777 Landing Performance

[blah blah blah]

Hi all,

Reading through the FCOM etc but not getting an answer to my questions.

Can anyone tell me what exactly the advisory landing distance in the EFB is telling me? Does this include the appropriate factor for regulatory requirements?

Our regulator requires you to stop within 60% of LDA for a dry runway, but the advisory landing distance can be greater than this.

Im guessing the performance requirements can be adjusted for different airline/nation requirements. That said can anyone give me an idea of what the landing calc numbers in the EFB are actually telling me?

Cheers,

Blah

[Wizofoz]

What a particular EFB is programmed to deliver is a user option, so it is whatever your particular Airline requested it to be.

[blah blah blah]

I did think as much. Could someone give me an idea of how it is set up in their company?

Cheers

[bucket_and_spade]

We use the concept of OLD - Operational Landing Distance, it's the new 'thing' apparently!

It's the ALD (Advisory Landing Distance) found in the PI section of the old QRH but has a 15% factor added to cater for us not all being test pilots. This factor sometimes increases to 30% if the conditions dictate (low temp/dewpoint split).

All of this background is in our company manuals.

Hope it helps.

B&S

[8che]

Blah,

Boeing produce only 2 types of information. Advisory and dispatch performance data.

As far as the EFB landing data goes these 2 types are displayed.

The dispatch data page will show max landing weight and quick turn around weight after you put some limited wx data in. It does not show the landing distance required. This is all factored data including 1.67/1.92 etc.

If you press the en-route button you get the more commonly used page which displays landing distance required/available after you put in the landing weight/wind/autobrake etc etc. This is advisory data and is unfactored so it is exactly how the aircraft will perform with no margin for error.

[safetypee]

“… same as … but has a 15% factor added…” #4.
Be very careful with such assumptions. The concept of OLD should provide a more realistic value of the minimum ‘actual’ landing distance that pilots might achieve, and thus OLD may be greater than previous published actual distances (ALD).
It is very important to read the small print associated with the distances which should explain the assumptions made and the conditions relating to the data.

If the data is expressed as Factored Operational Landing Distance (FOLD) – introduced by Airbus, this probably includes the minimum recommended factor of 15% safety margin. Again read the small print, understand the assumptions, and always assess the runway state carefully, being prepared to add a distance margin greater than the minimum or adjusting the braking level etc, etc.

See related item for Airbus and refs http://www.pprune.org/tech-log/513863-rwy-condition-assessment-matrix-ldg.html#post7822808

[blah blah blah]

8che,

Thanks, this is exactly what Im after.

Just to be clear you are saying that the OPT will provide factored data for the dispatch calculation (appropriate to the input of wet/dry rwy), but the enroute data will be unfactored.

This means that when doing an OPT enroute calc I need to add the 1.67/1.92 factor to the advisory landing distance before comparing with the LDA?

I know that this sounds like basic stuff but I cant find any reference to it in the FCOM/QRH/EFB user guide. If someone has a reference from a 777 manual I would very much appreciate it!

Cheers,

Blah

[8che]

Blah,

That's correct (almost). To dispatch you must legally comply with the regulations and so that must include the factors. This is therefore covered before taxi and should be looked after by your ops guys hence it is displayed as a limiting weight on the OPT.
Once flight has started ie "enroute" you only have to safely land with whatever you have so no factors are included in the OPT and it simply displays actual landing distance needed. That means you do not have to apply any factors to the enroute landing data at any stage in the flight and that also includes non-normals when airborne so relax. The enroute page is simply a reproduction of the advisory data in the performance in flight section of the QRH.

Here's 2 extracts from the manuals below; if you want to know more check out this http://www.ifalpa.org/downloads/Level1/Briefing%20Leaflets/Aircraft%20Design%20&%20Operation/12ADOBL03%20-%20Certified%20vs%20advisory%20data%20on%20Boeing%20aircraft .pdf


Dispatch related Landing Info includes landing weight limitation for the selected RWY condition and for the selected aircraft configuration. The associated speed Vref30+5 is displayed. In addition, landing weight limitation for icing and low visibility conditions under the same aircraft configuration is given.

Dispatch related landing information on a DRY runway is based on the "Required Landing Distance" which is 167% of the demonstrated landing distance during aircraft certification.

Dispatch related landing information on a WET runway is based on 115% of the required landing distance on a DRY runway.

Dispatch related landing information on a SLIPPERY and CONTAMINATED runway is based on 115% of the actual landing distance on contaminated runway during aircraft certification OR the required landing distance on the WET runway, which ever is longer.

Quick Turnaround weight and time are included in the dispatch related landing info. If landing weight exceeds the maximum quick turnaround weight for the airport OAT and QNH wait the specified time and check the wheel thermal plugs that they are not melted before executing a subsequent takeoff.

Advisory information-These values are actual landing distances and do not include the 1.67 regulatory factor. Therefore they cannot be used to determine the dispatch required landing field length.

[blah blah blah]

8che,

Thats fantastic! Thanks for explaining and providing the link.

Blah