AboutNed Dolan Expertise 38 years as a professional pilot. Worked as an instructor for a major airline, as a tow pilot towing gliders and flew international routes until 1998. Do not know much about the maintenance end of the business.
Experience Teaching new Captains the skills and knowledge needed to
occupy the position.
Helping develop procedures for use in a new airplane
type. (B757)
Question Hi there, I am a third year student studying Aviation Technology at the University of Leeds, England.
I am currently writing my dissertation which is mainly focused on Instrument Landing Systems.
At the moment I am researching Range Information. I have allready covered Marker Beacons, DME and GPS methods in quite some detail but I am aware that pilots may use RADAR to determine distance whilst making an instrument landing.
In what way do they go about this? Is it as simple as receiving RADAR ranges over the radio from ATC or can they do it without the help of an ATSU?
Any information on Cross-radial ranging would be also be greatly appreciated.
Thanks a lot.
P.S. May I use you as a reference in my dissertation?
Answer Hi Chris:
In regards to range information during an ILS approach:
The outer marker is the primary range indicator during an ILS to identify the final descent point. It is extremely important to identify a known range and corelate it with an altitude to ensure that a "false" glideslope inidication is not present.
This known altitude/range postion can also be indicated by a VOR radial, DME fix, or a GPS fix. I have never heard of using a radar fix this purpose, but I suppose if other methods were unavailable due to outages that a controller could give a pilot the fix using the ATC radar.
Using on board weather radar could not be approved as it is not able to clearly identify ground positions.
Cross radial ranging is often used to identify initial descent fixes and also intermediate fixes on the approach, in many cases to control noise as much as to separate traffic. It also can be used to identify a final descent point, but the OM usually is used.
