Runway alignment of ILS approaches
 

Hi,

Could people let me know what requirement if any there is for runway alignment for ILS approaches, what is the alignment requirement for CAT I to CAT III.

Can anyone give men examples of where in the world ILS approches exist (or used to exist) without runway alignment. I think Hong Kong may have had one ....

URLs to approch plates for example airports would be appreciated, or airport idents.

Thanks

DS

Nice has a 2° offset on the ILS 04R.

JFK ils 22R has offset of 9*

seems barmy to me and doesnt half look odd when you break mins.

Pago Pago has ILS offset due to a 500+ foot hill in proximity to threshold. (Special Airport Qualification). :cool:

In Canada an ILS has to be aligned within 3 degrees if not it's called a localizer type approach and would have non-precision approach minimums.

The old Hong Kong ILS was actually called "IGS" (G = Guidance). The general criteria for runway-alignment is found in Pans Ops, for the countries using that criteria, or TERPS for the USA and a few other countries.

If the airport doesn't handle international flights, the regulator can establish any appropriate local criteria in consultation with the companies using that airport. The issue is a bit more complex for airports that handle international air traffic, but you could do worse than reading up on the simple few paragraphs in Pans Ops, that explain what constitutes a runway alignment.

There are cases, for example where the final segment only needs to cross the extended centreline of the runway, to be termed runway-aligned.

Bodø(ENBO) and Bardufoss(ENDU) in northern Norway have offset ILS-approaches. Both due to terrain in the approach area.

For a CatIII approach, the ILS cannot be offset as it gives ground roll guidance. If it was offset the aircraft would follow the signal off the runway.

TickleTackle

The ILS for 22R at JFK is not offset by 9°, but only by 3°, with the final approach course intersecting the extended centre line at 2,512 feet from the runway threshold.

Time for a new set of approach plates. :D

ILS for 08 at the Isle of Man is offset by I think 4 degrees because of terrain. Quite odd when you fly one for the first time.

I recall, and please correct me if I am wrong, the IOM 08 ILs was put in as direct result of a UK CAA report into two (same day)seperate incidents of HS748 aircraft on Vor 08, early morning approaches, in fog.
These Vor approaches were to say the least "creative" as flow by the UK Atpl rated pilots, as to heights flown and at what points of the approach these heights were achieved. They were lucky.
This report makes a chilling read, and a valuable lesson in DME orientation.
The IOM and uk Caa are to be congratulated IMHO for sorting this approach situation out in under 18 months by putting in an ILs.and seeing if their legally fatigued pilots can follow that.