FliFast

For the professors on this message board, here's one:

To determine how much runway is available for landing, I always thought you take the most applicable of the following:

Take the threshold distance and subtract 1000 feet. The threshold is where you are supposed to be at 50 feet. Even though the ensuing air run is approximated to be 850 feet to 1500 feet, you subtract only 1000 feet.

Take the distance listed as landing distance beyond the glideslope. This is applicable when there is an instrument landing system and the aircraft is utilizing this via manual procedures, HUD, or autoland.

Take the distance NOTAM-ed due to a Temp. displaced threshold.

Would someone please add to this post with a definitive answer, thanks in advance.

Where's Lonnie when we need her.

FliFast, and landing slow.

Tarheel

The answer may lie within your aircraft's Flight Manual. My jet’s TOLD calculations take air distance into account when determining landing distance. As long as the published runway avail is equal to or greater than the calculated landing distance, I'm good to go. As long as I touchdown within 800-1300 ft down and brake per the tech order/FM.

I'd look in the FM and see if subtracting 1000' is required or just a technique.

CactusCrew

Who's Lonnie ?

And why did you land long again !





I'm obviously not a "professor" ...

BOYCAPTAIN

Our APLC numbers are based on this

6.27 APLC Landing Performance Calculations

Landing data provided by the APLC assumes that the touchdown point occurs 1500 FT beyond the runway threshold. For example, a total landing distance of 6000 FT (provided from the APLC In-flight Landing Performance module) assumes that the first 1500 FT of the runway will be overflown and the actual rollout distance on the runway surface will be 4500 FT. Touchdowns beyond the 1500-foot point will extend the APLC landing distance by a comparable amount for the planned braking selection. Critical landing operations such as short runways or LAHSO require careful attention to landing performance data as well as precision in achieving a touchdown at the appropriate location on the runway.

EXTW

Lonnie would say, "Ding-Ding!, Ask the question you want answered!" The "runway available" for landing is from the threshold, not the "beyond GS" distance. The "required" runway calculations depend on what your particular aircraft performance numbers are predicated on. Check the AFM/FHB whatever is is called at Brown.


EXTW

FliFast

Thanks Boy Captain...good info.

ExTW, I thought Lonnie always said it was the more applicable of the three on the back of the 10-9 chart...was I asleep for that ???

The question is NOT how much runway does my plane need to land in, I have a fancy computer that will tell me that.

My question is how much concrete do I have to land on. Threshold, beyond G/S, or wait, I remember take the distance on the front of the 10-9 and subtract 1000 in case there is no "back" to the 10-9 page...does that sound right, EXTW ?

Thanks

FF-the Class Ding Ding.

handypilot

first a couple of Definitions:

Landing Distance Available (LDA) - basically, all of the runway starting at the landing threshold, or displaced/relocated threshold if there's and obstacle or construction

Landing Airborne Distance - 50' screen height above threshold to touchdown. this distance varies with weight, wind, descent gradient, etc., but is generally 1000' from the threshold

Landing Ground Distance - touchdown to stopped, and were all familiar with what effects a ground roll.

Landing Distance Required (LDR) - Landing Airborne distance + Landing Ground Distance

In order for a turbo-jet aircraft to land, the mass must be low enough so LDR < LDA x .6 (You need to be able to land in 60% of the LDA) or to put it other terms there is a 66% "Factor" that allows you to float 2000' in order to roll it on to impress the hot flight attendant with the big....................hands!

This is for a dry runway. The rules change when it's contaminated, and there are other things like only 50% of a headwind is considered, but 150% of a tailwind is considered.

Anyway....I would guess that when you compute a LDR using your AFM it includes the landing airborne distance, but Douglas could do things differently. So, when trying to determine how much runway you need, you would include the whole runway (LDA) even though you eat up some of it in the flare, because your LDR calculation includes this.

Clear as Mud!
Handy

Adola

I've always used my shoe size time the OAT in degrees centigrade X 100...and then requested the longest runway!

FliFast

Thanks Handy, actually it does make sense to me.

On the back of the 10-9 page, how does landing beyond the glideslope get factored into this. For example up in ANC if you have that airport diagram.

I think LDR was what I was looking for.

Fortunately, UPS doesn't have F/As with big hands.

Much Obliged,

FF

EXTW

FF,

Informational purposes only I believe.

Last new-hire of '88 Ding-a-Ling.