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jess-b
11-19-2014, 10:05 AM
Hi guys,

I'm having a bit of an issue with tailwinds and climbs. On a few flights where I've picked up a tailwind after departure, as the aircraft has climbed, my airspeed has begun to degrade past my set level. By the time I get close to my cruise altitude, the speed has decreased to such an extent that TOGA LK or A. FLOOR. Protection kick in and I begin to struggle to maintain standard flight. Once I've wrestled her up to my cruise level though, the speed slowly picks up and the flight returns to normal.

Any idea why this is happening? I'm using P3D V2 and ASN for weather.

best wishes,

Jess B

Stephan Schwarz
11-19-2014, 05:27 PM
just a thought: TOW too high? Weight/Balance checked? How do you configure your fuel, pax and cargo?

regards,
Stephan

OmniAtlas
11-19-2014, 09:10 PM
Make sure you have Winds (I think it was autowinds correction) disabled in FSUIPC

I had this issue and once corrected in FSUIPC I could climb again.



Hi guys,

I'm having a bit of an issue with tailwinds and climbs. On a few flights where I've picked up a tailwind after departure, as the aircraft has climbed, my airspeed has begun to degrade past my set level. By the time I get close to my cruise altitude, the speed has decreased to such an extent that TOGA LK or A. FLOOR. Protection kick in and I begin to struggle to maintain standard flight. Once I've wrestled her up to my cruise level though, the speed slowly picks up and the flight returns to normal.

Any idea why this is happening? I'm using P3D V2 and ASN for weather.

best wishes,

Jess B

jess-b
11-20-2014, 12:04 PM
Ok, thanks for the replies guys.

I'm re flying the same flight as yesterday, complete with the same weather. The aircraft is 2000+kg underweight and nothing is selected in the Fsuipc window regarding winds. Now as I cross the DVR VOR departing EGLL, my winds were 260/22 and I was jut passing fl200. Sure enough, the speed starts bleeding away and by the time I reach fl300 I'm struggling to maintain a managed climb. Even switching to selected climb and slowing my V/S to just 700fpm does little to stop the speed from slowing. I'm now hoping I'll reach my cruise level before the TOGA LK kicks in.

Jess B

OmniAtlas
11-20-2014, 07:53 PM
Go to FSUIPC -> Winds

Make sure 'Smooth wind changes near aircraft' is disabled.

jess-b
11-20-2014, 08:05 PM
Nope, nothing checked in the winds section. The only solution is to slow my rate of ascent to nearly a crawl and let the speed build back up. Very unusual.

Best wishes,
Jess B

jeehell
11-21-2014, 06:18 AM
Hi,

There are some weather addons which mess up the temperature profile.
What OAT/TAT do you get at various FL during your climb?
Also, even if obvious, you do not have spoilers or gear extended?

Regards,
JL

BushPilotWannabe
11-21-2014, 12:58 PM
Have you tried descending on a reciprocal heading?

jess-b
11-21-2014, 05:59 PM
Hi Jean Luc,

reflying the flight again to confirm the issue. Here are the stats as they stand.

Just passed over DVR at fl250. Winds 264/26
GW 63122
TAT -9c
SAT -36c

cost index - 35
cruise level FL350
expected speed 318/.077
current speed 310kts/.753 decreasing
V/S -2500 managed mode.
GS 477
TAS 452

weather by ASN set to historic mode (just to keep conditions the same as the original flight.

Any ideas?

edit: switching to selected mode with an op climb, the aircraft seems much happier. In fact as she climbs she's slitghtly overspending past her set speed. Go figure!

Edit again. Reselecting managed mode climb seems to reset everything. Aircraft now happy as beer drinker in ocktoberfest.
Jess

jess-b
11-25-2014, 09:14 AM
Quick update.

Just run a flight that had a tailwind on the climb, and now the aircraft behaves impeccably. Not sure if you've changed anything Jean Luc in the last two updates, but everything's running sweetly.

Best wishes,
Jess B

jeehell
11-25-2014, 11:17 AM
HI,

No I did not change anything in that direction. I guess it's an oddity with weather addons...

Regards,
JL

jess-b
11-29-2014, 06:48 AM
Hmmm, ok. I'll re fly my test flight without any weather just to test whether the issue is me, as opposed to the weather engine.it maybe my operation of the systems is off somewhere.

Jess