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Old 14th Apr 2017, 16:54   #1 (permalink)


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Boeing 787/747-8 QRH PI Advisory Information Normal Configuration Landing Distance

Good evening, gentlemen.

Maybe there are some 787/747-8 pilots here.
I have a question regarding QRH PI Advisory Information Normal Configuration Landing Distance.
What is the amount of air distance included into your QRH?
On 737 we have 305m of air distance. I heard that following TALPA ARC recommendations Boeing changed this to 450m on latest developed aircraft 787/747-8. Is it right?
Company I work for is changing policy for inflight calculation of landing distance so this info would be helpful.

Thank you in advance.

P.S. Screenshot from QRH would be much appreciated.
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Old 17th Apr 2017, 05:53   #2 (permalink)
 
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B-747-8 QRH Normal Configuration Landing Distance shows: "Includes an air distance from threshold to touchdown associated with a flare time of 7 seconds."

So Boeing has gone to time, not distance in the -8

We translate this into approx 1500 feet from the threshold.
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Old 17th Apr 2017, 07:05   #3 (permalink)
 
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B.787-8 QRH PI:

"The reference landing distance is the distance from threshold to complete stop. It includes an air distance allowance from threshold to touchdown associated with a flare time of 7 seconds."

Interestingly, the 787-9 QRH-PI does not include this comment!
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Old 17th Apr 2017, 07:30   #4 (permalink)
 
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We have the 7 second comment in both sections (-8 and -9) of our 787 QRH. Its at the bottom of the normal config ldg distance tables.
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Old 17th Apr 2017, 08:09   #5 (permalink)
 
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Oh yes, just saw that too. I was looking in the 'text' section where it does not appear for the -9.
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Old 17th Apr 2017, 17:11   #6 (permalink)
 
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For your interest....

The 744 used to say "Includes an air distance from threshold to touchdown associated with a flare time of 4.22 seconds". Then it changed to just 1500 feet.

4.22 seconds was not very realistic.
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Old 20th Apr 2017, 12:51   #7 (permalink)


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Thank you for your replies, gentlemen.
I downloaded 737 MAX QRH from myboeingfleet.com.
It has "7 seconds of flare distance", as well.
Possibly we are going to have a sort of "+200m tolerance for touchdown" to be in line with latest Boeing developments on our NG's and CL's.
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Old 20th Apr 2017, 15:37   #8 (permalink)
 
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Do remember that these distances are distances flown in ideal approaches, by test pilots.
Average touchdown distances are proven, Industry wide, to be further from the threshold in reality. Something to consider when making landing distance calculations.
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Old 21st Apr 2017, 11:10   #9 (permalink)
 
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Icelanta, your wise caution may not be so relevant in this discussion.
The AFM 'certificated data' (test pilot distance) is generally used with the required factoring for the pre-takeoff assessment, although some operators may use heavily factored distances for in-flight landing distance assessment.
Some manufacturers have published 'actual' data, slightly different from the AFM data (1000/1200ft air-distance, use of reverse), but this also requires careful consideration even with a minimum additional factor (15%).

Following the TALPA initiative, aircraft manufacturers agreed a more realistically achievable (actual) landing distance, commonly known as 'Operational Landing Distance' (OLD), to be published in the QRH etc.
The general basis of the changes are in Safety First page 8. Note the reference to flare distance based on time (7sec) for OLD vs fixed distances for 'actual' data. Thus the discussion appears to relate to the latest standard of data.
Generally when OLD is published it includes a minimum factor and becomes Factored OLD (FOLD).

I believe that all Airbus and Embraer aircraft now use OLD/FOLD (including abnormal config), but for Boeing aircraft this may be limited to new types. Anyone have further info?
Also what do Boeing call this data, how is it titled; how is it differentiated from previous 'actual' data apart from reading all of the small print.

A potential hazard for operators is with operating the same 'type' of aircraft in a fleet, both legacy and new generation aircraft, or particularly for crews with a 'same type' rating (cross fleet operations) implying a mixture of 'actual' and FOLD data - the greater risk being with 'actual' data against the more conservative FOLD.
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