Tired or fatigued?
There are many definitions of being "tired/fatigued", however, the non-aircrew public might not appreciate the subtle differences.
Some years ago I used to fly regular UK-LXR-UK charter operations; also, MAN-DLM-MAN and, MAN-TFS-MAN; all of which were pretty gruelling experiences and not well-liked by both CC and FD crew. They were quite tiring nights out of bed but that I'd never say that I was "fatigued" by the experience.
Some years later when I was flying cargo for airline XYZ I did experience the "fatigue" factor. Crew Scheduling thought that they were being kind in providing 24-hours rest between work patterns; hence, it became a mix of both night and day sectors with 24-hours-off in-between. I went beyond the stage of being tired and irritable... I was falling asleep during the final approach path back into base!
Picture this if you will... make an early start (0400L) and fly a fouteen-hour duty (two-sectors); back home by 1830L; have a couple of beers with friends and then go to bed at 2200L (tired); take ten-hours sleep (awake at 0800L); report for duty at 1800L. I then fly a twelve-hour out and return duty (two-sectors); back into base at 0600L; home by 0630L (very tired); sleep for ten-hours (awake at 1630L). My next report time is at 0600L; however, having awoken from sleep at 1630L I'm now not really tired until very late that same night; hence, you try and sleep; except that it doesn't come easy... the process continues. It's now when "fatigue" sets-in; the process is cumulative.
Given that friends and colleagues were commenting upon how irritable I was becoming, and, couple that with the falling asleep syndrome on final approach, I made the decision to go sick and see my doctor. He diagnosed that I was fatigued and that he was concerned that I was becoming clinicly depressed; he signed-me-off for two-weeks sick leave. My Company wasn't impressed and asked for a second-oppinion... provided by a Senior CAA Medical Officer (it was, in fact, the head of that particular country's CAA Medical Organisation). He interviewed me for thirty-minutes and said, "Mr TheChitterneFlyer, I cannot reccommend two-weeks sick leave; I'm signing you off for six months"!
The "Corporate machine" went into full swing and stated that I couldn't leave the country whilst on sick-leave (which was reccommended by my AME). The said CAA man tidy'd the loose ends and I ended-up on the next schduled flight to the UK... twelve hours later; home and dry, but knackered!
Three months later I considdered myself fit for duty (and medically assessed as being fit) and eventually returned to country XYZ. I was now tainted as being a trouble maker; six months later, I resigned... it was starting to happen all over again!
"Fatigue" creeps up on you when you least expect it to; remember, it's a cummulative process; that's the difference to being "very tired"!
Despite all of the corporate paperwork that's required of you to "fill-in" when you're feeling "fatigued"... make sure that you have accurately documented all of your previous duties; you'll otherwise get "screwed" if you haven't exceeded your "agreed" flight time limitations schedule. The "wording" of those FTL documents are extremely vague; including such words as "should"! Airline XYZ "should" not schedule rest periods between 18 and 30 hours rest... your corporate machine will play on those words "should not"... they'll say, on this occasion, it wasn't avoidable!
Be carefull out there; particularly in foreign parts!
TCF