indian ocean ops
 

hello folks

for those of you more familiar with that area flying along the routes from the middle east to southern india, sri-lanka and the maldives, what is the correct procedure for a driftdown from an operational standpoint taking into consideration that:
aviate first - fly the aircraft, apply rudder, mct, identify, verify, checklist
navigate second - to your drftdown altitude at the driftdown speed: i presume you offset your course laterally ( of how much? 15nm left or right?) first and then you descend ( the higher between your driftdown altitude and the altitude applicable to the course to the enroute alternate basd on the EPT) unless you have a rapid decompression, which in that case you start descending as you turn to the offset!
communicate: inform the atc on the active frequency and the surrounding traffic on the 121.5 emergency frequency about your intentions.
is this the right sequence?
how many nm do you offset your altitude?
if, for instance, the driftdown altitude for the current mass is let's say 26350ft, and you are turning towards mumbai, would the correct procedure call for offsetting your track - in which direction - and then only once established on the offset to descend to the correct altitude - FL260 in our case for a westerly track or you level off at the altitude plus, minus 500ft as over the atlantic? is that portion of the indian ocean rvsm?
many thanks and sorry for the silliness of the question.

baobab72

during driftdown, it is not your choice when to descend. acft performance dictates it.

@capt - there are two options during the start of the driftdown. You can start down immediately or choose to maintain altitude, while deaccelerating from cruise speed to E/O speed, while starting your offset.

Slowing to E/O speed allows about 10 n.m. of offset before the actual descent begins.

driftdown
 

dear folks

in the aircraft that i operate the driftdown procedure calls for maintaining the current altitude until the speed decays to the driftdown speed for the aircraft mass, initial FL and ISA - ISA, ISA-10, ISA+10 -, with the other engine set at the MCT. once the speed reaches the driftdown speed press FLC and descent at the bugged airspeed to the level-off altitude.

my initial question was more operational: in the specific area - indian ocean along an airway - while you wait for the airspeed to decay to the driftdown speed, you normally initiate to offset your track - of how much? is there a given value? once you are on the offset track, you descend to a specific altitude - which one? rvsm above 290, track level below, based on magnetic track plus or minus 500ft?
once you are at the proper aaltitude, you turn to the applicable enroute alternate based on the ETP.

tks

baobab72

A few items for consideration:
The Indian Ocean is not NAT mnps airspace.
There are fixed airways,not an organised track structure that you would see in the North Atlantic.
There is significantly less traffic along the airways and they are also bi-directional..

http://trainati.com/PDF/Special_Proc...c_Airspace.pdf

it is rvsm airspace. initiate descent and give a call on mumbai hf frequencies or if unable, mumbai 132.7 if north of p574 and 125.35 p574 and south of it, ask for a relay and you can expect a lower level and direct BBB once clear of conflicting traffic. the same goes for muscat control if heading in that direction.

sureshot hf frequencies are 8879, 10018 during day and 3467, 5658 during night time.