Help

[teekaycee]

Have an exam. Can anyone help with answers to the following?

1. What is ISDU?
2. Who derives MOCA and MORA?
3. What is the significance and difference between ILS X, ILS Y, ILS Z?
4. What are mountainous areas?

[captainsuperstorm]

first shot answer.not looking anywhere else like wikipedia, so i could be wrong...did ATPL thousand years ago.

1.internal system drive unit, thats the unit which keep the system at 400hz to run the generator.it s the whole unit, constant speed drive + generator= ISDU, this unit is connected by gears to the engine.

2.clearance altitude, restricted altitude. (clearance is for obstacle, restriction could be for sound by example , ...


3. ILS are separated by 0.5 herz, and can offer only 12 different ILS in the VHF band allowed from .111.9 to 117.9mhz. you want several ILS in case of multiple runways. Each runway can have its own frequency for making parrallel approaches. remember 112,118,124,132 ILS/VOR and VHF range


4. moutain when top is higher than 2000ft. (600meters).
below this it s called hills.

[Milton1995]

A MORA is a JEPPESEN derived (non-official) altitude. "Route MORA values clear all reference points by 1000' in areas where the highest reference points are 5000' MSL or lower. Route MORA values clear all reference points by 2000' in areas where the highest referene points are 5001' feet MSL or higher." (Jepp Intro page 10)
I dont know about MOCA, but assume this is by JEPPESEN too, :)

1720. OBSTACLE CLEARANCE, PRIMARY AREA.
b. Mountainous Areas. Except as set forth in (1) and (2) below, the minimum
obstacle clearance over terrain and manmade obstacles, within areas designated in
FAR 95 as "mountainous" will be 2000 feet. ; An area of high concentraion of mountains, there is no definite definition.

From another question on PPruNe, 'The "Y" and "Z" are just identifiers for multiple approaches based on the same navigation equipment to the same runway with diffrent procedures.' the difference seems to be in the missed approach gradients.

This is all from some research, so please correct me if im wrong,

M1995.

[teekaycee]

Thank you friend. Will let you know if I find different answers anywhere else.