BA84
Topic Author
Posts: 184
Joined: Thu Aug 05, 2004 2:36 am

Heavy Take-off With Tailwind

Sat Oct 28, 2006 3:02 am

Obviously these guys know their airplane intimately, but of course, the passengers are oblivious. Is this done by European or NA carriers? Pilots, come in.....


View Large View Medium
Click here for bigger photo!

Photo © Sam Chui
View Large View Medium
Click here for bigger photo!

Photo © Sam Chui

 
futurecaptain
Posts: 1918
Joined: Sat Sep 09, 2006 1:54 am

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 3:17 am

We try not to t/o or land with a tailwind, but in some cases it is not possible. Although with the wind 090/15 as the photographer says I probably wouldn't have used runway 27. But then again, I dont fly planes burning gas at a rate of thousands of pounds per hour either.

For example, in a C-152 you increase your t/o distance by 10% for every 2 knots of tailwind. If a similar formula is used for heavies (someone else can chime in here) then you could simply run out of runway with a strong enough tailwind.
AirSO. ASpaceO. ASOnline. ASO.com ASO. ASO. ASO. ASO. ASO.
 
heliflyerPDC
Posts: 113
Joined: Thu Sep 21, 2006 6:16 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 3:20 am

I believe that take-off with tailwind is NOT allowed. It obviously dangerous. Probably these pilots had something of a "weight and balance "issue. (but of course I don't know the real circumstances)

I hope it helps.
grtz PDC
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 3:32 am

Not a pilot, but a dispatcher, and tailwind takeoffs are done in some cases.

Each aircraft has its own specific values, but generally speaking, most aircraft are limited to a max of 10 knots of tailwind on takeoff. It helps greatly to have ample runway to do so, since a tailwind takeoff has the same effect as shortening the runway, which results in a lower maximum takeoff weight, and one sometimes lower to the point where one has to leave folks behind.

Many times, tailwind takeoffs will be used so the aircraft departure path is over area-A versus area-B, and you ususally see this for late night ops and/or noise abatement. Should the surface winds increase such that the tailwind component exceeds what the aircraft can do, they'll switch the runways around where aircraft are again operating into the wind. That's supposed to be the way it works, and usually does, but human compliance is another issue entirely.

Now, as far as the comments in Sam's photos are concerned, I have no idea what the max tailwind is for a IL-86 takeoff. That said, lifting off so close to the end of the runway, you "wonder" if they'd have had enough runway to stop had they aborted the takeoff.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
heliflyerPDC
Posts: 113
Joined: Thu Sep 21, 2006 6:16 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 3:36 am

I didn't know that its alowed. Thnkx for the info

grtz PDC
grtz PDC
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 6:46 am

Sometimes a tailwind takeoff is less restrictive, depending upon what lies beyond the end of the runway.
Proud OOTSK member
 
User avatar
Starlionblue
Posts: 17083
Joined: Fri Feb 27, 2004 9:54 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 8:30 am

Quoting HeliflyerPDC (Reply 2):
I believe that take-off with tailwind is NOT allowed. It obviously dangerous.

As has been explained, tail wind take off are allowed under certain circumstances. Limiting factors are windspeed and direction, runway length and max tire speed.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
vikkyvik
Posts: 11799
Joined: Thu Jul 31, 2003 1:58 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 8:51 am

Quoting OPNLguy (Reply 3):
Now, as far as the comments in Sam's photos are concerned, I have no idea what the max tailwind is for a IL-86 takeoff. That said, lifting off so close to the end of the runway, you "wonder" if they'd have had enough runway to stop had they aborted the takeoff.

Not to mention, at least in the US, I believe you have to be at least 35 feet above ground by the end of the runway (if there's no stopway or whatever). Don't know if the FAA would pay you a visit if you weren't, or what.

~Vik
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
Goldenshield
Posts: 5005
Joined: Sun Jan 14, 2001 3:45 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 9:56 am

Quoting Vikkyvik (Reply 7):
Not to mention, at least in the US, I believe you have to be at least 35 feet above ground by the end of the runway (if there's no stopway or whatever). Don't know if the FAA would pay you a visit if you weren't, or what.

For turbine-engine powered transport planes certified in the U.S. after September 30, 1958, takeoff performance calculations must ensure that the aircraft can takeoff and climb out over a clearway past the the end of the runway. The clearway is defined as an extended area beyond the runway 500 feet wide with a grade of 1.25% where no object, except for approach lighting 26" high or less, may extend.
Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
 
vikkyvik
Posts: 11799
Joined: Thu Jul 31, 2003 1:58 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 10:21 am

Quoting Goldenshield (Reply 8):

For turbine-engine powered transport planes certified in the U.S. after September 30, 1958, takeoff performance calculations must ensure that the aircraft can takeoff and climb out over a clearway past the the end of the runway. The clearway is defined as an extended area beyond the runway 500 feet wide with a grade of 1.25% where no object, except for approach lighting 26" high or less, may extend.

Please correct me if I'm wrong, but my interpretation of the previous paragraph is that as long as your wheels are off the ground by the runway end, you can climb at a grade of 1.26% and be legal. Is that correct?

Also, is the approach lighting height supposed to be 26 feet, as opposed to inches?

Lastly, is there a distance from the end of the runway to which the clearway extends?

Thanks for your input, Goldenshield.

~Vik
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
lowrider
Posts: 2542
Joined: Wed Jun 30, 2004 3:09 am

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 10:41 am

Quoting Vikkyvik (Reply 9):
Please correct me if I'm wrong, but my interpretation of the previous paragraph is that as long as your wheels are off the ground by the runway end, you can climb at a grade of 1.26% and be legal. Is that correct?

Depends upon the climb segment. If memory serves, the first segment goes from rotation to 35 feet agl, and only a positive rate, with one engine inop, must be maintained. Second segment goes from 35 feet to 400 feet agl, and a 2.4 percent climb grade must be with one engine inop. In the third segment I think the required grade drops to 1.2 percent and it must be maintained to a height which clears all obstructions or 1500 feet, which ever is higher, and the final segment is for acceleration and clean up. It has been a while since I looked at my notes for this, so I won't swear to the numbers. To tell the truth, I just did a quick search for them and can't lay my hands on them at the moment. But in general terms, that is how the take off profile goes.
Proud OOTSK member
 
broke
Posts: 1299
Joined: Wed Apr 24, 2002 8:04 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 5:14 pm

The runway at La Paz, Bolivia has a 2% gradient. No matter which way the wind is blowing you takeoff going downhill. The takeoff I experienced from the jumpseat was a pip!!
The tower called out an 8 knot tailwind, but the windsock was straight out!!
At sea level that translates to about 15-20 knots. La Paz is at 13,500' above sea level.
So off we went downhill and the airspeed didn't do anything for about 3,000' and the approach lights at the other end came up awfully fast and awfully near to us as we went over them.
Not a takeoff for the white knuckled passenger!!  Smile
 
User avatar
zeke
Posts: 9848
Joined: Thu Dec 14, 2006 1:42 pm

RE: Heavy Take-off With Tailwind

Sat Oct 28, 2006 8:14 pm

Quoting BA84 (Thread starter):
Obviously these guys know their airplane intimately, but of course, the passengers are oblivious. Is this done by European or NA carriers? Pilots, come in.....

That is runway 27 at Phuket, it has an offset ILS, it is the preferred runway for takeoff and landing.

RW 09 only has a non precision approaches, and a hill on the takeoff path. The ILS on RW 27 is offset to avoid that hill.

RW 27 is downhill, with nothing but ocean for miles and miles.

Quoting HeliflyerPDC (Reply 2):
I believe that take-off with tailwind is NOT allowed. It obviously dangerous. Probably these pilots had something of a "weight and balance "issue. (but of course I don't know the real circumstances)

Most jets that I know of are certified for takeoff with 10kt of tailwind. I can think of a number of airports that are normally only allow takeoff and landing in certain directions, where either tailwind on landing or takeoff happens.

Quoting Vikkyvik (Reply 7):
Not to mention, at least in the US, I believe you have to be at least 35 feet above ground by the end of the runway (if there's no stopway or whatever). Don't know if the FAA would pay you a visit if you weren't, or what.

Screen heights are more to do with one engine inoperative situations, and the screen height changes with the condition of the runway, it is lower for a we runway.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar

Who is online

Users browsing this forum: FAST Enterprise [Crawler], Starlionblue and 13 guests