Accel and stop charts

[n2o2diver]

Not sure if this is just particular to Piper Aircraft

Question

Why do twin engine aircraft AFM's have accel and stop charts and single engine aircraft do not.

Answer

???

Seems like it would be good info to know regardless of the number of engines. Would like to hear what some of you guys n gals think?

[SteveC]

Accelerate-stop is typically used in conjunction with accelerate-go data to help make planning decisions for twins. I.E., is the runway of intended use long enough to either stop after losing an engine, or safely continue the take-off?

The only thing you would learn with accelerate-stop for a single is whether or not you would be able to stop on the remaining runway if you lose the engine precisely at one particular speed. While this may be marginally useful information for an aborted take-off, it really does very little for you in any other way since there is no decision to be made about continuing the flight after engine loss in a single, eh?

At least that's my take on it....

[Brandon]

edited: I'm too slow this morning....would have been much easier to do this

With a twin engine you have a choice whether to abort or continue a takeoff if you lose an engine. Accelerate stop distance is required for calculations of balanced field length, V1 etc.
With a single engine, you don't have much choice if you lose an engine!

[kellwolf]

Also in a SE you generally don't have to worry about accelerate stop distance unless you're taking off from a 1000' runway. You normally still have plenty of runway when you hit Vr in single engine.

[B767Driver]

[ QUOTE ]
Not sure if this is just particular to Piper Aircraft

Question

Why do twin engine aircraft AFM's have accel and stop charts and single engine aircraft do not.

Answer

???

Seems like it would be good info to know regardless of the number of engines. Would like to hear what some of you guys n gals think?

[/ QUOTE ]

Check out FAR 23.1587, Certification of Norm, Util, Acro & Commuter Cat Aircraft, Performance Information. Some of these charts are regulatory. Interesting enough, the regulation states that multiengine aircraft 6000 pounds or less do not have to have accelerate/stop or go performance charts. They only have to have the rate of climb (or descent) calculated.

A quick check of my Beech 76 manual shows both accelerate stop and accelerate go charts included. Same with the Baron (same manufacturer). My Aerostar manual only has accelerate stop charts. All of these aircraft are under 6000# and do not require either. The manufacturers must have decided to include some limited info for the POH.

[BobDDuck]

The 6000 pound number also comes into play with a positive single engine rate of climb. Part 23 (where all this good stuff comes from) states that (and I don't quote because my FAR is at the office) that aircarft weighing less then 6000 pounds or with a Vso less then 61 knots do not have to demonstrate a positive single engine climb at any altitude or configuration. Anybody know up to what altitude aircraft heavier then 6K are required to show positive SE performance? I can't find that anywhere.

Ethan

[B767Driver]

[ QUOTE ]
The 6000 pound number also comes into play with a positive single engine rate of climb. Part 23 (where all this good stuff comes from) states that (and I don't quote because my FAR is at the office) that aircarft weighing less then 6000 pounds or with a Vso less then 61 knots do not have to demonstrate a positive single engine climb at any altitude or configuration. Anybody know up to what altitude aircraft heavier then 6K are required to show positive SE performance? I can't find that anywhere.

Ethan

[/ QUOTE ]

Reference Part 25.111 thru 25.125. This defines the takeoff and net takeoff flight path. Part 121 defines enroute driftdown requirements (or the requirement to maintain altitude/climb enroute).

Basically, the aircraft needs to demonstrate a positive rate of climb from liftoff to gear retraction (1st Segment Climb). From gear retraction to acceleration altitude (400' to 1000') two engine aircraft must demonstrate a 2.4% climb gradient, 3 engine aircraft a 2.7 % climb gradient (2nd Segment Climb). Thereafter, thru the end of the takeoff profile the aircraft must demonstrate a climb gradient of 1.2%