IFR certified a/c - required on C of A?

[Finals19]

Question: for an aircraft to be certified for flight under IFR in the UK (assuming also in IMC) does this need to be stipulated on the C of A? I recall reading that the C of A can have a "VFR only" restriction on it. This question relates to a C172.

Also, I was recently reading up on my ATPL notes and JAR-OPS states that two independent altimeters are required for IFR flight, and if navigating out of sight of the ground, two independent VHF radios.

Based on that information, I assume a C172 with one servicable radio and only one altimeter isn't good for IFR/IMC flight...?

[Brooklands]

I think that the requirements for dual altimetes and radios only apply in controlled airspace (eg the airways). The requirements outside of CAS are less onerous, but I can't remember what they are. I'm not quite sure how two radios would help you navigate out of sight of the surface - are you sure that the requreiment is for two radio nav-aids?

As always the answer will be in the ANO or the AIP

Brooklands

[bookworm]

I don't believe IFR needs to be explicitly stated on the C of A, but the C of A incorporates any limitations in the AFM.

In the UK:

Dual altimeters (according to Schedule 4) required for:

* All IFR in A/B/C airspace
* Public transport under IFR except if outside controlled airspace and MTWA less than 1150 kg
* Public transport at night except if MTWA less than 1150 kg

Dual VOR (aaccording to Schedule 5) required for:

* Public transport under IFR
* Public transport under VFR if multi-engine

[mm_flynn]

If your 172 has the words Not Certified for IFR flight, Certified for VFR flight Only, IFR flight not authorised, or VFR Only (in the operating limitations) or other similar language then it is not certified for IFR. If there is no restriction in the POH/AFM then there is no restriction.

To expand on Bookworm's post, the equipment requirements for IFR (Class G) are minimal (altimeter, gyros, a time piece, thermometer, and rate of climb indicator) beyond those required for day VFR. For Class D a radio, transponder, dme, vor are required as well),

[Contacttower]

I assume that instruments need to be inspected to make sure they are suitable for IFR flight in order for a plane to remain unrestricted? If a plane has non-FM immune radios does that mean that it can't fly IFR in controlled airspace?

[George T]

Hi Finals
I don’t mean to be rude but if you have flown in any IMC then you would always want to know your altitude and have a back up to check it and generally speaking the more kit the better.
If your C172 has minimal equipment and you are just starting IMC work then I would think long and hard before going out there. It’s very lonely in the clouds.

George T

[Dan Dare]

Of course, you wouldn't need to be in IMC to be flying under IFR

[High Wing Drifter]

If a plane has non-FM immune radios does that mean that it can't fly IFR in controlled airspace?

For Comms and less than 5700kg (I think), no. For VOR, as flight in CAS mandates those for carriage, then they must be FM Immune. immune ILS is reqiured for ILS approaches.

Best check for your self: Airworthiness Notice 84 on the CAA site.

[A and C]

If you fly an ILS approach the aircraft must be fitted with an FM immune ILS reciver, if you use the VOR for IFR navigation it must be FM immune, quire simple No FM immunity No IFR navigation with that bit of kit.

[IO540]

if you use the VOR for IFR navigation it must be FM immune, quire simple No FM immunity No IFR navigation with that bit of kit.

Reference?

FM immunity is for IFR in CAS and this refers to equipment carriage; there is no legal prescription on equipment usage.

In Class G you can navigate with a rubber duck in a bucket of water

[bookworm]

In Class G you can navigate with a rubber duck in a bucket of water

A "rubber duck"? How can you navigate with a "rubber duck"? Everyone knows that the Usenet navigational standard has been a tuna sandwich for many many years.

[Contacttower]

I think I've found the answer; obviously in class G you can do what you want (including electing to fly IFR without FM immune radios/nav) except if you want to do an ILS approach inside or outside controlled airspace it must be FM immune. Inside controlled airspace VOR reciever must be FM immune for IFR flight as well.

[A and C]

Let's hit a mountain!

The reason for the FM immunity regulations was that the aviation authoritys in europe had let commercial radio transmitters to broadcast right up to the bottom end of the aviation band.

This may effect the performance of aircraft navigation kit in the VHF range.

It would seem to me that all this talk of the leagality of using non FM immune kit in IFR is just stupid, after all the mountain or tall building that you hit is unlikely to know if it is in class A or G airspace.

[IO540]

The FM Immunity requirement is a theoretical thing; I don't believe there has been a single demonstrated instance of interference.

Anyway, it's not easy to fly OCAS in the UK, at the required low levels, while navigating by VORs alone. There are significant gaps in the coverage. If somebody is flying in IMC today they are much more likely to use a GPS, with VOR/DME backup.

[A and C]

I agree with you but the real problem is that the ILS LOC is also subject to the immunity problem, 200ft above the ground is not the place to discover that this problem is not "theoretical"

[mm_flynn]

Originally Posted by A and C

The reason for the FM immunity regulations was that the aviation authoritys in europe had let commercial radio transmitters to broadcast right up to the bottom end of the aviation band.

While, I believe the statement is true (i.e. stations up to 107.9 are used in the UK), it still doesn't quite answer the question of why Europe with an FM allocation of 87.5-108 has a real risk of 'airplanes crashing' while the US using 87.9-108 (107.9 FM is commonly used) doesn't seem to feel there is a risk.

Is it US transmitters are better, N-Reg planes are better wired, American pilots are better at identifying interference, the US just accepts a level of IFR 'debris' falling around the country? or is it European Gold Plating?