Hi Bob & forum,

My query relates to Appendix 4 Research Questions (page 123), Question 4.

You are assigned to commence a FDP at 0530 LMT and a 6 hour rest period with sleeping accommodation has been provided after the first 3 hours of the FDP. The latest time at which you must be relieved of duty is -

The answer in the book states:

The maximum FDP for a 0530 LMT start is 9 hours. Even though you have been given a 6 hour split duty rest period, the maximum extension permitted is 4 hours. 0530 + 9 + 4 so that's an 1830 LMT finish time.

This answer refers to Appendix 4 para 3.1, but I assumed that 3.5 would also apply: Any remaining portion of an FDP following a split-duty rest period must be no longer than 5 hours.

Given that the rest period starts "after the first 3 hours of the FDP" the second portion of the FDP would have to be 6 hours to make this answer correct. Shouldn't the second portion be reduced to the maximum of 5 hours [as per 3.5] and the finish time actually be 1730..? This is not one of the answer options but I'm struggling to see why 3.5 doesn't apply here but 3.1 does.

Appreciate any insight.

--Nick

(I struggled with this myself. I’ll try to explain how I see it now.)

Bob’s answer: 0530 + 9 + 4 so that's an 1830 LMT finish time.

“9” in the equation refers to a) the first 3 hours of the FDP plus b) the 6 hour rest period.
“4” is the maximum allowed increase to the FDP according to clause 3.1.

The ‘remaining portion of an FDP’ in this case is only 4, so clause 3.5 need not apply.

On closer inspection, I can't explain why Bob's answer to this question DOESN'T include a reference to clause 5.3 which states,

"...in unforeseen operational circumstances at the discretion of the pilot in command, the FDP limits in the operations manual may be extended by up to 1 hour."

Since the question asks when you must be "relieved of duty" (and not, how much FDP you "may be assigned"), might the answer be,

0530 + 9 + 4 + 1 so that's an 1930 LMT finish time.