Issue on Non Calibrated Instrument Approach

[Encourager]

Hello Everyone,

A question on the above. NOTAM says ILS is serviceable but not calibrated and use with caution. Does it mean that it can be used only during VMC and with caution. I suppose legally it is not the instrument approach to opt for in IMC. Many aviators may be flying the ILS but if any incident were to happen, I tend to understand that company may not even support it. Any pointers?

[OzExpat]

Certainly a very strange Notam, if that's all it says. I'd expect that, as the ILS is radiating, there'd be additional information about it being on test and, perhaps, the ident might be transmitted as something like "XP", "TST" or similar. In any event, as the Notam states "not calibrated", it could be a significant risk in using it in IMC.

[Encourager]

I supposed what the NOTAM meant was that the equipment might have been declared serviceable on the ground but yet to be properly calibrated with a flight test. Or perhaps it was flight tested before but needed to conduct another flight test possibly due to some complaiits of its unreliability from other flight aviators.

[Check Airman]

I'd tune it, but disregard any GS deviation alerts. Obviously I'd only "use" this thing after I have the field in sight. Strange NOTAM indeed. To my mind, it's either working or it isn't.

[411A]

These types of notams appear from time to time (although worded slightly differently) and usually refer to the specific navaid needing a flight test, as the old one had expired.

I recall years ago when working for SQ my First Officer wanting to know just why an FAA registered NA265 (Sabreliner) was parked on the Paya Lebar ramp.
I explained that in many cases the FAA sends their navaid calibration aircraft worldwide to access the suitability of navaids for US aircarriers operating there or under contract to respective countries, when they do not have that capability.
The contracting country pays for the fuel and HOTAC for crew, the rest is paid for by the FAA, at least at that time.
He was quite surprised that the FAA would provide this service, especially when I introduced him to the crew of the FAA aircraft which oddly enough I had met in Dubai a few months previously.

[ComJam]

That is a very odd NOTAM. From my point of view, as a calibrator, i wouldn't use any ILS that hasn't been Flight Checked. There are only a certain number of checks that the ground radio (Tels) engineers can perform, the only way to accurately check the angle of the GS and the alignment of the LOC is to Flightcheck it.

In the past, on Flight Checking a new ILS installation we found the GS to be radiating "upside down" despite the engineers stating that it would "all be good"! Full "fly-down" at 12nm to full "fly-up" at the threshold....