FM immunity - thoroughly confused by Pilot magazine
Sorry, but that is not correct. Look at schedule 5 to the ANO and at the table under paragraph 2 of the Schedule. An aircraft requires "Radia navigation equipment capable of enabling the aircraft to make an approach to landing using the Instrument Landing System". This applies to making an approach to an aerodrome "... notified for the purpose of this sub-paragraph".
AN84 specifies non FM Immune instruments be limited to VFR only.
"NOTE: For aircraft of 5700 kg MTWA or less, an acceptable means of compliance is to placard and restrict non-immune receivers to operations permitted under the Restricted Approval Category LA Class 3 (see paragraph 5.4), irrespective of the approval category for that equipment."
LA Class 3 receivers may be used for the facilitation of any flight (VFR or IFR) outside controlled airspace.
Airworthiness Notice 84 states:
"5.2 Requirements for ILS localiser and VOR receivers effective from 1 January 2001:
(a) ILS localiser and VOR receivers, required to be carried.by UK registered aircraft for the purposes of operations under Instrument Flight Rules (IFR) in accordance with applicable airworthiness and operational regulations, must be of a type approved as complying with the improved FM broadcast immunity standard.
(b) Where non-immune ILS localiser and VOR receivers remain installed, (i.e. those carried in addition to the minimum number required by applicable airworthiness and operational regulations to meet IFR), they must be identified to the flight crew and their use restricted to Visual Flight Rule (VFR) operations.
NOTE: For aircraft of 5700 kg MTWA or less, an acceptable means of compliance is to placard and restrict non-immune receivers to operations permitted under the Restricted Approval Category LA Class 3 (see paragraph 5.4), irrespective of the approval category for that equipment.
5.3 Requirements for VHF communications receivers effective from 1 January 2001:
(a) VHF communications receivers, required to be carried by UK registered aircraft over 5700 kg MTWA for the purposes of operations under IFR in accordance with applicable airworthiness and operational regulations, must be of a type approved as complying with the improved FM broadcast immunity standard.
(b) Where non-immune VHF communications receivers remain installed in UK registered aircraft over 5700 kg MTWA, (i.e. those carried in addition to the minimum number required by applicable airworthiness and operational regulations to meet IFR), they must be identified so as to alert flight crews to the potential risk of interference.
(c) UK registered aircraft of 5700 kg MTWA or less may continue to be operated under IFR with non-immune VHF communications receivers provided that the receivers are identified so as to alert flight crews to the potential risk of interference.
NOTE: CAA will continue to monitor reports of interference and, if necessary in the light of experience, reconsider this relaxation from the ICAO standard for VHF communication receivers carried by aircraft of 5700kg MTWA or less."
Basically this means that if you're using a VOR or ILS
anywhere in the UK in a light ac, unless you're under VFR, you MUST have a FM-immune Nav receiver. However, your light aircraft Com transceiver doesn't need to be FM immune.
I went through this whole absurd nonsense a couple of years ago and it cost £17k to upgrade all my 4 ac to FM-immunity compliance requirements.....believe me, if it hadn't been essential I wouldn't have spent that amount of money unnecessarily!
"5.2 Requirements for ILS localiser and VOR receivers effective from 1 January 2001:
(a) ILS localiser and VOR receivers, required to be carried.by UK registered aircraft for the purposes of operations under Instrument Flight Rules (IFR) in accordance with applicable airworthiness and operational regulations, must be of a type approved as complying with the improved FM broadcast immunity standard.
(b) Where non-immune ILS localiser and VOR receivers remain installed, (i.e. those carried in addition to the minimum number required by applicable airworthiness and operational regulations to meet IFR), they must be identified to the flight crew and their use restricted to Visual Flight Rule (VFR) operations.
NOTE: For aircraft of 5700 kg MTWA or less, an acceptable means of compliance is to placard and restrict non-immune receivers to operations permitted under the Restricted Approval Category LA Class 3 (see paragraph 5.4), irrespective of the approval category for that equipment.
5.3 Requirements for VHF communications receivers effective from 1 January 2001:
(a) VHF communications receivers, required to be carried by UK registered aircraft over 5700 kg MTWA for the purposes of operations under IFR in accordance with applicable airworthiness and operational regulations, must be of a type approved as complying with the improved FM broadcast immunity standard.
(b) Where non-immune VHF communications receivers remain installed in UK registered aircraft over 5700 kg MTWA, (i.e. those carried in addition to the minimum number required by applicable airworthiness and operational regulations to meet IFR), they must be identified so as to alert flight crews to the potential risk of interference.
(c) UK registered aircraft of 5700 kg MTWA or less may continue to be operated under IFR with non-immune VHF communications receivers provided that the receivers are identified so as to alert flight crews to the potential risk of interference.
NOTE: CAA will continue to monitor reports of interference and, if necessary in the light of experience, reconsider this relaxation from the ICAO standard for VHF communication receivers carried by aircraft of 5700kg MTWA or less."
Basically this means that if you're using a VOR or ILS
anywhere in the UK in a light ac, unless you're under VFR, you MUST have a FM-immune Nav receiver. However, your light aircraft Com transceiver doesn't need to be FM immune.
I went through this whole absurd nonsense a couple of years ago and it cost £17k to upgrade all my 4 ac to FM-immunity compliance requirements.....believe me, if it hadn't been essential I wouldn't have spent that amount of money unnecessarily!
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BEagle-
There's a similar discussion going on in the Flyer forum at the moment. Someone referred to CAP472* as giving reassurance that for IFR outside CAS in aircraft under 5700kg MTWA, FM immune equipment is not required. There is some debate though over what Restricted LA Class 3 allows - the key word seems to be that Class 3 equipment can be used to 'facilitate' a flight, so I guess you could claim to be flying on dead reckoning in IMC with the 'help' of a VOR, there being no stated minimum equipment for IFR outside CAS.
*not available online, so I haven't been able to consult it!
If you look at the next paragraph on from your quote (referred to in the quote) it merely states that 'such equipment may not be used to comply with the requirement for the mandatory carriage of radio equipment' - i.e. outside CAS you don't <I>need</I> VOR/ILS (you could e.g. track NDB's) so don't need FM immune equipment.
Tim
There's a similar discussion going on in the Flyer forum at the moment. Someone referred to CAP472* as giving reassurance that for IFR outside CAS in aircraft under 5700kg MTWA, FM immune equipment is not required. There is some debate though over what Restricted LA Class 3 allows - the key word seems to be that Class 3 equipment can be used to 'facilitate' a flight, so I guess you could claim to be flying on dead reckoning in IMC with the 'help' of a VOR, there being no stated minimum equipment for IFR outside CAS.
*not available online, so I haven't been able to consult it!
If you look at the next paragraph on from your quote (referred to in the quote) it merely states that 'such equipment may not be used to comply with the requirement for the mandatory carriage of radio equipment' - i.e. outside CAS you don't <I>need</I> VOR/ILS (you could e.g. track NDB's) so don't need FM immune equipment.
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So which aerodromes do you think are "notified for the purpose of this sub-paragraph"? I can't find a single such notification in the AIP
I may have confused the situation here. There sems to be a difference between cases where there is a requirement to have a VOR/ILS fitted and the general position where if you use a VOR/ILS it must be FM immune.
Bookworm: I am afraid that "Restricted Approval Category LA Class 3" does not help as it simply clarifies the general requirement for FM immune kit by allowing you to placard non FM immune as "VFR only" rather than replacing it. It does not provide an exemption from the general requirement.
The whole thing is absurd, since you can legally be forced, if you stick to the letter of the law, to do NDB/DME approaches with all the imprecision that involves whilst you have what is in reality a perfectly good VOR/ILS on board. I know which one I'd use
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I would like to resurrect this thread as I am still quite confused as to what the requirement is:
In AN84, the "Note:" under 5.2 says that for A/C < 5.7t plcarded non FM Immune ILS/VOR receivers are permitted under Restricted Approval Category LA Class 3. What is this category and where can I find the correct supporting documentation? CAP208 has been withdrawn.
Help!
HWD.
In AN84, the "Note:" under 5.2 says that for A/C < 5.7t plcarded non FM Immune ILS/VOR receivers are permitted under Restricted Approval Category LA Class 3. What is this category and where can I find the correct supporting documentation? CAP208 has been withdrawn.
Help!
HWD.
The wording in CAP 208 is (was) as I quoted above, HWD. They may be used for the facilitation of any flight, VFR or IFR, outside controlled airspace. Aerocoms have put the relevant section on the WWW.
Note that I do not agree with Aerocom's interpretation of AWN84 on other pages.
Note that I do not agree with Aerocom's interpretation of AWN84 on other pages.
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IO540
I'm not an engineer, but I seem to recall that the issue was created by the desire of government to free up radio frequencies for commercial use.
It thus seems logical to conclude that even if there isn't any interference now, there may be in the future, if there is a take up of the extra capacity.
Unless one views this whole thing as a conspiracy to persuade people that private flying is too expensive to start/continue, then maybe the FM immunity issue is a future problem being dealt with now?
I have asked and asked and have never come across anyone who has ever heard of FM interference having actually happened.
It thus seems logical to conclude that even if there isn't any interference now, there may be in the future, if there is a take up of the extra capacity.
Unless one views this whole thing as a conspiracy to persuade people that private flying is too expensive to start/continue, then maybe the FM immunity issue is a future problem being dealt with now?
