FAR Question - Approval Basis for Handheld GPS

kontiki

kontiki

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Kontiki
All,

I've been wondering how folks interpret FARs with regard to handheld GPS devices.

14CFR91.21 says except as provided . . . no one can operate a portable electronic device while under IFR.

I bought my aera 510 thinking that it would be a good way to obtain weather while flying IFR in an otherwise well equipped w/GPS, rental AC.

It occured to me the 510 could be considered a class 3 EFB device, or a PED and that as provided in 91.21, I as an operator I could claim that I determined it didn't interfere electrically, based on chicken bones or something.

So, how do folks rationalize through the regs to use Garmins and IPADS on an IFR flight?

Thanks,
 
the answer starts with something like, "...advisory only"
 
kontiki said:
14CFR91.21 says except as provided . . . no one can operate a portable electronic device while under IFR.
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You need to read the whole thing.

§ 91.21 Portable electronic devices.

(a) Except as provided in paragraph (b) of this section, no person may operate, nor may any operator or pilot in command of an aircraft allow the operation of, any portable electronic device on any of the following U.S.-registered civil aircraft:

(1) Aircraft operated by a holder of an air carrier operating certificate or an operating certificate; or

(2) Any other aircraft while it is operated under IFR.

(b) Paragraph (a) of this section does not apply to—

(1) Portable voice recorders;

(2) Hearing aids;

(3) Heart pacemakers;

(4) Electric shavers; or

(5) Any other portable electronic device that the operator of the aircraft has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used.

(c) In the case of an aircraft operated by a holder of an air carrier operating certificate or an operating certificate, the determination required by paragraph (b)(5) of this section shall be made by that operator of the aircraft on which the particular device is to be used. In the case of other aircraft, the determination may be made by the pilot in command or other operator of the aircraft.
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iNdigo,

Thanks, youre right, I didn't read the last sentence of (c). That's enough for me.
 
yep - the pilot gets to decide if the PED is ok.

How many pilots are actually qualified to determine if the PED can cause interference?

[edit: by "qualified" I mean capable. I don't mean to imply there is some certification or approval needed)
 
Why in the world would an electric shaver be an exemption. I say BAN EM'
 
Bob Noel said:
yep - the pilot gets to decide if the PED is ok.

How many pilots are actually qualified to determine if the PED can cause interference?
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I read the little statement that says "this device won't cause interference, but must accept any from other devices" :D
 
Bob Noel said:
yep - the pilot gets to decide if the PED is ok.

How many pilots are actually qualified to determine if the PED can cause interference?

[edit: by "qualified" I mean capable. I don't mean to imply there is some certification or approval needed)
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Just consider this being another one of those cases where the FAA's multiple levls of safety policy works in our favor and let it quietly go. In this particular case, their response to some of the outcry regarding the new version of AC 120-76 reinforced their commitment to letting us take care of ourselves regarding PED's.
 
I'm actually kind of handicapped on this subject because of a personal interest and a couple good seminars on electrical emissions testing.

Most folks didn't make it to the IEEE EMI fest when it was held in ATL 4-5 years ago. I loved it, even bought they guys text book, . . later, . . . used, . . on Amazon. He was good though.

For while, when SFAR88 was first announced, the airline I was working for had me evaluating commercially available software for modeling electrical and magnetic fields and how they might couple across wiring in a commercial airplane.

In fact that airline got NASA money to work with their PhD to do PEDS susceptibility testing on commercial airplanes. One of my associates worked the project. One of the things they would do is transmit signals outside the hull (various frequencies) and map the signal strengthens at each window and aisle seat for different polarities.

Really interesting stuff, but very tedious to do. Result was no change in PEDS policy for passengers. No smoking guns though.
 
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kontiki said:
I'm actually kind of handicapped on this subject because of a personal interest and a couple good seminars on electrical emissions testing.

Most folks didn't make it to the IEEE EMI fest when it was held in ATL 4-5 years ago. I loved it, even bought they guys text book, . . later, . . . used, . . on Amazon. He was good though.

For while, when SFAR88 was first announced, the airline I was working for had me evaluating commercially available software for modeling electrical and magnetic fields and how they might couple across wiring in a commercial airplane.

In fact that airline got NASA money to work with their PhD to do PEDS susceptibility testing on commercial airplanes. One of my associates worked the project. One of the things they would do is transmit signals outside the hull (various frequencies) and map the signal strengthens at each window and aisle seat for different polarities.

Really interesting stuff, but very tedious to do. Result was no change in PEDS policy for passengers. No smoking guns though.
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When they did that testing, were only correctly functioning units used? Was any testing done with out-of-spec units that still appeared to be working?
 
One of the guys at AirVenture was recommending that to dot the 'i's and cross the 't's that you carry a statement with you that you have, in your capacity as PIC, evaluated the device and found that it does not cause interference. Just write it on the scratchpad in Foreflight, sign it there, and save the screen image. :)
 
When the tests involved actual PEDS (vs. trying to characterize transmission pathways and leakage characteristics) they got boxes of the unclaimed electrical stuff folks left in the airplanes and used them. So it was a real sample of "as is" gear.
 
Everskyward said:
You've never seen your battery-powered watch cause interference have you? There, you made the determination.
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I'm not allowed to make the determination when I'm a passenger. On my airline flights within the past two weeks, the airline's instructions to turn off electronic devices made no exception for watches.
 
Palmpilot said:
I'm not allowed to make the determination when I'm a passenger. On my airline flights within the past two weeks, the airline's instructions to turn off electronic devices made no exception for watches.
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Did the flight attendant come around and lecture you about your watch? If not you are fine...
 
Palmpilot said:
I'm not allowed to make the determination when I'm a passenger. On my airline flights within the past two weeks, the airline's instructions to turn off electronic devices made no exception for watches.
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Anybody know where the official FAA definition of a PED is (can't find it in 91.21 or 1.1), and whether or not it includes watches? IIRC, the FCC makes everyone put that little sticker on anything which radiates, and you don't see those on wrist watches.
 
You could try looking in Advisory Circular AC 91.21-1B. Use of Portable Electronic Devices Aboard Aircraft

On the way out of the office today, I ran into the guy that worked with the NASA contractor doing the study (the entire work group bailed on that airline to where we are now).

I asked him if there was a final report on the work they did. It wound up as an RTCA document. That's sad, because there is no legal way to share it publicly, they are fanatic about copy write protection.

It's available from the RTCA site for a fairly hefty fee.
 
kontiki said:

I asked him if there was a final report on the work they did. It wound up as an RTCA document. That's sad, because there is no legal way to share it publicly, they are fanatic about copy write protection.

It's available from the RTCA site for a fairly hefty fee.
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Do you happen to know the doc number or does it have an obvious title?
 
Ron Levy said:
Anybody know where the official FAA definition of a PED is (can't find it in 91.21 or 1.1), and whether or not it includes watches?
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I doubt that there is an FAA definition of the term, and if not, then I think we're stuck with the dictionary definitions of the words.

IIRC, the FCC makes everyone put that little sticker on anything which radiates, and you don't see those on wrist watches.
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Everything that has alternating current flowing in it radiates to some degree, but not everything that meets that description has an FCC sticker on it.

This is not a serious concern to me, by the way. I just think it's an amusing oversight in the exceptions list. I can just see a planeload of airline pax trying to figure out how to remove the batteries from their watches!

Or maybe I should go back and delete my post; I wouldn't want to give a rogue FAA inspector ideas!
 
Scratch that alternating current only thought. Plenty of DC-only stuff that radiates into the Spectrum somewhere.

Pulsed DC can be just as noisy as AC powered stuff.

Heck even I radiate, and I'm all DC powered...

But most of my radiation is in the infrared spectrum where it rarely bothers aircraft avionics. ;)
 
denverpilot said:
Scratch that alternating current only thought. Plenty of DC-only stuff that radiates into the Spectrum somewhere.

Pulsed DC can be just as noisy as AC powered stuff.

Heck even I radiate, and I'm all DC powered...

But most of my radiation is in the infrared spectrum where it rarely bothers aircraft avionics. ;)
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Pulsed DC has AC components in it. I don't know what the mechanism would be for pure DC to radiate at radio frequencies.

As for infrared, I wasn't aware that the FCC regulated that part of the E/M spectrum.
 
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Heh. They are working hard right now to figure out how to auction it off for billions, I'm sure. ;)
 
Bob, My buddy couldn't remember it off hand. The RTCA online store has an online list of all documents for sale.

The Topical index lists:

PORTABLE ELECTRONIC DEVICES (PEDs)

DO-307 Aircraft Design and Certification for Portable Electronic Device (PED) Tolerance
Issued 10-11-07 · Prepared by SC-202

Change 1 to DO-307
Issued 12-16-08

DO-294C Guidance on Allowing Transmitting Portable Electronic Devices (T-PEDs) on Aircraft
Issued 12-16-08 · Prepared by SC-202

DO-233 Portable Electronic Devices Carried on Board Aircraft
Issued 8-20-96 s Prepared by SC-177 s Errata Issued 8-18-99

DO-199 Potential Interference to Aircraft Electronic Equipment from Devices Carried Aboard
Issued 9-16-88 s Prepared by SC-156 s Supersedes DO-119

The work I saw was complete by around 2002-3. To be honest, nothing listed here looks to me like it would be it. Maybe my buddy misspoke. I know for me after a few years goes by, event details in all of this technical regulatory stuff really gets blurry.

On the record for the company, I say nothing without double/tripple checking first. To an outsider, I'm sure it looks like I have some kind of compulsive disorder. Human memory is just lossy.
 
Just for the record, my thumbnail sketch for remembering areas of susceptibility on a very high level, electrical noise couples through:

RF (radiated) - high frequencies, low current, wavelength approaches length of conductor

Electrical Field (capacitive coupling - parallel wires) lower frequencies low current, so much capacitance per foot, at x ft you get cross talk.

Magnetic Field - low frequency, high current, like in a transformer. Ever watch the 28VDC ground power unit wires jump when engine start button is pressed?

Direct transmission, ohmic or capacitive common mode noise back through power supplies, or when current runs through high resistances in ground plane.

Also, if you look at the spectral model for a single idealized digital pulse, it has infinite bandwidth (is built from sum of sinusoid signals containing all frequencies).

You can electrically generate build a DC pulse train by summing 3rd harmonic of a sine wave. It's a typical college lab project, I remember doing this, (from memory) X Hz at Amplitude of 1 plus 3X Hz with amplitude 1/3 plus 9X Hz at amplitude of 1/9 and so on and so on. Maybe sum them through an OP amp that has with no unusual characteristics at those frequencies and you have it.

Therein lies the problem with evaluating the safety for yourself, If you successfully maintain separation from obstacles flying IFR in IMC, your portable uncertified XM weather or collision avoidance device probably didn't affect your nav gear.

I will say, after participating in a number of STC efforts over the years, I don't really believe the EMI tests and evaluations required as part of that process are in any way bullet proof. The environment is too complex.

I believe the EMI protection we all take for granted works because of a multi-layered approach, and relying heavily on emissions standards and maybe susceptibility standards that affect all electrical devices sold in the US (FCC Chapter 15) or Europe (CE) or TSO certified (RTCA DO-160) etc. The list of emission/susceptibility specs goes on and on. No one can sell any electrical device without building in emissions control and maybe susceptibility control.

The FCC lets the consumer market control susceptibility (sales drop if it's affected), CE enforces it. FCC monitors compliance, CE uses self disclosure (honor system), but if the companies lie, the individuals that signed the disclosure can be held legally responsible. This includes power drills, toothbrush, watches etc.

No more typing - it's Saturday!
 
kontiki said:
You could try looking in Advisory Circular AC 91.21-1B. Use of Portable Electronic Devices Aboard Aircraft
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Just did -- no definition there I could find. In any event, unless your wristwatch includes a GPS or a Dick Tracy video phone device or the like, I don't think anyone will be telling you to turn it off on an airline flight.

"6, 2, and even -- over and out."
 
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Ron,

I had a copy of RTCA DO-294A Guidance on Allowing Transmitting Portable Electronic Devices (T-PEDs) on Aircraft in the office.

I cannot in any way copy you on it. It would be to stupid to break trust with my employer over something like this, I just have too good of a job.

I did do string search and it didn't present any sort of definition, aside from breaking down the acronym. There are PEDs and T-PEDs, the second stands for transmitting portable electronic devices. This document is about 380 pages and it does look like it might be the report resulting from the study.

Actually, it looks like very interesting reading. I wish I wasn't already up to my eyeballs in unread books to begin with.
 
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Ron Levy said:
In any event, unless your wristwatch includes a GPS or a Dick Tracy video phone device or the like, I don't think anyone will be telling you to turn it off on an airline flight.
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Agreed. The only reason I brought it up was I thought it was amusing.

An Internet search reveals that wristwatches are subject to emissions testing under FCC Part 15 if they contain clocks/oscillators which operate at a frequency above 9kHz, but they are apparently exempt from testing in Europe.

http://www.pseinc.com/faq.htm

http://www.ce-mag.com/99ARG/GubishBjroklof73.html
 
Ron Levy said:
So, does anyone know how many watches contain such an oscillator?
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I don't think it's possible to buy a battery powered watch that doesn't have an oscillator, and since 9 kHz is quite a low frequency, my guess would be that all of them would fall within the FCC requirement.

This place sells crystals, and all of the ones that are labeled as watch crystals are 32.768 kHz.

http://frequencymanagement.com/crystals.html
 
In that case they should be subject to FCC testing and thus not a threat -- one would think. In any event, I don't see any airlines telling passengers to turn off their wristwatches.
 
Ron Levy said:
In any event, I don't see any airlines telling passengers to turn off their wristwatches.
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Well, on most of my flights, the flight attendent instructs us to turn off our electronics, anything with an on-off switch. If your watch has an on-off switch...
 
Ron Levy said:
Anybody know where the official FAA definition of a PED is (can't find it in 91.21 or 1.1), and whether or not it includes watches?
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Your question reminds me of this cartoon:

Bizarro-07-31-11-WEB.jpg
 
Ron Levy said:
In that case they should be subject to FCC testing and thus not a threat -- one would think.
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FCC Part 15 compliance is not a guarantee that they won't be a problem on airliners. Pretty much all PEDs are subject to Part 15 requirements, but some of them are still reported as causing interference to avionics.

Part 15 covers use in the home or industrial environments, not around sensitive avionics receivers. There's also no guarantee that a PED that passed FCC requirements when new would still pass in its current condition.

My guess is that the reason electronic watches haven't been a problem is because the power level is so low.

In any event, I don't see any airlines telling passengers to turn off their wristwatches.
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Me neither. Maybe they've made a determination that they don't cause interference as required in 91.21.
 
Bob Noel said:
Well, on most of my flights, the flight attendent instructs us to turn off our electronics, anything with an on-off switch. If your watch has an on-off switch...
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On my flights in the past couple of weeks, they didn't say anything about on-off switches, so the terminology is apparently not uniform.
 
On many devices, selecting the OFF mode does not disable the internal clock anyway. Obviously, there is an internal oscillator of some type always running.
 
Palmpilot said:
I notice there's no exception for battery-powered watches.
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Generally any device where the highest clock frequency is 32 kHz or less is considered to be incapable of generating interference. Not so coincidentally that's the frequency used by most electronic watches.
 
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