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-   -   aircraft doomed if takeoffs with maxthrust and encounter windshear? (https://www.pprune.org/tech-log/514127-aircraft-doomed-if-takeoffs-maxthrust-encounter-windshear.html)

dolpinsky 6th May 2013 04:22

aircraft doomed if takeoffs with maxthrust and encounter windshear?
 
what kind of recovery procedures can it apply? :eek:

Dufo 6th May 2013 04:28

Firewall the burners, pitch to stick shaker (up) and that's about it.

Slasher 6th May 2013 04:48

And assuming you're at the max weight applicable for that OAT?

Not necessarily - you're some knots above stick-shaker which
translates into an increase in climb capability. Also your balls
to the wall thrust is most likely higher than what you set on
the EPR or N1 gages.

If its a bad day and you lose a donk in the process....well its
a different story then.

Wizofoz 6th May 2013 04:48

If ANY aircraft ever encounters windshear which is beyond it's ability to out-climb, it's a gonner.

Clearly operating closer to the aircrafts maximum performance gives you less margin- but where do you draw the line?

There are buffers built in to takeoff peformance so even a takeoff needing TOGA thrust leaves excess performance that can be used if needed.

ETA- Post crossed with the Slash, who is correct.

Take-off performance allows for an engine failure- so provided both keep running, you have that much excess performance to counter windshear.

de facto 6th May 2013 05:19

If one encounters such a windshear/downdraft during take off maybe one shouldnt have taken off in the first place....

Uplinker 6th May 2013 08:40

Precisely - there's no 'maybe' about it.



U

Slasher 6th May 2013 08:55

Hell why don't we just stop teaching windshear recovery then.

crash_test_dummy 6th May 2013 09:32

May I also add: no configuration changes until out of WS...

flyingchanges 6th May 2013 13:41

If windshear is anticipated, reported, or likely, one should be using max thrust anyway...

Clandestino 6th May 2013 14:18

If significant windshear is anticipated, reported or likely, I'd be using ground idle thrust at the worst.


what kind of recovery procedures can it apply?
Windshear recovery procedures.


aircraft doomed if takeoffs with maxthrust and encounter windshear?
Depends on windshear severity.

de facto 6th May 2013 14:40


Slasher Hell why don't we just stop teaching windshear recovery then.
Well if id have to chose to be a pax of a pilot who has been trained on windshear recovery and is about to take off into a storm area from which the windshear/downdraft may be over the aircraft performance OR a pilot who has not been trained to windshear recovery but who will delay the flight 30 mins not to take off in such weather,i know behind whom ill take my seat.

EEngr 6th May 2013 14:58

Refer to QRH procedures for "Aircraft Doomed"?
;)

lomapaseo 6th May 2013 15:45

If you already have the engines at max then you can check off that part of the checklist and follow the rest of the items with less worry about spoolup times.

One is not doomed just because they have already met one of the checklist requirements, just carry on with flying

I miss Slasher already

RAT 5 6th May 2013 19:18

aircraft doomed if takeoffs with maxthrust and encounter windshear?
what kind of recovery procedures can it apply?


Bend over, head between legs and kiss your a@Łe goodbye.

FlightPathOBN 6th May 2013 19:54

Polish Dolphin,

Wind Shear encounters happen all of the time on DEP.

Are you talking about Wake Turbulence, Wind Shear, or Microburst encounters?

Tay Cough 6th May 2013 23:02

Depending upon whose operations manual you use, some state that if severe windshear is forecast, DO NOT TAKE OFF.

If it isn't forecast and you encounter it, do as some of the previous posters suggest and you'll have a fighting chance.

blind pew 7th May 2013 17:36

Had it once on a md 80 off 34 zrh..
Not forecast but mate reported it just before we departed - he was airborne off 28.- 23 knots cross.

We lost 30 knots around 1000ft but had a significant temperature increase..which meant we were way outside our take off calculation.
Went firewall and pitch but speed continued to decrease and therefore on the backside of the drag curve.
Skipper ignored my speed calls and with the black forest looming in the darkness I forced the nose down...and we started accelerating. Climb performance slowly returned.
Cause large pool of very cold air over the airfield but a warm front blowing over the top.
Besides one partial report no forecast to stop us going.

bubbers44 7th May 2013 23:48

Windshear is fairly predictable. Once in a while you have to deal with it when unexpected. Just be ready and know how to deal with it. You never use anything but max power with possible wind shear. We did the procedure all the time in the sim, never had it happen in real life.

haughtney1 8th May 2013 06:40

Turn the packs off and get a bit more boost:E

Teldorserious 8th May 2013 15:54

I've hit it twice on landing. Full power, pitch just above stall, engines screaming and the plane is going down. Hit hard both times.

Much of this depends on the severity, your altitude, engine spool up time, and how much excess power you can throw in. A little twin only has so much. A jet that can throw in enough for an initial 10k FPM climb is better.

That said, this is ALL about hand flying by the way. My suspicions are a few guys have stalled the aircraft rather then mush in and take the hit if they have to.


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