Mutt,
Surprised that you haven't investigated the feasability of APR OFF Takeoffs. For one APR aircraft that I do work for, APR Armed wins the day for obvious reasons when Obstacle Limited, but APR Off wins hands down (by a large margin) when Field Limited, in particular Accelerate-Stop, or on Wet or contaminated runways. Lower Vmcg means lower V1, and less distance travelled at the lesser thrust at Normal (Non-APR) thrust on the remaining engine for the interval between Vef and initiation of reject actions. Definately FAA approved (at least for this type), one Alaskan short-ish airport that I just did work for showed greater weights possible at APR OFF in 85% of cases compared to APR Armed.
John_T,
Your question -"
don't folk these days still both check the performance figures ... ie, typically F/O prepares and captain runs either rule of thumb, familiarity, or even book checks ?"
My answer - It's on my wish list, but it never seems to happen consistantly. Between my last post and this one, on a hot and highish airport near where
mutt lives, the F/O and I independantly prepared the takeoff data. Now comes the cross-check.
F/O - "I figure we can go at TO-1 and Assumed temperature 36 degrees"
Me - "The outside temperature is 42 degrees"
F/O - "Yes, we can go with Assumed Temperature 36"
Me - "No we can't, that's more than available at 42 degrees, but we CAN go at Full TO-1 and the Improved Climb Speeds"
F/O - (Shuffle shuffle, scratch head, look at Airport Analysis from every angle), "Yes, I guess that we can, but I don't see how"
Me - "We'll talk about it in cruise, let's compare your new figures"
(Figures agreed, now comes loading the speeds into the FMC)
F/O - "There's something wrong with the FMC, the Analysis speeds are Waaayyy above FMC speeds"
Me - "They're supposed to be, let's talk about it in cruise"
We did talk about it in cruise, and I spent the remaining 6 hours wondering why I'd bothered to take 6 freaking months writing what I thought was a damned good Performance Training Manual, when I could have been fishing, or screwing, or Ppruning, or.........
Universal understanding is still on my wish list however.
barit1,
As
411A would say, "Yup, Good ole thread!" (Thought of him when I saw one of his babies at said airport, the L1011 is a beauty!)
PS -
Mutt, sorry for delay, documentation mentioned in recent PM being retrieved from the archives.
Rant over.
Regards,
Old Smokey