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downwindabeam
1st Jun 2009, 19:51
Hello ,

Was wondering how do you guys who regularly fly over either the atlantic or pacific deviate when you have to around WX cells while NOT in positive radar control?

Is it all about TCAS at that point?

How is all this orchestrated...?

Thanks!

-downwindabeam

galaxy flyer
1st Jun 2009, 20:20
Make a request "Weather Deviation Required" and specify a distance off track to clear the weather and you will usually get approved. Jepp has a the whole drill including in the case ATC cannot approve the deviation, in which case, you deviate with a maneuver in altitude to provide the best clearance, using TCAS.

Suggest reading the whole Jepp version. The weather in the NAT region rarely requires deviations, but the Mid-Atlantic and Pacific are another story.

GF

Henry VIII
1st Jun 2009, 20:24
A lot of differences according your situation. HF only or CPDLC ?
In NAT you can refer to this doc (http://www.nat-pco.org/nat/MNPSA/MNPSA_2008.pdf), where specific procedures are described.
Bigger problem when HF only... no way to talk with them and... huge CB closer and closer :} Some times you may need to deviate and/or climb ralating on TCAS only and... all lights on ! Of course communicating via 121.500 and dedicated air/air frequencies to all other listening traffic(s).

Beires
1st Jun 2009, 20:29
11.4 DEVIATIONS AROUND SEVERE WEATHER

11.4.1 If the aircraft is required to deviate from track to avoid weather (e.g. thunderstorms), the pilot should request a revised clearance from ATC and obtain essential traffic information, if possible prior to deviating. However, if such prior ATC clearance cannot be obtained, the procedures described below should be adopted and in the meantime efforts should be continued to obtain an appropriate ATC clearance.

a) If possible, deviate away from the organised track or route system;
b) Establish communications with and alert nearby aircraft broadcasting, at suitable intervals: aircraft identification, flight level, aircraft position (including ATS route designator or the track code) and intentions, on the frequency in use and on frequency 121.5 MHz (or, as a back-up, on the VHF inter-pilot air-to-air frequency 123.45 MHz);
c) Watch for conflicting traffic both visually and by reference to ACAS/TCAS (if equipped);
d) Turn on all aircraft exterior lights.
e) For deviations of less than 10 NM, aircraft should remain at the level assigned by ATC;
f) For deviations of greater than 10 NM, when the aircraft is approximately 10 NM from track, initiate a level change of 300 ft.
- If flying generally Eastbound (i.e. a magnetic track of 000° to 179°) and deviating left (ie north) of track then descend 300 ft; if, however, deviating right (i.e. south) of track then climb 300 ft.
- If flying generally Westbound (i.e. a magnetic track of 180° to 359°) and deviating left (i.e. south) of track then climb 300 ft; if, however, deviating right (i.e. north) of track then descend 300 ft.
g) When returning to track, regain the last assigned flight level, when the aircraft is within approximately 10 NM of centre line.
11.4.2 The pilot should inform ATC when weather deviation is no longer required, or when a weather deviation has been completed and the aircraft has returned to the centre line (or previously adopted SLOP Offset) of its cleared route.