use of reverse?

[inbalance]

Those added 42% runway length are there for when things go pear-shaped.
Imagine a slightly damp runway, where there are rubber smears remaining on the first third of the RW from people braking hard (not unusual on short runways). Now you will suddenly find your braking action is all but gone. Then use full reverse and with a little crosswind, you may wander off into the grass.

Never base your numbers so that it will barely work when everything goes right. Aviation history is littered with bodies who relied on nothing going wrong.

OOR: I know what you want me to say.

I shall calculate for the worst case.

So whats the worst case? No reverser and no brakes !!!!
I donīt have a Graph for that in the books, so what?
Guess it? I think I would need about 6000 or maybe 7000 ft Runway with both US.

Shall I plan into 7000 ft Runways only ??


No, thats not what I am going to do.

I fly FAR 23 Aircraft comercial since 1992. Since 1995 as a Captain. We are opreating under JAR-OPS 1.
I donīt need somebody to tread me like a schoolboy telling me that the runway may slippery.
I told you, that I can stop without reversers within 3000 ft.
With reversers working it will be 2500 ft only.
The runway I am planning to land at, has to be 3550 ft long.
So plenty of reserve for me.

The next thing is, all the landing data is based on overflying the treashold at 50 ft.
All this small airfields are VFR. I donīt follow a GS there, wich will bring me just 50 ft over the treashold, leaving 1000 ft of good runway behind me when I touch down. Without this 50 ft, touching at the threashold, I need 1700 ft landingdistance only, with brakes and reversing.
No Rubber of hard braking pilots at the treashold, because they all overflying at 50 ft.
Pilots touching at the beginning of the runway donīt need to brake hard.

I know, that planning my aircraft with reversers and JAR-OPS 1 additionals are safe for me.
AND I KNOW I HAVE TO ADD ANOTHER 15% IF THE RUNWAY IS WET.
All I was asking here is:

Can I legaly do it, or is there any law against it.


regards

Inbalance

[OutOfRunWay]

My apologies, inbalance.

I've just noticed on rereading the entire thread that I missed your initial post and did not understand the original issue.

In answer to your original question - I cant find it either, but I think I know who to ask. I may be back with an answer.

Regards, OORW

[mutt]

If the data is in the AFM, you can do it without question, if its in the AOM, you can approach your authorities and seek permission.

Mutt

[411A]

The next thing is, all the landing data is based on overflying the treashold at 50 ft.
All this small airfields are VFR. I donīt follow a GS there, wich will bring me just 50 ft over the treashold, leaving 1000 ft of good runway behind me when I touch down. Without this 50 ft, touching at the threashold, I need 1700 ft landingdistance only, with brakes and reversing.

This might work for your small FAR23 aeroplane, imbalance, but will most definitely not work for larger jets, for when this 'duck-under' is tried with many jet transports, the main landing gear may well become entangled in the approach lights frangible bits, with expensive results.

In any case, the 'duck-under' maneuver has been the cause of several accidents, especially when unpredictable windshear may be present.

I don't suppose that my remarks will be especially appreciated, however, by a few of the more younger pilots, who may well consider themselves ace-of-the-base....for sooner or later, their luck will run out.

[Angels 60]

Imbalance..sorry you have to take comments from anonymous posters questioning your judgement and ability...

Just call the JAA people...give them your SIT REP...

[SNS3Guppy]

For those following along, bear in mind that Angels 60 is the same poster who got the boot as ssg, and Trickle451.

[yrvld]

Try JAR–OPS 1.515 Landing – Dry Runways and following.
Also see if you find anything in AMC OPS 1.510 and 1.515 or search "performance class" in the JAR OPS.

[DFC]

(g) If any device is used that depends on the operation of any engine, and the landing distance would be increased when a landing is made with that engine inoperative, the landing distance must be determined with that engine inoperative unless the use of other compensating means will result in a landing distance not more than that with each engine operating.

I believe that the answer is in the above from post 4.

Reverse depends on the operation of that engine. Without that engine and it's reverse, landing distances will be increased.

How much reverse can you have on the operating engine with the other feathered? If anything it will be limited.

Thus reverse available from both engines is affected by the failure of any one engine.

So you can not use the reverse to claculate the required distances because it "depends on the operation of any engine".

I expect that your aircraft does not have something else to compensate for the loss of revese so unless the certification people have managed to get the figures with reverse approved for normal dry ops and thus in the flight manual, you are stuck with the figures as published.

-------

Just to correct one small point made earlier - the 1.42 factor does not give a 42% safety net.

A 1.42 factor means that you will stop within 70% of the runway leaving 30% of the runway available as a safety net.

Regards,

DFC

[Angels 60]

DFC....I never thought of it that way!..excellent post...yes under single engine ops, reverse on on the bad engine wouldn't be available...how obvious that reverse wouldn't be calculated into landing distances for that reason on many aircraft.

Evidentely, in Imbalance's he has reverse numbers...no plane I ever flew did...nice to have if you need them.

Thanks!

[bobrun]

Here's what I thought....

With no failures, reversers are never taken into considerations when calculating distances. However, with a failure and a wet/contaminated rwy, then reversers must be considered in the distances.

Sounds like some are trying to push the limits a little by reducing the landing distance calculations by all means...perf calculations have evolved from the industry's experience and accidents/incidents records...why not use that wisdom and stick to well accepted policies on how to calculate distances? Even if you find a piece of law that allows you to use reversers in all calculations, it won't really help you once you're in the dirt at the far end of the rwy!