FAQ n.47576

Acclimatisation ORO.FTL.105(1): How should we determine the state of crew member acclimatisation in complex rotations?


Acclimatised crew members

A crew member is considered to be acclimatised to the time zone of the reference time for the first 48 hours.

In the following example there are 4 departure places: A, B, C and D and the crew member is in a known state of acclimatisation all the time. 

  • between A and B there is a 2-hour time difference 
  • between A and C – a  4 hour-time difference
  • between A and D – a  6-hour time difference

Day 1:  The crew member starts acclimatised at A and finishes at B. The reference time is the local time at A, because the crew member is acclimatised at A and reports at A. The time difference between A and B is 2 hours. That means that after resting at B, the crew will be considered acclimatised at B.

Day 2:  The crew member reports at B acclimatised to the local time at B for an FDP to C. At C the crew member has a rest period and becomes acclimatised to C. He/she has now covered 4-hour time difference, but in 2 days. 

Day 3: The crew member reports at C acclimatised to the local time at C for an FDP to D. At D the crew member has a rest period and becomes acclimatised to D. He/she has now covered 6-hour time difference.

Day 4:  The crew member reports again considered to be acclimatised at D. The local time at D is the reference time. The FDP between D and A covers 6-hour time difference. Crossing 6-hour time difference in one day (one FDP) induces time zone de-synchronisation. If the rotation finishes at A, the rest requirements in CS FTL.1.235 (b)(3)(i) are applicable.

Unknown state of acclimatisation 

After the first 48 hours of the rotation have elapsed, the crew member is considered to be in an unknown state of acclimatisation. 

The crew member only becomes acclimatised to the destination time zone, if he/she remains in that destination time zone for the time established in the table in ORO.FTL.105 (1). 

During that time the crew member may have the rest in accordance with CS FTL.1.235(b)(3) and/or take other duties that end in different time zones than the first arrival destination, until he/she becomes acclimatised in accordance with the values in the table in ORO.FTL.105(1). In the case of duties to different time zones, the state of acclimatisation should be determined in accordance with GM1 ORO.FTL.105(1) (d)(3).

Where the rotation  continues with duties to/from subsequent destinations, the greatest time difference from the reference time should be used for the purpose of rest in accordance with CS FTL.1.235(b)(3)(i). 

Time elapsed since reporting (h) in the tables ORO.FTL.105 (1) and CS FTL.1.235 (b)(3)(i) is the time that runs from first reporting at home base to the reporting at destination and includes the FDP from home base to destination plus layover time.   

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