Ops beyond the FM ? 10% runway slope

[aseanaero]

An aviation law question , how do you legally handle landing on a 10% slope runway ?

The flight manual for this particular aircraft only goes to 4%. Is it normally handled by a dispensation or approval from the local aviation authority or do you have to go back to the manufacturer for a flight manual supplement ?

Insurance ramifications ? It's an approved airport not an ALA.

The airport in question was previously serviced by Dash 7s and Twin Otters (1,000m elev 5,300ft) but the local DGCA has stopped these aircraft now due to the runway being outside the FM landing performance chart parameters. I was wondering how this is handled in Oz or PNG.

Has anyone run across this before ?


-

[Tinstaafl]

Does the FM prohibit ops at higher slopes? If not then the issue is one of ensuring adequate performance by making sure the outside-the-FM's-limits stuff is acting in your favour. If you take off downhill but base your T/off performance calculations on the FM's lesser slope then you'll at least meet the charted performance. Similarly landing uphill: You'll have a greater upslope than charted but it's beneficial.

[1a sound asleep]

technicality - does the question actually say up hill or down hill?

Landing 10% slope down hill with no performance charts would potentially invalidate insurance, so from a legal aspect I say dont land

[Checkboard]

A 10% slope runway is a one-way strip. ;) There's no problem about landing downhill!

As above - you are not permitted to extrapolate past the parameters of the chart, so you don't. You just work out the landing distance at 4% up-slope and if the strip is long enough for that, you are fine at 10%.

The only other problem is if there is a slope restriction in the manual, in the limitations section (B737 and A320 has one, for instance - not that you would be landing one of those on a 10% slope!).

[Tinstaafl]

It could be used as one way strip. Look at Courchevel: 18.5% and less than 600m at around 6000' elevation.

Oops. Checkers beat me to it.

[ad-astra]

Goroka (5200' elev) in the Highlands of PNG comes to mind with only 2.7% slope it was a one way strip for the F28 whch had a FM supplement from Messrs Fokker ond Co at HUGE expense to the management!

What made it one way was more the length and a small forest on a dirty big hill just outside the uphill boundary fence. We operated on committal heights as well and 'experimented' with F25 landings for a short period of time. But thats another story.

It was fun though.

Chuck will certainly be along soon with info that will be more current and appropriate to your question and percentage of slope.

[Torres]

Goroka (5200' elev). Plus the Post Office tower and a row of pine trees along the boundary - but it didn't stop at least one C206 pilot landing down hill!

aseanaero, you mean strips like this?

http://img.photobucket.com/albums/v315/Woomera/PPRuNe/NiceRunway.jpg

[compressor stall]

The only other problem is if there is a slope restriction in the manual

And Checkboard, this is not necessarily limiting either with appropriate manufacturer support. Not a problem with e.g. Airbus:8, but unlikely to be given by a small GA manufacturer that may not exist anymore.

[T28D]

Checkboard, You are Kidding ??????

A 10% slope runway is a one-way strip. http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif There's no problem about landing downhill!

[chimbu warrior]

It really depends on what performance criteria you are required to meet. Below 5700kg there is no specific requirement for a balanced field; above 5700kg there is. If the proposed operation is <5700kg there may be no problem; if >5700kg potentially lots of problems.

If you take off downhill but base your T/off performance calculations on the FM's lesser slope then you'll at least meet the charted performance.

Actually this cannot be assumed, again dependent on performance requirements. Aseanaero mentions that this strip was originally served by Dash 7 aircraft, if so they would need to prove that they could accelerate to V1 and then stop within the prescribed ASDA. The limiting factor would most likely be braking from V1 within the ASDA limits, a figure that the manufacturer is unlikely to have determined (for a 10% slope) during flight testing. I'm guessing there is no stopway for this strip (or at least no stopway that offers the option of using the aircraft again).

[ControlLock]

If you want to cover yourself legally, then get yourself a CASA or local regulator approved design engineer.

They will take the current aircraft performance data and create new performance charts for the slope and or wind corrections you require. This will then be submitted to regulator and once approved can be inserted into FM for company operations.

In our organisation, we check pilots into every strip greater than 5% as routine.

Above 5700Kg, as stated, you may be prohibited by regulations and or aircraft manufacturer.

[aseanaero]

http://img.photobucket.com/albums/v315/Woomera/PPRuNe/NiceRunway.jpg

I've seen this photo a few times where is it ?

Actually this cannot be assumed, again dependent on performance requirements. Aseanaero mentions that this strip was originally served by Dash 7 aircraft, if so they would need to prove that they could accelerate to V1 and then stop within the prescribed ASDA. The limiting factor would most likely be braking from V1 within the ASDA limits, a figure that the manufacturer is unlikely to have determined (for a 10% slope) during flight testing. I'm guessing there is no stopway for this strip (or at least no stopway that offers the option of using the aircraft again).

I think that ASDA is the issue , the Dash 7 operator has asked me to try and find a solution for them then provide them aircraft if necessary. When I asked some very experienced aviators I have got a range of responses which reflect the responses here on this thread.

The airport has swallowed up a few aircraft but mainly CFIT , there was one incident where a Twin Otter went off the runway.

We've considered using helicopters (KA32 and Mi8, Mi17) up there but the cost is PROHIBITIVE, it needs to be a fixed wing solution but the the payload needs to be 2,000 to 4,000kg. At the moment I'm thinking Carribous but the FM is 4%. As usual they're on a budget and that just makes things more complicated

The Indo DGCA turned a blind eye to the slope / FM issue for years but then stopped it.

Goroka (5200' elev) in the Highlands of PNG comes to mind with only 2.7% slope it was a one way strip for the F28 whch had a FM supplement from Messrs Fokker ond Co at HUGE expense to the management!

I'm thinking an FM supplement (Manufacturer , TC holder now Viking Air or a Design Office) for their existing Dash 7s maybe the solution and a lot cheaper than buying additional aircraft but if the Dash 7 can't do it the Carribou should be able to do it.

p.s. I had one left field idea of using military surplus OV-10 Broncos as fuel tankers (STOL and 2,500kg payload with a 1,000 litre centreline belly tank, 6 hard points and an internal cargo area that can carry 4 x 200 litre drums) but the DGCA can't comprehend restricted category aircraft even though it's accomodated in the Indo CARs (which are similar to FAA)

[aseanaero]

Thanks Yap-Yap

The operator is telling me 1,000m , this shows 810m , I'll quiz them tomorrow , you're right , it's going to be tricky to find any aircraft to fly into this strip with a decent sized payload.

ps. well spotted, you worked out which airport :-) Caravan driver with Susi perhaps ?

[aseanaero]

The chart is pretty old, it may well be a little longer now, Indoavis says 900m, I'm sure nobody really knows

Welcome to Indo ... the operator just came back and told me yes 900 metres not 1,000 as they originally said

[Torres]

I've seen this photo a few times where is it ?

It is an MAF 206 on a mission strip. I had an idea it was south of Kundiawa in Chimbu but that has been disputed with claims it is in West Irian.

[john_tullamarine]

Below 5700kg there is no specific requirement for a balanced field; above 5700kg there is.

Not quite the case.

The only "requirement", per se, is a defacto case where a specific AFM may have presented ONLY BFL data (DC9 comes to mind). Most have data permitting an unbalanced calculation and, near invariably, the best weight comes for an unbalanced calculation departure.

BFL's only desirable characteristic is that it provides the simplest and quickest calculations - but, generally, not the highest MTOW.

Alternatively, please do cite the rule and I shall go quietly, having learnt my something new every day ..


They will take the current aircraft performance data and create new performance charts for the slope and or wind corrections you require.

In a previous life I did this sort of stuff as an ANR 27/40/41 and, subsequently, CAR 22/35/36 chap. Not quite as simple as suggested above for other than simple extensions and may/will require specific flight testing depending on the story. The actual work, however, is pretty straightforward.

[Chimbu chuckles]

Dunno why you'd think I would be along with useful info - in my day you started off with a conservative guess - added 1 more bag of coffee (40-50kg) on each subsequent trip until you gave your self a fright and the next time lifted one less bag of coffee....worked good.

I do remember there was a section in the Talair Islander ops manual with MTOWs for a bunch of steep strips - if memory serves some had MTOWs < BEW - which indicated immediately that further reading was merely blowing sunshine up the ar$e of whomever wasted their time writing said drivel.

Beyond such high brow considerations we just figured steep was good...REALLY steep was Gooder.

[StudentPilot479]

Definitely not the legal solution, but I'd be curious to know how heavy a Dash-7 could be on take off to have an engine failure at V1 (I suppose a lower speed would actually need to be used) and, using the slope and power from three good engines, still get airborne (which I am assuming is possible). Also how well it would fly afterwards at that weight (ie can it make a normal flight to it's base or would it require taking an alternate, lower, route home?). If they are hauling fuel and returning empty or with empty drums, I would be quite surprised if they could not safely depart (but yes, safe =/= legal).

If it can get airborne on three and fly home, it would be far safer than a Caravan or other single engine plane losing an engine in the middle of the take off roll and crashing/going off the end. But I doubt they could ever convince a bureaucrat to accept that it improves or maintains the current level of safety despite being outside the normal rules.

Sadly the easiest solution would probably be to pay off the DGCA officials...

[Flingwing47]

Worked in PNG and West Irian for a few years in the '70s. Many strips had V1 at brakes release! Miss all that fun:(

[poteroo]

My recollection of steep strips was that you could accelerate/stop a twin on many 800-900 metre strips if you used only a max of 4% as per current charts. However, if you 'extrapolated' a little and looked at what distance you needed with a 10-15% strip......... you may as well have called in a Chinook and had it airlifted home!

As Chuck says - if you only had a single fan - then the steeper the better! Ompkali and Efogi come to mind as one locale where the acceleration was mighty gooder!

happy days,