## Monday, July 25, 2011

### Duty Time Math

I've questioned before the exact meaning of the rule restricting flight time when single pilot IFR is conducted. Amongst a long list of how many hours a pilot can fly in a year, 18 days, 90 days, month, week and day, there is this:

720.15(1)(a) where the flight crew member conducts single-pilot IFR operations, 8 hours in any 24 consecutive hours

Does that mean that if I ever fly IFR I may never log more than eight in twenty-four? No. Now I have an official interpretation. It only matters what you have done in the last 24 hours, so you can log twelve hours on Monday, have Tuesday off, and then fly eight hours of SPIFR on Wednesday. But you can't depart IFR on Monday, cancel fifteen seconds after departure, and then fly eight hours and one minute VFR. This could be a legitimate problem, considering all the times that the controllers get confused and give us IFR departures in VFR flight.

GUIDANCE: Where the flight crew member conducts single-pilot IFR flights, the flight crew member's total flight time, in all flights conducted by the flight crew member, will not exceed 8 hours in any 24 consecutive hours. In determining if this limitation applies to a given situation, this question must be asked - did the flight crew member conduct single-pilot IFR flights? Yes or no. If the answer is yes, the flight crewmember is limited to 8 hours of flight time in any 24 consecutive hours. The length of time spent conducting single-pilot IFR flights is irrelevant. If the pilot flew a departure under IFR and then cancelled IFR and flew the rest of the day under VFR - the answer is still yes and the 8-hour flight time limit applies.

The limitation is intended to prevent cockpit fatigue and applies to flight time not duty time. Interestingly, if you departed VFR and got an IFR clearance prior to entering Class A airspace the limitation would start then.

So imagine I flew a five hour IFR mission on Monday, cancelled IFR through 12,500' at 00Z, and landed. If I departed at 1430Z the next morning on an IFR clearance, I'd be illegal after three hours. So imagine I flew a five hour IFR mission on Monday, cancelled IFR through 12,500' at 00Z, and landed. If I departed at 1430Z the next morning, even on a VFR clearance, I'd be illegal after three hours: the regulation says any 24-hour period and during the period 1731Z-1731Z I would have flown eight hours and one minute, including some IFR flying.

But if on Monday the mission was all VFR, from 19-00Z, I could start flying VFR on Tuesday at 1430Z, no problem. Then if I were offered an IFR clearance, as I have been because the controllers like it better, I'd have to decline it at 1730Z, because that would put me IFR with more than eight hours logged in the last 24. If that Tuesday morning flight were only three hours long, I could accept an IFR clearance again at the time I took off on Monday, because then the previous five hour flight would start expiring at the same rate I was logging new time, so I'd be legal until about 00Z, when Tuesday's logged time reached eight hours.

Fortunately, we have an op spec (exception) to this rule for our operation.

I got a hold of the camera place, and they say they can fix the camera for \$95. It's a bit of cash, but I really, really like that camera (a Canon PowerShot SD10) and I haven't seen anything that measures down (it's tiny), so I gave them the go ahead. They couldn't tell me when it would be ready, though.

david said...

As a weekend warrior, I don't have your experience or stamina, but I've done a couple of SPIFR days longer than 8 hours as a private pilot, and they are exhausting (especially if it's all in bumpy actual and there's no autopilot).

Anonymous said...

I know what you mean about the camera. I had (have) a Canon Ixus 850i that was great for one handed intuitive shots.

I lost it, and as it was now obsolete, got one on Ebay for \$75. The day the new one arrived I was looking in the hall hanging space for something, noticed a bulge in a rain coat pocket, and there was my original camera :o( It's good to have a spare I guess.

Cedarglen said...

Those rules, as strange and possibly incomplete as they are, exist to protect you and others. The real rule is to be smart and safe in all flying choices, eh! Nice post. -Craig