Airline Pilot Central Forums - Runway analysis Landing distance question

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Quote:

Originally Posted by metro-mia (Post 129326)

Our airline's runway analysis has a landing distance for landing beyond threshold and another one for landing beyond glide slope. For each distance it has the corresponding maximum weight allowable for that distance/runway.

My question is, what regulation or Ops Spec or other guidance addresses which landing distance you should use?

My assumption is that if you're on a visual approach, perhaps the beyond threshold distance is usable. If an ILS approach is used, perhaps the beyond glide slope distance is requied. However, we all know that one cannot descend below glide slope until necessary for landing. Is the beyond threshold distance ever permitted?

Any opinions or references to where this might be covered would be great.

Thanks!

Are you not required by regulation in a turbine airplane to remain at or above the electronic glideslope (or visual glideslope, as appropriate) for that runway?

If you are legally required to land at or beyond the glideslope, why would you calculate distance based on a landing prior to that point?

If you're flying an aircraft of any significant size, don't you have a a minimum threshold crossing height and a valid reason to not spot the numbers and land on the threshold?

Landing distance beyond glideslope is what you should be looking at.

Quote:

Originally Posted by metro-mia (Post 129661)

That's what I think as well. Just wondering what the legal "FAA" answer is. :) However, it probably is like most things and depends on the FSDO, POI, region, time of year, airport and who you ask.

Thanks for your reply.

The FAA would probably point you to SAFO19001, this covers all variables.

https://www.faa.gov/other_visit/avia.../SAFO19001.pdf

g. Touchdown Point. The touchdown point used in the performance data assessment reflects the assumed air distance. Operational landing data usually includes an allowance for 1,500 feet or 7 seconds of air distance from the threshold to touchdown. An air distance as short as 1,000 feet may be used IF an operator’s landing assessment procedures include enhancements to minimize the risk of overruns or undershoots, including:

1) Training in touchdown control and short field landing techniques.
2) Identification of required touchdown point and training to assure go-around procedures are initiated if unable to achieve a suitable touchdown point.
3) Approach guidance and runway markings on the specific runway are consistent with a shorter air distance.
4) Operational data (without the need for interpolation) are provided to the crew for the specific runway, conditions, and aircraft landing configuration.
5) The flight techniques assumed in the creation of the performance data used for a shorter air distances are based on flight techniques to be used in the shorter air distance operation.