Originally Posted by Expressflight
Surely it is incorrect to say that unfactored LDAs can be used within JAR-OPS legislated operations?
In an emergency, perhaps, but not in the course of normal line flying which is what you seem to be suggesting
You and Alf bring up an interesting point.
I must admit I’m not able to positively confirm my position and don’t have at hand all the necessary documentation.
JAR-OPS as I believe any other country or joint countries regulation follow ICAO directives included in Annex 6: Operation of Aircraft
But "ICAO Standards do not preclude the development of national standards which may be more stringent than those contained in the Annex" So, differences may exist.
For sure, as both of you mentioned, in case of an emergency, the concept of
Required Landing Distance no longer applies, but it’s also the case "for an aircraft system failure occurring in flight and affecting the landing performance" ref. FCOM, and many aircraft system failures occurring in flight are not emergencies.
Now, if I refer to the normal operation, it’s not exceptional especially during winter that a runway condition deteriorates. The procedure is simply to assess the landing distance based on the actual conditions. The charts used in flight provide only
Actual Landing Distance and don’t make mention of any rule to add a percentage factor.
The only notes are:
The provided distances are given for use in flight
No margin is included in this distance
So, the BIG factor is … Pilot Judgment – Correct Assessment of the Situation – Decision Making !
But I agree, don’t push your luck.
Even there, whatever your percentage factor, from nil to 100%, if you overrun, your FDR CVR will be … Analyzed !
Originally Posted by alf5071h
Re good preparation and second a stabilized approach; I agree the need, but as to achieving a stabilized approach at TUG in a tailwind, this should be possible - if the aircraft cannot be stabilised in the conditions then perhaps the approach should not be flown
Thanks to Utube I’ve seen now a few approaches there from the flight deck, and it seems to be a regular occurrence to hear the "SINK RATE" GPWS CAUTION in very short final.
I don’t know what kind of rate of descent it can represent especially with a tailwind, but anywhere else it would be a criteria of unstabilized approach and probable associated GA, but in TGU it’s almost like a requirement.
I had a look at your reference "CS 25 / FAR 25" and all I could see was:
The landing distance data must include correction factors for not more than 50 percent of the nominal wind components along the landing path opposite to the direction of landing, and not less than 150 percent of the nominal wind components along the landing path in the direction of landing
To be honest, I’m not sure what it means … Regulations are sometimes obscures not to say most of the time, at least for me.
But from the ICAO documentation, I’ve found the following reference, which makes more sense:
When calculating the landing weight in accordance with paragraph (b), the certificate holder shall take account of not more than 50% of the reported headwind component or not less than 150% of the reported tailwind component
The way I understand it is:
If the forecast tailwind for arrival time is 10kt the dispatch should calculate the
Requested Landing Distance with a tailwind of 15kt …