwatch alarms going off at the same time?).

If the reason for the ban is actually that the aircrew do not wish people to know where they are....well! :rolleyes: Maybe it's just easier to say 'No'? It contains only two letters as opposed to the three in 'yes'.


On the subject of potential hijackers / suicides etc; if they wish to, they will probably use a GPS anyway, regardless of the F/A's announcements. 6ft 180lb Guy with a firearm and an attitude, versus 5ft 110 lb hostie with a pointy finger. Hmmm - who do you think will be taking more notice of the other?

As I said earlier safety is not a matter for negotiation. If various items of equipment pose a hazard during certain phases of the flight, then they should not be used and the reasoning made clear.

Where it is plain that they do not, then where is the problem? What EVERYONE needs is reliable and accurate information, not a rap on the knuckles at morning assembly and a blanket ban because......well, just....BECAUSE!

Anyone from Garmin, Magellan, Bendix/Skyforce et al care to comment? How about you guys at Boscombe?

Can anyone explain why cassette players are O.K. yet CDs and MiniDisc players cause a problem? I would have thought that the older power-hungry cassette players would whack out more radiated energy than a CD or MD. http://www.pprune.org/ubb/NonCGI/confused.gif

Why should the power consumption of a device mean that it would "whack out" more energy. It is all to do with the frequencies generated internally within a piece of kit and how well those frequencies were screened. A cassette player has no high frequency energy as a celluloid magnetic strip rubs over a magnetic head. There is bias on the tape, but that is still within the audio band, not radio frequency. A CD or MD on the other hand has demodulator circuits to "step down" the very high frequency encoded info from the disc into a range we can hear. That`s where the problem could lie. In comparison, a mobile phone deliberately transmits around 5 watts of UHF radio energy, hence the problem with mobiles on board.
Bob

.... was thinking in terms of the older technology being less efficient with regard to power consumption and the generation of interference. I'm not an electronics engineer and so am grateful for any information people can supply! Thanks.

An interesting thread indeed.

We regularly use the Garmin GPS II+ in our training aircraft to track where a student has been on a navigation exercise ,(very handy debriefing tool when displayed track can be shown on a computer screen) with no effect on aircraft performance or systems.

These aircraft arent cessnas or the like, but turbo prop jobs with engine management computers and electronic flight display sytems. The GPS is attached by velcro over the intrument panel, so is nice and close to lots of wiring and instruments.

After all that, just because nothing has not happened to date doesn't mean that something can't go wrong. Remember that Murphy's law still applies.

If one wishes to use electronic equipment, be it a GPS or Scanner or so on, ask for permission to use it. At the very least all that can happen is that the answer will be, "Sorry No". If you are permitted to use your gear, and something unusual occurs, then the Crew will at least have a starting point to isolate the problem.

On a side note, The GPS II+ still works fine at 320 Kts, not bad for something designed for a 4WD (and not many can go that quick)

I used to use a Lowrance GPS200 in the C130 (coupled to a Psion 5 running Sierra flight planning software) before we got GPS/IRS installed, and it quite happily coped - and this was sold as a fisherman's navaid in deepest Northern Canada. In fact, it was a bloody good combination, with all the functionality of a Litton 92 or FMS (without VNAV), for far less than the cost of your average aviation Garmin.

My GPS12 shows Max speed @ 589mph from a previous jaunt to Norway.

Passengers in my car are always impressed when they look at the display. Not bad for an Escort eh? :)

------------------
Through Difficulties to the Supermarket....

As I have worked in the world of EMC compliance for the last ten years (albeit in consumer audio) I thought I could try help clear a couple of things up. Sorry if I get a bit technical....
CRTs don't emit that much RF radiation, there's not really any fast circuitry in them. Anyway, as mentioned before if they are designed to be fitted inside an aircraft they will be suitably screened and tested. Acually X rays are more of a problem with CRTs.

FCC Class B is an RF radiated emissions class. Essentially you go to an open area test site, wave a calibrated antenna at the product at a calibrated distance and measure the RF emissions. If they fall below a certain limit the product passes. Class B means a product can be used in a residential environment. Class A is industrial (an aircraft environment is not mentioned and the FCC did not take avionics into account when they set the limits). An FCC Class B label can mean a) a genuine product has been tested by an approved test lab and the product has passed the test or b) a specially made "get through the FCC test" product has been made and tested or c) the product has not been tested as it would never pass and the manufacturer is lying. I am afraid there are thousands of b) and c) type products in the market.

Power consumption level and whether AC or DC has little to do with RF emissions, it is the type of circuit contained within a device that counts. An analogue tape recorder has only a low frequency bias oscillator. A CD or Minidisc player has all sorts of high frequency oscillators, to work the micro processor and digital to analogue convertor etc, inside it. These oscillators use square shaped waveforms which are bad as far as EMC is concerned as they produce harmonics of the fundamental frequency which can radiate up to the GHz region. Also, these devices are very compact which limits the amount of EMC supression components that can be fitted.

The only way to make a device truly immune to all EMC interference is to completely seal it in a metal box. However you need to get power, interface cables, an antenna etc to it, it may need ventilation. You can filter these ports but not 100%. You can test devices for immunity but not for every conceivable circumstance.

Call me old fashioned but if I were the captain of an aircraft I would not allow passenger electronic equipment to be switched on at any stage of a trip.

Don

Just to make a point, to whoever pointed out that Hugmonster has 4 stripes and is threatening things, (which I don't see he is), the fact that he has 4 stripes means that he is in command and has the power to throw the police off his aircraft, doesn't this mean he is the authority??

This obviously applies to all, and if I was told not to use a GPS after being told not to by such an authority, and I did, then I would gladly take what was coming to me, I agree,

"pathetic"

Rusty (in one of those moods)
:) :)

DDC, a good post and useful background info, thanks. Now, can you (or anyone else out there) extend this and apply it to GPS units?
:)

Overfly,

You may have missed the point in all this mate.

As a GPS unit, your GPS may do nothing to the aircraft - but as a piece of eletronics - it may have the potential to do so [no matter how remote]. DCC [& others in this thread] appear to provide authoritative info for you

Like you aqnd others, I have used a hand held GPS [as a fast jet QFI 'cheating' on those low level tac navexs], and yes nothing happened - But I was Aircraft Captain, I knew it was operating, and I am aware of what EMF can do, AND as I was the primary Nav instrument, any interference to any other bits of kit [limited in a FJ trainer!] was minimised.

Those hand held units may not be a problem, but until someone qualified to SAY SO, actually SAYS SO, [and specifies aircraft type etc.], we in the aviation community must consider the consequences.

Further, at the end of the day - The Aircraft Captain IS THE AUTHORITY. If you don't like this then become one and discover the responsibility.

Enjoy those buttons on your nav kit.