767 flaps 20 takeoff retraction schedule

[reverserunlocked]

Just fiddling around with the 767-300 perf calculator for a hypothetical EGJJ-EGLL leg using tonight's weather and it gives me a flap 20 takeoff. Now, with VREF30 being 135 and the retraction schedule calling for flaps 5 at 155, there doesn't seem to be much time to get from flaps 20 to 15. Do you retract 20 from 155 to get the flaps 15 retraction speed, i.e 135? I imagine that would be a 'busy' departure?

TAKEOFF: EGJJ/JER JERSEY RWY 09 FLAPS 20 ELEV. 277FT ( 84M)
LANDING: EGLL/LHR LONDON HEATHROW RWY 27R FLAPS 30 ELEV. 83FT ( 25M)
ALTN 1: EGKK/LGW LONDON GATWICK ELEV. 203FT ( 62M)
ALTN 2: EGGW/LTN LUTON ELEV. 526FT ( 160M)

//////// TAKE-OFF ////////

APT PRWY POAT PWIND PQNH PMRTW FLP CONF THRUST V1 VR V2 PTOW
EGJJ 09 +0°C 090/15 1005 119895 FLAPS 20 D-TO +64°C 122 122 128 119439

RMKS - CALCULATIONS VALID AT QNH 1000 AND ABOVE
- SPEED/FLAPS SCHEDULE: VREF30=135 F5=155 F1=175 UP=195 CLEAN=215

[763 jock]

You would just go from 20 to 5. You can call for flap 5 at 155 as long as the aircraft is accelerating. Easy with speed tape, use the "F" speeds.:ok:

[reverserunlocked]

Ah, ok. Cheers for that. Okay well let me run this past you - on a short runway like JSY the perf calculator gives a F20 takeoff presumably to give you the shortest possible takeoff roll. Fiddling with the figures gives different results, so a lower flap setting or less derate gives a longer roll and less margin. Would you simply look at the biggest possible safe derate and run with that or would you, bearing in mind the nasty weather and short runway, sacrifice some derate for a bigger margin? Here's the F20 table for EGJJ with various derates.

** FLAPS 20 ** TO ** WET **
** AIR COND ON ** ANTI ICE OFF **

ASSUMED TAKE-OFF WEIGHT 119439 KG
------------------ FULL THRUST -------------------
0C 152581 FIELD 106-118 118 129 502M 104.7%
---------------- REDUCED THRUST -----------------
+56C 122802 FIELD 114-116 122 129 138M 91.3%
+57C 122013 FIELD 115-116 122 129 120M 91.1%
+58C 121209 FIELD 115-116 122 129 102M 90.9%
+59C 120341 FIELD 115-116 122 129 82M 90.7%
//+60C 119474 FIELD 116 122 129 59M 90.6%
+61C NOT AUTH
+62C NOT AUTH

[mustafagander]

What does the magic box say abut F15 for T/O?

I did a few F15 off short fields but never even heard of F20. AFAIK my lot aren't certified for F20 T/O.

With a F15 T/O we retracted to F5 almost immediately at the end of 2nd segment, thence as per normal.

[411A]

I did a few F15 off short fields but never even heard of F20. AFAIK my lot aren't certified for F20 T/O.


Yes, but some others may well be.
As usual, it depends.
At one airline in the past, pilots always used flaps 10 for takeoff (in the trusty L1011)...and then were astonished to learn that other airlines were using...4/18/22...and even 27 flap, for takeoff.
All, in conformity with the manufacturers AFM data.

Gosh...what an absolute surprise.:\

[Georgeablelovehowindia]

411A, once upon a time, after several days of fog at Jersey (EGJJ) and a backlog of passengers, somebody had the bright idea of sending a TriStar. The fleet management delved into the performance manual, it all looked like a jolly good wheeze, so they loaded up and off they went.

It worked a treat, no probs with the landing, taxy in and park. At which juncture it was found that the steps couldn't be wound up high enough to reach the doors!

:ouch:

[411A]

At which juncture it was found that the steps couldn't be wound up high enough to reach the doors!


We have had this exact problem at a couple of airports in the past, however...a telephone call to the local fire brigade, and presto...a suitable ladder was suddenly presented.
A small charge was paid...so I was told.:}

[rogerg]

Sounds like Freddie Laker>

[DooblerChina]

Reverse, we would run perf for the highest reduction, i.e. lowest cost everywhere. However, at somewhere like JSY, this may well be over-ruled to add safety margin. Dropping a bit of extra flap would be sensible.

DC