FM Immunity - costs

[Diplomate]

Help please - we have a very well equipped group aircraft that doesn't comply with the FM immunity rules. Has anyone any ideas about what costs are likely to be involved in acheiving compliance? Are we talking about entirely new kit or are there filters available?

Many thanks

[BEagle]

I've just had 3 of 4 aircraft modified to comply (the 4th goes in at the end of October) - the cheapest involved just changing a KX155 for an outwardly identical FM-immune KX155 and that cost about £2500. That gives us FM-immunity compliance on VHF navigation (VOR and ILS localiser) and also FM-immunity on VHF communications - although that isn't essential on light ac just yet.

But that assumes that it's just a 'fit form function' swap over. The most expensive modification to my ac will involve removing 2 KX170s, replacing 2 nav displays, replacing 1 KX170 with an FM-immune KX155 and replacing the other with a non-FMI KX155 from another of my ac. That will cost about £7300.....

I am happy to have a single FMI NavCom as primary radio and VHF nav system and non-FMI systems as day VFR backups for the sort of flying we do (up to IMC Rating level plus flying in Class D airspace under IFR) plus a panel mounted Garmin GPS. If you are really keen, you could always go the 'double Garmin' route if you have the funds!

I wouldn't bother with filters - they aren't compatible with every system and the installation cost isn't that much less than a 'proper' NavCom exchange fit.

If you want a really good radio shop, I can't recommend RGV Aviation at Staverton too highly! An absolutely brilliant set up!

[Wee Weasley Welshman]

BEagle - that seems a cheapish good solution. BAE systems went down the route of filters and it turned into a nightmare and more expensive than the path you outlined.

WWW

[BEagle]

WWW - yes, the filters route might seem outwadly attractive, but I was advised that it wasn't going to be as simple as people thought. Hence the avionic upgrade programme I initiated.

These were the actual figures:

COST ESTIMATE FOR AVIONICS FM IMMUNITY COMPLIANCE

1. G-****:

New FMI-compliant KX155 (with install kit): £ 2350
VOR/ILS indicator (OHC): £ 875
Labour: £ 1050
Sundries: £ 250
CAA Minor modification fee: £ 64
Compass check: £ 60
Sub-total: £ 4649
VAT: £ 814
TOTAL: £ 5463

2. G-****:

Exchange non-FMI for FMI-compliant KX155 (without install kit): £ 2250
Rebate $700 @ £1=$1.40 if ordered before 31 Mar 01: -£ 500
Labour: £ 30
Compass check: £ 60
Sub-total: £ 1840
VAT: £ 322
TOTAL: £ 2162

3. G-****:

New FMI-compliant KX155 (with install kit): £ 2350
Labour: £ 30
Compass check: £ 60
Sub-total: £ 2440
VAT: £ 427
TOTAL: £ 2867

4. G-****:

New FMI-compliant KX155 (with install kit): £ 2350
2 x VOR/ILS indicators (OHC): £ 1750
Labour £ 1650
Sundries: £ 325
CAA Minor modification fee: £ 64
Compass check: £ 60
Sub-total: £ 6199
VAT: £ 1085
TOTAL: £ 7284

FLEET GRAND TOTAL: £ 17776

[ 23 September 2001: Message edited by: BEagle ]

[Awful Charlie]

Went through the same woe last year. Having just one FM immune COM, and a lack of panel space, and trying to improve the thing as well, the figure for me were:
GNS430: 5492
KR87: 2964
CAA Minor Mod: 64
14-28V converter: 160
New blind encoder: 150
2nd Used NSD360 HSI: 200
With the installation& VAT, this came out at about 13K - gulp!, but give me
FM Immune COM1/2 & NAV1, IFR GPS, HSI (non-slaved), and ADF that works (the old Bendix T12 had pretty much all but given up the ghost), and 2 ILS's (one of which isn't FM immune, but not required for a Private CofA)

Next to do is change the Nav112 for a later one to make it FM immune, but I'm letting the rush die down for them, as well as getting over the financial hit of the last lot

[ 23 September 2001: Message edited by: Awful Charlie ]

[A and C]

A lot of people are replacing the king KX155 with a KX155 post mod 16 this is the cheaper option but not far over the horizon is the 8.33 com channel spacing ,i know its only for flight above FL245 at the moment but you can bet that its heading this way.

At the moment only the GNS 430/530 and the king KX165A offer 8.33 and both require 28VDC so most aircraft will need a transformer , i would recomend that the 8.33 option is taken if you intend to keep the aircraft as it will save you money in the long run.

Some will doubt my policy but its looking like a repeat of the 360-720-760 channel upgrade of 20 years back !.

[ 24 September 2001: Message edited by: A and C ]