ATPL Performance

[boltz]

Hey guys,

Just a quick question regarding B727 landing charts. Why do you reduce the landing distance by the greater of 13% of LDA / 300m for a CAT 1 landing?

Thanks

[The Green Goblin]

PFM mate :ok:

[john_tullamarine]

Not sure where your requirement originates .. can't recall it being in vogue during my 727 time.

As stated, it makes little sense at all.

[PercyWhino]

Boltz.

I have recently completed my ATPL Perf and Loading. The requirement of reducing the landing distance by the greater of 13% or 300m for a Cat 1 ILS is essentially because on an ILS the Glideslope flies you down into the touchdown zone which is the 1000 foot markers from the end of the runway (which is basically 300m from the threshold), the idea being that is where you touchdown therefore the runway is effectively that much shorter.
Whereas on any other approach the idea is you can aim your approach to touchdown right on the numbers therefore having full length available.

Tulla

That requirement for adjusting the landing distance by 13% or 300m is in the CASA B727 Perf and operating Handbook, for the CASA ATPL Performance and Loading exam, I dont know if it is a real requirement or not.

I appreciate that an Aircraft of that size it is desirable regardless if youre on an ILS or not to touchdown in the touchdown zone, but it is written in the CASA published 727 booklet that that is what you do therefore that is what you have to do.

Boltz if you have any other questions shoot me a PM and Ill help you out where i can.:ok:


PercyWhino

[john_tullamarine]

.. the Glideslope flies you down into the touchdown zone which is the 1000 foot markers from the end of the runway (which is basically 300m from the threshold), the idea being that is where you touchdown therefore the runway is effectively that much shorter.

Irrelevant .. the LDR is based on overflying the start of the runway at 50ft which makes the 1000ft point the "normal" target.

Whereas on any other approach the idea is you can aim your approach to touchdown right on the numbers therefore having full length available.

Might be OK, physically, for a small aircraft but, for anything of any size, a good way to leave half the aircraft hanging on the fence.

That requirement for adjusting the landing distance by 13% or 300m is in the CASA B727 Perf and operating Handbook

ah, OK. For the exams, you do what the system expects. My time lecturing in the exams was past when they moved to the 727 as the example aircraft.

From a practical point of view, I can see no relevance either to certification or routine operations. CAT 1 is close enough to CAVOK so far as the final flare and touch down is concerned.

[Tinstaafl]

I wonder if CASA has changed the ops requirements for the 727 performance exam? I don't recall a LDR reduction when I did mine in '90 or '91. It could be my memory but AFAIK there was nothing like that when I did it.

[maverick22]

Whereas on any other approach the idea is you can aim your approach to touchdown right on the numbers therefore having full length available.:eek:

Maybe in a lightie, but do this in a transport category aircraft and you'll be having discussions over tea and bikkies with the chief pilot;)

Is it not correct that all landing distance calculations, even for lighties, are calculated based on the fact that the aircraft flies over the threshold at 50 feet?

[PercyWhino]

Correct that it is based on 50 ft down. However the reason i was given for the reduction of either 13% or 300m on a Cat 1 was due to what was mentioned in my previous post.

As far as the exam goes, nearly everyone knows that the exams arent what really happens. For the sake of the exam do the reduction when applicable.

The reason that i mentioned in my previous post was what was explained to me as to why to make the reduction.

I also made mention that an approach should be made to the touchdown zone regardless. Either way an approach on a PAPI or VASI or ILS with an onslope indication they all place you in the touchdown zone.

[training wheels]

My time lecturing in the exams was past when they moved to the 727 as the example aircraft.

What aircraft did CASA use for the Performance and Loading exam before the 727? .. Just curious.

[Tinstaafl]

'Seagull' something or other, I think it was. A fake aircraft like the Echo Mk IV use for CPL.

[john_tullamarine]

What aircraft did CASA use for the Performance ..

I can vaguely picture the Seagull manual in the mind's eye. This, as I recall, came in sometime after I withdrew from active pilot training work. Can't recall at all what Type it was based on, though.

Talking back in the 70s/early 80s, there was NO ATPL performance .. which always surprised me somewhat.

ATPL/SCPL exams included Flight Planning (which was an interesting subject) but no specific performance or weight control work.

As an aside, given that most folk have never heard of SCPL ... in the earlier days of the two airline policy, some shonky practices arose to make it harder for Oz pilots to head off O/S. One of these was the Senior Commercial Pilot Licence (SCPL) which gave similar priviliges to the ATPL but applied to non-airline heavy aircraft operations. Another was the 2nd Class ATPL for F/Os .. needless to say, both were local Oz animals and totally not understood O/S. Even during the 89 nonsense, F/Os who went O/S initially had trouble with their 2nd Class ATPLs.

Given the comparatively simplistic required CPL level of understanding, the end result was that folk moved onto heavy aircraft near totally reliant on operator endorsement courses to make up the shortfall. QF (Wal S et al), AN (John W et al) and TN (Peter T et al) ops engineering ran reasonably detailed training modules .. and the training notes were pretty good/detailed. Wal's pilot notes (Aerodynamics and Performance of the Jet Transport - QF Aero Eng Report 3001) are still sought after by the flying fraternity as a basic engineering text suitable for pilot study.

For the minor heavy operators ... John H looked after IPEC's Argosy/DC9 training and ops engineering ... can't speak to EW in any detail but, on the basis of how they approached their line operations engineering work, I suspect they were not in the same playing field as the other airline operators. Initially, Newton H provided reasonable external consultancy support and, subsequently, Bob P moved into the role after he did his Master's at Sydney. Ron S and Jim D (ex-DCA performance engineer-pilots) may have done some work as well but I think AN had taken over the ops eng support by the time they would have been in a position to have done much for EW.

Getting back to the original question, there are two reasonable considerations -

(a) wet/contaminated runways associated with wx causing Cat 1 - covered by other factors so probably not pertinent

(b) misjudged flare/float/touchdown causing a longer than presumed landing roll. Given the quite reasonable minima for Cat 1, this really is a furphy.

Probably a case that one of the CASA (or precedent organisation) examiners just thought it was a good idea ? The regulator has always been a good source of "good" ideas rather than rigorous deduction.

PFM ?

The only PFM activities on the 727 were with regard to generator parallelling ... and, in any case, who needs a PFM box if you have a real live F/E ? ...

... now the A320 .. that's in a different paddock altogether ...