Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
V1 Speeds Out Of A Speedbook  
User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Posted (5 years 2 months 1 week 3 days 13 hours ago) and read 3967 times:

How come V1 speeds are depicted in speedbooks as a function of TOW only, shouldn't the length of the actual runway used play a part in figuring out the appropriate V1? Do the tables just assume accelerate-stop distance = take-off distance at that particular weight?


LY744.


Pacifism only works if EVERYBODY practices it
5 replies: All unread, jump to last
 
User currently offlineGoldenshield From United States of America, joined Jan 2001, 5845 posts, RR: 15
Reply 1, posted (5 years 2 months 1 week 3 days 11 hours ago) and read 3937 times:

The actual runway length IS is used to determine V1. However, it is only a baseline V1. Other factors, such as runway slope, wind, etc., will influence V1.

Of course, for the purpose of this topic, the number in the flip books are all based on weights, as the maximum weights for the flight (which includes maximum takeoff weight for a given runway, 2nd segment climb, enroute driftdown, and maximum landing weight) are figured out during the pre-flight planning stage. And to answer your second question, ASDA is NOT used for takeoff distance, but rather the takeoff distance required is 115% that of the takeoff runway distance available where the plane must reach a minimum of 35 feet above the runway plane.

That's with U.S. regs. Other counties may vary.

[Edited 2009-02-08 14:46:12]


Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 2, posted (5 years 2 months 1 week 3 days 7 hours ago) and read 3870 times:



Quoting LY744 (Thread starter):
How come V1 speeds are depicted in speedbooks as a function of TOW only, shouldn't the length of the actual runway used play a part in figuring out the appropriate V1?

If you have more runway than you need for a balanced-field takeoff, you can take it into account. Then it's an improved climb takeoff. That's usually done via computer, not by books.

Quoting LY744 (Thread starter):
Do the tables just assume accelerate-stop distance = take-off distance at that particular weight?

The normal approach is accelrate+RTO distance = accelerate+single-engine takeoff distance. That's the normal definition of a balanced field takoff...this is why airplanes almost never use the whole takeoff-distance-required length (the accelerate+two-engine takoff is shorter than either of the balanced field lengths).

When you throw all the other regulations in there, you may be limited by something other than the balanced field length (e.g. V1 can't be higher than VR, you may have an engine-out climb gradient limit, an obstacle limit, V1 can't be lower than Vmcg, etc.).

Tom.


User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 3, posted (5 years 2 months 1 week 2 days 18 hours ago) and read 3801 times:

Alright, I threw a spreadsheet together and I see what you guys are saying. Thanks!


LY744.



Pacifism only works if EVERYBODY practices it
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 4, posted (5 years 2 months 3 days 9 hours ago) and read 3544 times:



Quoting Tdscanuck (Reply 2):
That's usually done via computer, not by books.

Improved climb (overspeed takeoff) speeds are available in the AFM (on Lockheed and Boeing airplanes) if one cares to look.

Also, on specific runway analysis charts.

'Computer' not necessary...only an ability to read and understand.


User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 5, posted (5 years 2 months 3 days 6 hours ago) and read 3524 times:



Quoting 411A (Reply 4):
Improved climb (overspeed takeoff) speeds are available in the AFM (on Lockheed and Boeing airplanes) if one cares to look.

True, but I've never seen or heard of the AFM being used to do an improved climb takeoff calculation in normal commercial service. It's either the FMC, the EFB, or dispatch using a software tool.

Tom.


Top Of Page
Forum Index

Reply To This Topic V1 Speeds Out Of A Speedbook
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
How Fast Does Air Travel Out Of A Turbofan? posted Tue Oct 7 2008 21:38:31 by Triebwerk
Very Steep Turns Climbig Out Of PUJ. posted Thu Jun 12 2008 12:40:51 by Mastropiero
Gulfstream Takes The Wire Out Of Fly-by-wire posted Mon May 26 2008 05:01:07 by Aviationbuff
Did This Aircraft Just Drop 1000 Feet Out Of Sky? posted Sat Apr 5 2008 13:07:06 by Boston92
747-400ER Out Of MEL posted Thu Apr 3 2008 14:43:52 by WunalaYann
Out Of Country Flight Crews posted Thu Apr 3 2008 11:04:52 by AFKLMLHLX
Tu-154 Conception Of Out-of-fuselage Gears posted Sun Mar 23 2008 00:19:01 by AcroAirFun
Which BMIbaby Aircraft Out Of EMA? posted Mon Mar 3 2008 12:17:38 by EMAlad
Something Leaking Out Of SF3 Engine posted Wed Dec 5 2007 20:23:28 by Halophila
ATR Backing Away Out Of Parking Position posted Thu Nov 29 2007 08:19:41 by Konrad

Sponsor Message:
Printer friendly format