Flight Planning Weights - missed approach ATPF

[aseanaero]

We are about to commence operations at a hot and high airfield with a Bae ATPF when the subject of what is the correct weight to use for landing weight came up.

The route analysis by Bae Systems and the FM show a permissable landing weight at this airport of 21,247kgs (down from MLW 23,133kgs) however the captain wants to use the TOW of 20,248kgs at the destination airport as his max landing weight as he is concerned about missed approach or aborted landing performance.

I would have thought missed approach or aborted landing is ok at a landing weight limit of 21,247kg as the aircraft is either still flying or is still doing 80kts on the runway so the higher weight can apply as long as the climb gradients are still good to avoid terrain on climb.

The freighter will be coming out of the strip at about 17,000kgs , virtually no payload coming back to base.

This is a safety versus revenue argument obviously and while we don't want to put crews in danger and we'll accept the arguement if it can be shown that for whatever reason the aircraft won't perform within safety margins at 21,247kgs we don't want to lose 20% of revenue paying payload if it's within the capability of the aircraft (even allowing an additional margin for aircraft perfromance degradation due to age).

Your thoughts and opinions please.

[Capn Bloggs]

so the higher weight can apply as long as the climb gradients are still good to avoid terrain on climb.
That will be the issue. While the AFM may say "OK" at the airfield elevation, the final altitude of the Missed Approach will be the issue. If the final terrain clearance altitude/MSA is very high, the weight may have to be lowered to ensure the aircraft can get there in the event of an IMC missed approach. The weight to achieve 2.5% (PANS OPS MApp gradient) at 2000ft AMSL will be higher than that to achieve 2.5% at 5000ft AMSL.

[mutt]

The first question is..... what regulations are you operating under?

What is limiting the takeoff weight to 20,248 kgs? If it is an obstacle in the takeoff path, then you dont have to use this weight, nor if its field limited!

What you need to check is the landing field, the approach climb and the landing climb charts.

All presuming that for Indonesia, the regs are closer to FAA than JAA. :)

Mutt

[411A]

What you need to check is the landing field, the approach climb and the landing climb charts.

We do this with some airfields in Africa with L10 aircraft...using FAA data, only.
None of this JAA nonsense:}

[BOAC]

asea - when posing questions like this it helps if you indicate your involvement so you don't get silly replies, and the replies can be tailored to your specific needs.

Your profile indicates a 'metal trader' with only light twin/single experience. Should you update it? Also as Mutt says, which regs are you looking at?

[aseanaero]

Initial calcs were done by Bae using JAR requirements and reserves even though Indonesia uses a system based on FAA with some local changes.

Bae confirmed via email last night that their calcs already took into account climb gradients for a missed approach.

My involvement is helping out a friend of mine who owns the company (non-aviation guy who inherited it) and is getting conflicting views from his own pilots.

I've recommended to the company that they get a review from Bae Flight Ops Support which will carry more weight with the company pilots and local aviation authority than a 'metal trader' with a basic CPL :) (most days I really enjoy running my business by the way)

Thanks for your comments everyone.


.

[FE Hoppy]

The route analysis by Bae Systems and the FM show a permissable landing weight at this airport of 21,247kgs

Job done as far as I can see. If BAE have done a route analysis and calculated a max landing weight then for the regulations used in the calculation it is the answer. If the actual regulations are more restrictive then using the max TOW based on the non applicable regs as max landing weight is not the answer.

[aseanaero]

This particular airport has had a few CFIT accidents in the last few years (involving aircraft that were suspected to be overweight) so it isn't an easy airport to get in and out of.

I suggested to the owner that the first few weeks of operations that they go in light and let the pilots get comfortable before pushing the performance limits and he's agreed to that.

[john_tullamarine]

I suggested to the owner

A near total waste of time but fine for the pilots.

Either the operator goes in and does the ops eng studies properly ... or it is just a matter of time ...

I presume we are talking Indonesia (love the place). Based on operations and engineering/maintenance audits I've done in country in years gone past it is no different to anyplace else .. the pilots can fly OK but pilots are not well placed to eyeball escape routes in anger.

If we are talking a lower level operator, then there are things in your posts which raise my eyebrows.

I recall one case where a similar class aircraft was operating to some quite questionable RTOW charts (although that was not evident on first glance). Sitting in whichever airport lounge, waiting for the flight which didn't turn up yesterday, I idly did some back of a fag packet sums from the flight manual and twigged to the underlying problem which was one of simple technical error and lack of knowledge. A five minute brief on the phone back to the MD of the company who had commissioned us to do the audit and my brief was changed very quickly from "check for problems" to "fix the problem".

Who knows,depending on which operators they flew for at the time, some of your pilots may recall Pak John from those earlier days.

[aseanaero]

Hi John,

Yep it's Indo , about going in light for start up we have to give them a win , it's an Asian loss of face thing ...

[john_tullamarine]

I presume that you read the local signs OK ..

You might like to run an email discussion on the side .. I am quite happy to provide some comments.

[mutt]

it's an Asian loss of face thing ... Sorry but i disagree... The higher weight is either right or wrong! Therefore you have to have it analyzed and prove to the crew that its right, this idea of lets try the lower weight and when happy, increase it, is crap! That just means that you arent 100% satisfied of your/BAe calculations!
We operate from parts of Indonesia, the crews hate it! (Apart from CGK), the runway limited takeoff weight is really RUNWAY LIMITED! But if we dont use the Boeing published weights, the flight will require a fuel stop, the costs and times involved in doing so will make the whole operation unviable! So we educate the crews and explain exactly what is limiting the takeoff weight, these flights have now operated for the last 5 Hajj seasons successfully and safely.

Mutt