mpvincent
Topic Author
Posts: 10
Joined: Wed May 18, 2011 3:47 am

### Impact Of Gradient On Takeoff And Landing B777

Hi there

Does anyone have a rough equation I could use to estimate the improvement in takeoff payload of a b777 200er off a runway that is descending and ascending by a certain gradient? I was thinking if I used the Boeing curves from airport manual to work out max tow and then used some relationship between gradient acceleration and velocity to work out how much more speed I would have with a gradient and then back calc to give implied payload?

Unless someone has some take off curves for the 200er varying by gradient?

Thanks.

mandala499
Posts: 6467
Joined: Wed Aug 29, 2001 8:47 pm

### RE: Impact Of Gradient On Takeoff And Landing B777

 Quoting mpvincent (Thread starter):I was thinking if I used the Boeing curves from airport manual to work out max tow and then used some relationship between gradient acceleration and velocity to work out how much more speed I would have with a gradient and then back calc to give implied payload?

Hmmm... that would be a bit more difficult than just looking at some dispatch tables from the FCOM.
Get the runway length, then put in gradient correction and wind correction to get the "corrected runway length", pull that runway length onto a take off vs TOW table and get the max number for that corrected length.
When we're talking about runway length, the TOW is primary weight limit... then, you can calculate the payload from that (if you know how much fuel is on board).

 Quoting mpvincent (Thread starter):Unless someone has some take off curves for the 200er varying by gradient?

You're in luck in that it's a sunday today and I just did this for fun (    ), so take it as is and no implications that it is correct (but I did take the numbers from a 777-200ER FCOM performance dispatch section).

Gradients are in percent... + means upslope, - means downslope.

Enjoy,

Mandala499
When losing situational awareness, pray Cumulus Granitus isn't nearby !

mpvincent
Topic Author
Posts: 10
Joined: Wed May 18, 2011 3:47 am

### RE: Impact Of Gradient On Takeoff And Landing B777

Thanks very much.

Cheers

### Who is online

Users browsing this forum: 817Dreamliiner, gloom, greg85, johns624, lvs, SheikhDjibouti and 32 guests

### Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos