Unbeliever
Pre-takeoff checklist
No. That was 85Q's GX-55. *grin* That was a bad antenna placement on that one. It was up against the dorsal fin which blanked out half the sky. 4FH's GX-50 just reboots on you.
--Carlos V.
Hand held GPS
- Thread starter Tom-D
- Start date
No. That was 85Q's GX-55. *grin* That was a bad antenna placement on that one. It was up against the dorsal fin which blanked out half the sky. 4FH's GX-50 just reboots on you.
--Carlos V.
Areeda
Pattern Altitude
You people keep ruining my stories with all these facts
You're right Carlos it was 85Q.
Joe
Unbeliever
Pre-takeoff checklist
You people keep ruining my stories with all these facts
Sorry, it's a personality disorder.
One of the many reasons why I'm still single *grin*
--Carlos V.
flyingcheesehead
Taxi to Parking
Heh... I saved my maximum speed on my old Street Pilot 2620: 2,795 mph. Showed it to the safety director at the company just to give him a good laugh...
nyoung
Pre-takeoff checklist
Yes and No.
Yes: I have worked with GPS systems since 1993, and they are tremendously reliable. I have also been a pilot since 1994. During the 1100 hrs since then, I have had my NAVCOM fail twice. My handheld GPS has failed once. During the time it failed, it placed a nice X on the nav screen to let me know it had failed. Furthermore, when active... GPS is much more precise than a VOR approach, and pretty close to an ILS approach. Moving map GPSs also provide situational awareness that makes following an OBS needle seem like an exercise in futility.
I realize that a handheld GPS does not have RAIM. But RAIM or not, it is still more reliable and precise than a VOR. Having said that, given a choice between an ILS and a non precision GPS approach, I would prefer the ILS.
No: A GPS receiver is only as good as the antenna installation. I have used the remote GPS antenna, suction cupped to the windshield (in a Cherokee) and had wonderful results (99.99 uptime). I have also tried using the Gumstick GPS antenna that comes with the Garmin 295/6, 396, 496. It works pretty well, but often the line of sight to the satellite is broken by the dash (if yoke mounted) or the cabin (if placing the GPS on the passenger seat).
So, IMHO, the FAA should consider allowing handheld GPSs to be used for non precision approaches... IF, they have a remote antenna installed by a mechanic.
Yes: I have worked with GPS systems since 1993, and they are tremendously reliable. I have also been a pilot since 1994. During the 1100 hrs since then, I have had my NAVCOM fail twice. My handheld GPS has failed once. During the time it failed, it placed a nice X on the nav screen to let me know it had failed. Furthermore, when active... GPS is much more precise than a VOR approach, and pretty close to an ILS approach. Moving map GPSs also provide situational awareness that makes following an OBS needle seem like an exercise in futility.
I realize that a handheld GPS does not have RAIM. But RAIM or not, it is still more reliable and precise than a VOR. Having said that, given a choice between an ILS and a non precision GPS approach, I would prefer the ILS.
No: A GPS receiver is only as good as the antenna installation. I have used the remote GPS antenna, suction cupped to the windshield (in a Cherokee) and had wonderful results (99.99 uptime). I have also tried using the Gumstick GPS antenna that comes with the Garmin 295/6, 396, 496. It works pretty well, but often the line of sight to the satellite is broken by the dash (if yoke mounted) or the cabin (if placing the GPS on the passenger seat).
So, IMHO, the FAA should consider allowing handheld GPSs to be used for non precision approaches... IF, they have a remote antenna installed by a mechanic.
gismo
Touchdown! Greaser!
I think we can all agree that GPS can be very reliable. But from the regulator's perspective there are two things missing. One is some set of standards that must be met, without this, a GPS made by a couple of hacks in a remote corner of India (actual location/country picked at random) would be acceptable even though it might be no more reliable or accurate for navigation than a divining rod. The other is that the FAA always requires some means of detecting and displaying an erronious guidance indication.
The latter could easily be added by any GPS manufacturer but as I stated earlier, I believe this is because the common practice of using the attached helical antenna inside an aircraft cabin would result in an annoyingly high rate of alarms. But the first issue appears to be a big hurdle. The FAA isn't going to push for this and the existing manufacturers don't seem to be interested in pursuing the adoption of standards for IFR handheld GPS. I assume the reasons for that are liability concerns and in some cases fear of self competition with the company's own panel mounted IFR GPS models.
jtheune
Ejection Handle Pulled
1. Every handheld GPS I've seen indicates when it's lost position.
2. If the FAA thought the need to indicate a errous position then why have they not banned CDIs that don't flag?
gismo
Touchdown! Greaser!
They do indicate when insufficient satellites are being received to generate a solution but they don't indicate when the solution is in error.
Actually, they have in that the TSO for CDIs and VOR receivers requires that the display "flags" when the signal strength is too weak to generate an accurate indication. There are, of course many potential failure modes that can go undetected with VOR navigation but they have always required some means of detecting an invalid solution for all IFR approved GPS devices and I don't see them recinding this requirement for IFR handhelds if any ever appear on the market.
John Collins
En-Route
Lance,
I agree and not only will the FAA not push for it, they would actively oppose it. Furthermore, as you pointed out, the manufacturers have absolutely no interest in providing a hand held GPS that could be used for IFR enroute, terminal, or approaches. The hand held is a valuable tool for situational awareness and as an emergency backup.
Normally, manufacturers and other interested parties use an organization such as RTCA to develop a standard that is often adopted as the technical specification for a TSO. The RTCA standard DO-229D is the current standard for "Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System, Airborne Equipment" adopted by RTCA and referred to in the TSO-C146a for WAAS GPS. RTCA DO-208 is the standard that has the details for the "Minimum Operational Performance Standards for Airborne Supplemental Navigation Equipment using Global Positioning System"
There is no RTCA work group or request for a work group to develop a specification for a portable GPS receiver. To think there ever will be is a total waste of time and very naive. A specification for a warp drive is much more likely to come about.
gismo
Touchdown! Greaser!
Oooh, do you think there's any chance for a STC that includes my Baron?
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Bob Noel
Forgive me, but back in the late 1990's, I heard (from what I feel is a reliable source) that the FAA actually floated the idea of an AC for approval of handheld GPS'. None of the manufacturers were interested and the idea died.
ScottM
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iBazinga!
Could be. It has been my experience when such things happen is that the requirements for those approvals are far from what the market can support from a unit pricing perspective and more improtantly from a user requirments point of view.
For non commercial ops, sure.
Anthony
Touchdown! Greaser!
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Anthony
X2. I think this is appropriate.
I think the current "don't ask, don't tell" world keeps the handheld price point right for relatively responsible aviators to "use all available means".
Tom-D
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Tom-D
Common sense tells us their top end high priced units would be worth a lot less. No wonder they didn't like the idea
gismo
Touchdown! Greaser!
That doesn't explain why Lowrance or Magellan didn't go for it, they don't have any IFR business to lose AFaIK.
rottydaddy
En-Route
If it's unsafe for commercial flights, it's unsafe for non-commercial flights... right? And they both share the same airspaces, airways, and terminal areas... if a flight using a hand-held is not where it says they are, that commercial flight nearby with a panel-mount is not any safer (unless they have TCAS, I suppose).
Obviously, controllers and pilots have figured out how to work around this, even though these units are for "situational awareness" only under IFR...
Controllers may actually be finding that things on airways and at intersections are a bit more orderly with IFR pilots "misusing" handhelds than they were when everyone had only ground-based navaids and dead reckoning to work with. Wouldn't surprise me.
But... I think very reliable accuracy is pretty damn important in terminal environments, or on any approach or departure, regardless of whether or not it's a revenue flight.
Anthony
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Anthony
No. I was thinking more of regulation, liablility and media perception, not actual safety differences which as you know are meaningless to these issues.
Tom-D
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Tom-D
My hand held is more acurate, easier to use, and has a better screen visability, than the older certified GPS. plus it gives me a host of other features that the others don't.
roncachamp
Final Approach
Do you feel use of a handheld GPS for enroute IFR navigation is unsafe?
jesse
Touchdown! Greaser!
Without standards? Yes. If there were standards, No.
roncachamp
Final Approach
Why? What is the danger?
jesse
Touchdown! Greaser!
Without any standards, what defines a handheld GPS that would be acceptable for enroute navigation? What stops someone from building a total piece of **** and selling it for $35? This $35 POS might drop signal every two minutes and might report completely inaccurate data. The database might be totally inaccurate.
I am not saying that I feel flying enroute with a Garmin 496 would be that dangerous. I'm saying that you can't just open it up to any handheld GPS without some sort of standard.
MauleSkinner
Touchdown! Greaser!
Jumping in late, but I disagree...I think most pilots have very minimal troubleshooting skills, whether it's avionics or aircraft systems, and will tend to believe the most high-tech thing in the airplane (probably the handheld GPS in this case) just because it's the most high-tech thing in the airplane. It's called "automation bias" in FITS documents, I believe.
I've seen it WAY too many times to think it wouldn't happen.
roncachamp
Final Approach
I'm talking about use of a handheld GPS for enroute IFR navigation in US controlled airspace under current rules.
roncachamp
Final Approach
None of that answers the question, "What is the danger?" Apparently you feel there is some hazard in use of a handheld GPS for enroute IFR navigation in US controlled airspace under current rules. Please identify the hazard.
wsuffa
Touchdown! Greaser!
We may have to disagree. To be sure, the pilot population contains folks that are incapable of troubleshooting. And some of the failure modes are insidious. But we also have many very smart, very capable folks in our midst.
It's the same as some pilots run out of fuel, and others are very consiencious.
I look at it the same way as I look at O2 tanks and usage. Portable tanks are just fine, and the FARs don't require built-in O2 for planes flown over the altitude limits. If one extrapolated the GPS rules to O2, we'd be required to have built-in and certified systems anytime we went high.
jesse
Touchdown! Greaser!
If you can't identify the hazard on your own -- I sure won't be able to explain it to you.
People flying around using equipment as primary navigation that isn't certified to any extent and may produce any result has plenty of hazard.
roncachamp
Final Approach
I've examined this issue very thouroughly and have determined it to be nonhazardous. You apparently feel there is some hazard in it but are reluctant to identify it. Why?
If you truly believe that you should be able to identify the hazard. Please do so.
roncachamp
Final Approach
'Zackly. Off airways enroute IFR clearances beyond navaid service volumes can only be had in a radar environment. ATC must provide radar monitoring for all such aircraft, even those with IFR certified GPS. Course guidance must be provided as necessary to aircraft that have not filed /E, /F, /G, or /R. Use of handheld GPS is no more hazardous than being vectored.
I've seen dropouts and strange locations from a hand-held GPS. Some of the dropouts lasted several minutes until I had a good satellite constellation so the GPS could calculate a position again. Somthing blocking the antenna, or reflections inside the plane make getting a position difficult at times.
I remember a flight last year where the VOR needle was centered but the hand-held GPS was showing ~1/4 mile off course. The IFR approved GPS agreed with the VOR (according to the magenta line 'o death). Based on these experiences, I feel the hand-helds are only good as an aid for positional awareness.
An external antenna may have helped but I doubt the FBOs I rent from would let me install one.
I remember a flight last year where the VOR needle was centered but the hand-held GPS was showing ~1/4 mile off course. The IFR approved GPS agreed with the VOR (according to the magenta line 'o death). Based on these experiences, I feel the hand-helds are only good as an aid for positional awareness.
An external antenna may have helped but I doubt the FBOs I rent from would let me install one.
gismo
Touchdown! Greaser!
The biggest hazard I can think of would be navigational errors combined with a loss of communications in the vicinity of obstacles.
Any idea why the hand-held is more accurate besides perhaps having WAAS?
The math to generate a position should work out the same in both units given equal reception of satellites.
The ease-of use and screen visibility will hopefully continue to improve even for certified units.
roncachamp
Final Approach
How does that compare to a loss of communications in the vicinity of obstacles while on radar vectors?
John Collins
En-Route
The accuracy of a hand held may or may not be more accurate than a panel mount, although without WAAS it should be the same or worse than a TSO C129A panel mount due to the panel mount having an external antenna. You can't trust the hand held self proclaimed accuracy figure as these are not standardized and may be more of a marketing value.
With a WAAS hand held, even if the hand held sees less of the sky, it may be more accurate than a TSO C129A panel mount (non WAAS) or worse than a TSO C146A panel mount (WAAS). Of course, if the hand held doesn't see the geostationary WAAS satellites than it might be worse.
The real point is that you can't tell and the hand held does not have any alerting built into it to advise the pilot that the accuracy is out of whack.