A320 In-flight actual landing distance

[Gryphon]

I am confused about the new QRH (In flight) Landing distantance tables (ALD).

Why have been they so significantly increased from previous QRH?

Let's keep it simple:

Landing distance without autobrake-Conf. Full-Runway Dry-66t-ISA-No wind-Sea level-No reversers- No C.G. correction.

Previus QRH: 890m.

Current QRH: 1080m

21% extra?

New test flights and certification?:confused:

[tom775257]

Talpa-arc trying to give more realistic line pilot figures for landings with/without failures. The previous were test pilot figures, we are not test pilots.

That said, failures like G+Y failure make runway choice a bit of an issue. I think there has to be an element of airmanship about the use of these distances. Would you fly around on the blue system for an extended period of time with GY fail to find a runway that suited? I know I would find the longest runway with ballpark length close by and go into 3 reds shortly before landing.

[safetypee]

See the thread on Operational Landing Distance - http://www.pprune.org/tech-log/498034-new-landing-distance-calculations-airbus.html

Perhaps the 21% addition is warranted by safety concerns identified in recent landing accidents.

[Gryphon]

Agree, but from FCTM:

"The actual landing distance (from 50 ft above the runway surface until the aircraft comes to the complete stop) is measured during specific flight tests for the certification of the aircraft. This distance represents the absolute performance capability of the aircraft. It is published without safety margin under the name "LANDING DISTANCE WITHOUT AUTOBRAKE" in the QRH.
The flight crew checks this actual landing distance against the Landing Distance Available (LDA) of the runway used for landing applying the relevant safety margins.
The safety margins to be applied depend of the circumstances according to:

• the Captain judgement
• the Airline policy
• the applicable regulations

Note: For example:
The US-FAA recommends to apply a minimum safety margin of 15 % between the actual landing distance and the Landing Distance Available (LDA) in case of

• in-flight determination of the landing distance
• normal and abnormal conditions (except in an emergency)"

Are you telling that Airbus has took care of these "safety margins" and no need for crews to take care of them anymore?

[Gryphon]

Furthermore, I am not talking about the method (Actually I prefer the new one, except that I don't know how to proceed with the "old multiple failures cases") but talking about the results: If no errors, figures have to be the same, whatever the way we use to find out them, unless we are looking for different things, and my question is:

Are we now looking for a different In-flight Landing distance concept (ALD) compare to the former tables or is there any error in the figures before, or perhaps is it my fault?

[PantLoad]

Well, the landing distance numbers have been published based on a test
pilot(s), crossing the fence at exactly 50 feet, at exacty Vref (Vls), very little flare (firm landing.....what I was known for :> :> :>), and standing on the
brakes....maximum braking. The aircraft comes to a complete stop....and some guy gets out the tape measure....measuring from the runway threshold to the nose gear. (I guess it's to the nose gear?????) Any different technique in landing, and the published landing distance figures are out the window.

The FAA and NTSB, really aftter the Southwest accident in Midway, decided we pilots need "realistic" numbers upon which we base our decisions. Example: gusty crosswinds...well, we usually add a knot or two to our approach speed for that...well, that adds to the landing distance. Oh, we flare a bit longer than we should to get a little smoother landing....well, that skews the landing distance numbers, too. Or, we don't stand on the brakes, or use auto-brake....well, that adds to the landing distance numbers. Brakes, tires, runway surface not quite up to par....again, longer landing distance.

Personally, I like what I see. Being retired, I don't use the new system. So, my opinion is meaningless.

Fly safe,


Pantload

[9.G]

Gryphon, have you really ever stopped within 900 m with an airbus on a normal day? Think about it. :ok:

[safetypee]

Gryphon; “Are we now looking for a different In-flight Landing distance concept (ALD) …”
The Operational Landing Distance (OLD) concept is designed to replace the previous ‘actual landing distance’ advisory tables. There is a brief explanation in http://www.multimedia-support.net/flight-safety-conference/docs/21-4-1.pdf

Airbus also refers to Factored OLD (FOLD) which appears to include a further 15% margin; this and other assumptions should be carefully checked on the chart to be used.
Even with the revised distances of OLD / FOLD, crews should still assess the landing conditions and include further factors for the accuracy of the runway condition report, higher approach speeds, threshold crossing height, and the degree of use of brakes and reverse.

Also see http://www.ukfsc.co.uk/files/Safety%20Briefings%20_%20Presentations/Airbus%20Safety%20First%20Mag%20-%20August%202010.pdf
And Safety First 12 (http://www.scribd.com/doc/62707861/Safety-First-12)

[Gryphon]

Thanks a lot Safetypee :ok: