Menu Sign In Contact FAQ
Banner
Welcome to our forums

Is IFR with a single GPS (or single radio) legal?

One of the COMs could fail.

Yet, there is no requirement for duplication of radios – unless required by some STC.

On the general approach:

If, if, if… There is a saying in Czech, which doesn’t rhyme in English, along the lines of “if there were no fish in the pond, they might be in your ar*se”

This is quite a puritanical approach, because in a typical SEP you are much more likely to lose the alternator (which is a crappy unit from a 1960s Ford truck but selling for $1000 with basically worthless “traceability paperwork” to keep the regulators happy) and the battery will go flat fairly soon afterwards.

So a risk assessment which leads to two panel mounted units (when actually a handheld GPS of some sort would be the logical nav backup; a VOR receiver is farcical nowadays in Europe) in order for an STC to be approved, is largely an artificial exercise where all the old chums in the regulatory business support each other

But they can’t allow a handheld backup because handheld stuff is not TSOd/ETSOd so no bread on the table at home of the regulator.

I see this at work with the old scam called ISO9000. It means absolutely zero, zilch, nowt, nothing whatsoever regards the quality of the actual product.

I remember a CAA presentation where the CAA said (regarding GPS) that they asked the FAA if they ever did a calculation of the reliability of GPS and the FAA replied “no”. This is obviously BS in a number of ways. But this is how the regulatory process works.

Administrator
Shoreham EGKA, United Kingdom

arj1 wrote:

I’m not sure how could you fly with a single VHF COM on G1000 – under IFR the G1000 field installation manual explicitly demands for two GIA63 modules (and the minimum equipemnt checklist before the IFR flight). Each of them contains one VHF COM radio. You would have to disconnect one antenna?

One of the COMs could fail.

Also, the C172S POH Limitations Section I referred to doesn’t even explicitly require both GIA63 to be operational for IFR – but of course on such an aircraft you can’t meet the part-NCO requirement for backup nav with a single GIA63 so it would be a no-go for that reason.

ESKC (Uppsala/Sundbro), Sweden

Airborne_Again wrote:

Ibra wrote: You do need two radios for IFR with G1000 !!

That’s at least not the case for a Cessna 172S with factory-installed G1000. The Limitations Section of the POH clearly states “VHF COM: 1” for IFR.

@Ibra, I’m not sure how could you fly with a single VHF COM on G1000 – under IFR the G1000 field installation manual explicitly demands for two GIA63 modules (and the minimum equipemnt checklist before the IFR flight). Each of them contains one VHF COM radio. You would have to disconnect one antenna?

EGTR

Ibra wrote:

You do need two radios for IFR with G1000 !!

That’s at least not the case for a Cessna 172S with factory-installed G1000. The Limitations Section of the POH clearly states “VHF COM: 1” for IFR.

ESKC (Uppsala/Sundbro), Sweden

That’s probably dealt with by Cobalt above. Somebody got a G1000 STC and the approval authority demanded two radios. And everybody with a G1000 installed under that STC is stuck with that requirement.

It doesn’t mean anything re legality of IFR with one radio, in European airspace.

Administrator
Shoreham EGKA, United Kingdom

Interesting that the requirement for a “backup nav” does not exist for comms. You don’t need two radios.

You do need two radios for IFR with G1000 !!

I see my post on that was removed…

Last Edited by Ibra at 25 Nov 16:51
Paris/Essex, France/UK, United Kingdom

That’s clear enough – probably because it was written by Bookworm who is a real pilot

Interesting that the requirement for a “backup nav” does not exist for comms. You don’t need two radios.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

I give up! This gets 10/10 for jumbled-up semantics.

Well, sorry. I sometimes try to put things in concise everyday terms rather than quoting regulations in all their nitty-gritty details. Maybe I should keep to doing that? Here are the relevant regs:

NCO.IDE.A.195 Navigation equipment
(a) Aeroplanes operated over routes that cannot be navigated by reference to visual landmarks shall be equipped with any navigation equipment necessary to enable them to proceed in accordance with:
..(1) the ATS flight plan; if applicable; and
..(2) the applicable airspace requirements.
(b) Aeroplanes shall have sufficient navigation equipment to ensure that, in the event of the failure of one item of equipment at any stage of the flight, the remaining equipment shall allow safe navigation in accordance with (a), or an appropriate contingency action, to be completed safely

AMC1 NCO.IDE.A.195(b) Navigation equipment
APPROPRIATE CONTINGENCY ACTION
An appropriate contingency action is an alternative offered in NCO.IDE.A.195(b) to completion of the planned flight to a safe landing, either at the planned destination or a destination alternate, using normal procedures and using navigation equipment meeting the requirements of NCO.IDE.A.100, installed for redundancy or as a backup.
The contingency action should be considered before flight and take into account the information identified by flight preparation according to NCO.OP.135. It may depend on the flight and availability of navigation solutions (satellites, ground navaids, etc.) and weather conditions (IMC, VMC) along the flight.
The contingency action addresses partial loss of navigation capability. An appropriate contingency action to meet the requirements of NCO.IDE.A.195(b) does not rely on the performance of any function of the item of equipment whose potential failure is being considered. For example, in considering the failure of a VOR/LOC/DME receiver, none of the functions of that receiver should be relied upon in the contingency action.
Examples of contingency actions include:
— seeking navigational assistance from ATS, using communication, navigation and surveillance systems that remain operational, to enable a safe instrument approach or a safe descent to VMC;
— unusually long periods of dead reckoning.
A contingency action is required such that the failure of one item of navigation equipment has a reasonable likelihood of a safe outcome to the flight, consistent with other risks to which the operation is exposed.

Last Edited by Airborne_Again at 25 Nov 16:20
ESKC (Uppsala/Sundbro), Sweden

The main problem here is that authorities feel the need to bake current rules into STCs. Then the rules change because reality changes, but the old STCs remain effective and freeze long-outdated rules. And the cost to change the STC is prohibitive.

Arguably nothing about alternative equipment should be in wigglyamp’s STC, only things that relate to the safe operation of the installed equipment.

Biggin Hill

Airborne_Again wrote:

I certainly did not say that you can do with no back-up equipment!
Avionics geek.
Somewhere remote in Devon, UK.
71 Posts
Sign in to add your message

Back to Top