A New GPS Question

[LettersFromFlyoverCountry]

Originally Posted by OldAndBold

So why do they tell us not to use our electronic devices during flight? Control. Must control passengers. Passengers bad, Airline staff good.
--JCB

I flew into MSP a few weeks ago from Boston on the morning of a blizzard and we got as far as about 100 feet from the jetway. And we sat. Finally a guy in a seat a few rows up pulls out his laptop and starts working.

The stewardess, errr, flight attendant, goes nuts and tells him to shut it off "because we're not at the gate yet."

I shudder just to think of how close we came to dying that day.

[Jamie]

My biggest pet peeve w/ flight attendant electronic instructions? "OFF" is not a position.

I'm VERY glad to see that the FCC is still nixing the idea of cells on commercial aircraft.

[Kevin Horton]

Originally Posted by OldAndBold

Consider an airliner on approach to ORD. Consider how many sources of RF energy are impinging upon the aircraft at that delicate electronic moment. It is about 15 miles line of sight from Sears Tower which has most if not all of Chicago's TV transmitters - that is literally megawatts of effective radiated power.

Also consider that all there is an aluminum skin between all these external radiation sources and the avionics and wiring. The aluminum fuselage acts like a Faraday cage, providing a significant amount of protection to the avionics. But your personal electronic device (PED) is inside the fuselage, and much, much closer to the avionics and wiring.

If the avionics and wiring, etc are properly designed and installed, and there are no flaws in the shielding etc, there is very little risk of a problem from a PED that have passed the normal FCC tests. But, consider that a certain percentage of aircraft will have bad coax, bad wiring, etc. And a certain percentage of PEDs may have been improperly assembled, or they may have been dropped, which could shift the internal shielding. If the bad PED is in a location that is close to the flaw in the aircraft's shielding, then it is possible to have a problem.

Several years ago I spoke with the captain of a Challenger business jet who told me an interesting story. They were in cruise, when suddenly the VOR indications in the cockpit started doing very strange things. He sent the copilot back in the cabin to see if anyone was using a PED. He found that the CEO's son was playing with a Game Boy. The Game Boy was turned OFF, and the VOR indications returned to normal. The Game Boy was turned back ON, and the VOR problems returned. Game Boy OFF for the rest of the flight.

The problem is real, but it takes specific circumstances to allow it to happen. In cruise, the consequences are low enough that it makes sense to allow the use of PEDs. At low altitude, the potential consequences are a fatal accident, so it makes sense to prohibit use of PEDs.

[OldAndBold]

Originally Posted by Kevin Horton

Also consider that all there is an aluminum skin between all these external radiation sources and the avionics and wiring. The aluminum fuselage acts like a Faraday cage, providing a significant amount of protection to the avionics
. . .
The problem is real, but it takes specific circumstances to allow it to happen. In cruise, the consequences are low enough that it makes sense to allow the use of PEDs. At low altitude, the potential consequences are a fatal accident, so it makes sense to prohibit use of PEDs.

Actually, I wasn't suggesting the operation of PEDs during approach. Just pointing out that the airplane is exposed to far more EMI from outside than anything that is inside. Your comment about the effects of the fuselage is valid though. Nonetheless the antennas are all outside and exposed to all that EMI. And after all, the thing we are talking about operating during flight (a GPS receiver) is specifically intended to be operating onboard an airplane(!)

I hate flying on airliners. Hate it hate it hate it. I will drive 800 miles to avoid using an airline. It will be interesting to see how far I will be willing to fly the RV to avoid the airlines - I suspect the decision will have much more to do with avoiding flight over the Rockies or whether the flight is out of the country.

--JCB

[the_other_dougreeves]

Originally Posted by OldAndBold

I hate flying on airliners. Hate it hate it hate it. I will drive 800 miles to avoid using an airline. It will be interesting to see how far I will be willing to fly the RV to avoid the airlines - I suspect the decision will have much more to do with avoiding flight over the Rockies or whether the flight is out of the country.

I've somehow turned into one of those road warriors who travels every week. Luckily for me, it's an easy flight, lots of direct service, DFW-SNA. However, flying anything short of a turboprop (ok, maybe a Malibu or P210) just isn't going to work - too much weather, terrain and plain distance between here and there.

And so I have developed this love/hate relationship with American Airlines. I love that they get me across two time zones and a lot of mountains in less than three hours. I love that I'm whatever Super Grand PooBah status to where I get to select exit row seats ahead of time and sit with extra legroom and a power port for the laptop (somehow, the airplane is the only time I get to watch movies. I sure can't work when we encounter moderate turbulence, but watching movies is easy ).

I hate that even 737s can't deal with mesoscale complex thunderstorms like we got last week and I get delayed. I hate having to go to DFW and suffer the indignities of the TSA. But most of all, I hate that I'm out of town when my airplane sits in the hangar, doing nothing. As my wife mentioned to my father-in-law one day "No, the little airplane isn't the problem. It's the big airplane that's the problem."

Anyway, I've never tried to use a GPS as self loading cargo - er, pax. What I frequently do is take along WAC charts to try and navigate VFR in the flight levels. It's actually a pretty educational experience. Who else does this?

[OldAndBold]

Originally Posted by the_other_dougreeves

. . .
Anyway, I've never tried to use a GPS as self loading cargo - er, pax. What I frequently do is take along WAC charts to try and navigate VFR in the flight levels. It's actually a pretty educational experience. Who else does this?

When I was a student pilot I would take the VFR sectional with me and try to follow the flight from Yuma back to LA. Got lots of dopey looks and remarks from fellow passengers. I flew a lot in and out of the SF Bay area for a while and I got to a point where I could generally know exactly where I was anytime after the airliner cleared the Sierra Nevadas or got north of about Morro Bay - I could figure which town was which, where the airports were and figure out which approach the pilot was taking. They'd put flaps out as they went over Livermore on an approach to Oakland, or on the way into SJC I'd know whether they would be landing from the north or the south. Or into SFO I'd recognize all the little airports on the way up the shoreline.

What really bugged me though was flying over Tracy and being able to spot my house - and knowing that as I flew over it that because of time spent at the airport and traffic and the commute home it would be another three to four hours before I would be walking in the front door!

Geez I miss flying in CA...

[lucaberta]

Originally Posted by Kevin Horton

Several years ago I spoke with the captain of a Challenger business jet who told me an interesting story. They were in cruise, when suddenly the VOR indications in the cockpit started doing very strange things. He sent the copilot back in the cabin to see if anyone was using a PED. He found that the CEO's son was playing with a Game Boy. The Game Boy was turned OFF, and the VOR indications returned to normal. The Game Boy was turned back ON, and the VOR problems returned. Game Boy OFF for the rest of the flight.

similar experience that a friend of mine at Alitalia had a few years ago, when he was F/O on the MD11. He now is an MD80 Captain, and has also been building his RV-8 for some 5 years now, hopefully this summer is the right one!

Humming over the ocean in the NAT tracks at night, the fuel computer all of a sudden starts to move fuel from one wing to the other for no apparent reason (the MD11 has a fuel computer that *tries* to keep the best CG and balance for the plane at any given time). The fuel keeps on moving, and then the plane really starts to be unbalanced... flight attendand told to go check for PEDs, kid playing a Gameboy found, Gameboy switched off, fuel computer stops pumping fuel, realizes that the plane is now *really* unabalanced, and starts pumping the fuel back in the right tank... kid told to switch it on again, fuel computer gets confused again, so Gameboy off again.

So they have the kid moved a few rows to another empty seat, Gameboy goes on and nothing happens to the fuel computer...

After this story, I keep very careful control of my actions on PEDs in flight... this stuff happens for real, unfortunately!

Ciao, Luca