ICAO ATC Procedures

[MTBrulz]

quick question regarding ATC Approach Procedures...

here's the background:

we're flying in the carribean, no radar control, 30 NM form the airport expecting an approach via a dme arc. already cleared direct to a fix (which is an IAF) but we're flying off any published routes.

levelled at 8000' ATC says "cross fix at or above 3000', you're cleared for the approach".

here's my confusion:

can I descend to cross that fix as soon as ATC gives the clearance eventhough I'm not on a published route? or should I wait untill established on the published procedure to descend?

in other words, will ATC guarantee terrain clearance when you're off an airway, SID, STAR, Approach segment, etc?

Thanks in advance

[Gooneyone]

I would remain above the grid MORA until within 25NM then descend to the MSA. If the MSA is higher than 3000ft, I would maintain the MSA until joining the DME arc - remember you were cleared to join the arc at or above 3000ft.
Off route, non-radar, I will ensure my own terrain clearance.

[aterpster]

MTBrulz:

in other words, will ATC guarantee terrain clearance when you're off an airway, SID, STAR, Approach segment, etc?

I sure wouldn't bet my life on it, especially anywhere other than the U.S., Canada, or Western Europe.

Can you provide us the name of the IAP and your approximate location when you received that approach clearance?

[Spitoon]

Under ICAO rules in a non-radar environment the pilot is entirely responsible for terrain clearance. In essence, the level that you are cleared to at a fix will be safe but in the absence of any other instructions, how you get there is down to you. Obviously I can't speak for the airport you are thinking of but when I did procedural approach I issued terrain safe clearances but there wasn't a lot of challenging terrain nearby so it wasn't difficult.

[9.G]

ICAO rule is clear on this subject NO descent below MSA unless established on published procedure or visual. If not visual I'd descent over the IAF to MSA and then execute the procedure including the holding down to 3000 ft if necessary.