Take off weight limitations at Pico (LPPI)

[flyinGuppy]

Hi! Before any of you can answer my question you have to know what I'm talking about so I leave here a link to the Aerodrome obstacle chart of Pico Airport:

http://www.azoresspotting.net/privado/medeiros/PB010058.JPG

Knowing the facts I would like to know how much weight could an A320 carry out of both runways in a standard ISA day with no wind.

Also I would like to know how those weights would be if you had the runway extended 400 meters at the beginning of rwy 09. Because that way you would have a bigger runway, but from 27 the obstacles could become more important and restrict the take off weight in such a way that the runway extension would be of no value if using 27

I understand that answering these questions probably requires some calculations and waste of time, but I would really appreciate if some one goes trough the trouble to get me these numbers.

Tank you for the attention

Rui Medeiros

P.S. if you can get these numberes for another kind of aircraft I would appreciate it also

[flyinGuppy]

Could some one get me the charts where I could find the info I'm looking for insted?

Tanks again,
Rui Medeiros

[enicalyth]

The best people to ask are at Airbus but unless you are on their list they will not divulge privileged information. Next best is to approach your own CAA because they will licence the aerodrome for the type of operations permissible. At the very least begin with ICAO Annexe 14 Vol 1 especially Table 4-2 and thereabouts.

Your AGA of 14 FEV 2005 is very good but does not give in detail how TODA, TORA, ASDA and LDA arrive at the posted values nor what the pavement classification number is.

I have assumed 1405 metres useable constructed length of 30 metres width at present. It needs an upgrade.

To licence A320 ops your CAA will probably be looking for 45 metres width with graded areas beyond and on each side AND two 300 metre Runway End Safety Areas. They may accept 240 metres each end. I know that you will find existing airports with 90 metres or even 60 metres RESAs. That was then, this is now and some authorities can be very hard to convince otherwise.

275 (or 215) metres of one of these will be available for take-off giving an ASDA of 1680 (or 1620) metres. This arrangement meets in outline at least the needs of a category 4D aerodrome. So going for a worst scenario of 1610 metres and near flat slope let see what can be done.

An A319-100 with V2527M-A5 engines, SepcarbIII brakes and BSCU to Std 9.X will in zero wind at 31 deg C and 2000ft pressure altitude be accelerate-stop limited to 70 tonnes. Unlimited it would be 75.5 tonnes. Maximum landing weight is 62.5 tonnes for an LDA of 1610 metres.

Looking at the AGA and obstacles 1-9, I don really have the full picture of what happens OEI but at least to start a discussion, we’ll investigate LPPI-KBOS. Payload of 12150kg. Headwind 29 kts. FL350/390. M0.78 cruise. ISA +10 en-route and 31 deg C, 2000ft pressure altitude, zero wind at Pico. l revise my take-off weight limit therefore to 66 tonnes.

Needs more work I know.

[flyinGuppy]

Tank you for the answer, by now I wasn't expecting to get any.

I will try to give you the other numbers you need.

The pavement classification number is now 80 F/B/W/T, about the runway lengths, between thresholds there are 1580 meters then we have 225 meters more from rwy 09 from which 90 are declared RESA, them 60 are clearway between the RESA and the beginning of TORA which starts 75 meters before threshold, and only these 75 meters are also PCN 80 before threshold. At rwy 27 we have 150 meters before threshold from which 90 are RESA and 90 are also taken in account for TORA as they are also PCN 80.

So Landing on 09 you have 1580 LDA which is the pavement between thresholds, landing on 27 you have 1655 LDA which is the 1580 plus the 75 meters after the 09 threshold

Taking off from 09 you have 1655 TORA using the same surfaces as for landing in 27 a departing from 27 you have 1745 which are those 1655 plus the 90 meters before 27 threshold, those numbers are the same for ASDA

The runway is 45 meters wide, with 7,5 meters shoulders and the strip is 150 meters wide.

About the RESA required being 240 meters I didn't know that was the rule now, but the runway was recently certificated (begining of the year) with 90 meters RESA which I thought was the minimum required.

I can tell you also that TAP operate at LPPI with the A320 in the route LPPT-LPPI-LPLA-LPPT or LIS-PIX-TER-LIS, and I will try to know how much weight can they carrie from here.

The information I was looking for is if the obstacles we have as depicted in the chart are responsible for any degradation in the take off weight allowed, or if it happens just because of the short runway, and if those obstacles would cause any take off restrictions if you had a runway just long enough as to not be a restriction and the same obstacles ahead.

Once again tanks for your reply, and I hope I managed to explain how the runway is like here.

Best regards
Rui Medeiros

[enicalyth]

I am on holiday at the moment but will try to sit down and work this out.

There are no "rules" by the way, only strong recommendations, when it comes to certificating airfields.

[flyinGuppy]

Hi Again!

I managed to find this picture where you can see how the declared distances are obtain: http://www.azoresspotting.net/privado/medeiros/PB160059.JPG

Also I talked to a guy who works at Pico operations, and he said that the last flight from TAP gave him a take off weight restricion of 64.6 tons. This was an A319, he also said that he tought the restrictions are only runway drived.

I'm sorry to disturb your vacations, I hope you enjoy them, and tanks again!

best regards
Rui Medeiros

[enicalyth]

Thanks for that last sheet. I had a little difficult putting the figures together. One has to be very careful with terminology. Stopway, Clearway, RESA. My original estimate of 66 tonnes may well be too high now that I see a little more clearly what the situation is.

A useful download from Airbus is "Getting to Grips with Performance". Don't forget the OEI manoeuvre!

Best Rgds,

"E"