Author Topic: Improvised Airstrips
Sirkitbreaker
Just another number

Member # 42192
posted 03 December 2001 20:25                

I am doing some research into improvised airstrips pretty similar to those you find in Africa and the Carribbean. Does anybody know of a reference publication or a useful internet source detailing things like runway inspection methods, lightish types for use on such airstrips and anecdotal reports? Pictures especially useful.
I have looked at the Mission Aviation Fellowship site, this is exactly the kind of environment I am thinking of although the site lists few details of runways.

Many thanks
SMK

PS am not planning on going into the drug or gun running business...honest!

null


From: Planet Zarg | Registered: Sep 2001  | 

Tinstaafl
Just another number

Member # 2389
posted 03 December 2001 21:26                

Australia's CASA has a Civil Aviation Advisory Publicaton (CAAP) dealing with Aircraft Landing Areas (ALA)

In Oz anyone can designate an area for the use of a/c (subject to the usual council bureaucrats, if applicable). An ALA is such a strip ie not licenced or subject to any particular oversight by any regulatory authority.

The relevent CAAP gives guidance & recommendations concerning suitable criteria.

Don't have the specific CAAP number but CASA probably has it on their website

www.casa.gov.au


From: UK | Registered: Dec 98  | 

Dave Incognito
Just another number

Member # 18055
posted 03 December 2001 23:38                

CAAP 92-1(1) is the one Tinstaafl is referring to. It covers information regarding ALA dimensions and lighting etc.

Not sure if you can download it off the web site but definitely worth a try.

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Flying is easy - just throw yourself at the ground and miss.


From: A one horse town called Sydney | Registered: Jul 2000  | 

topunicyclist
Just another number

Member # 7326
posted 04 December 2001 10:30                

I assisted with clearing airstrips for MAF in Tanzania several years ago.

Basically the target was 1000 metres long, reasonably flat, 20 metres wide and a further 10 metres or so either side clear of bushes & trees suitable for the wings of an aircraft (e.g. a high wing Cessna) to pass over.

Not really an answer to your question, but there you go.....!

[ 04 December 2001: Message edited by: topunicyclist ]


From: Chichester, West Sussex, UK | Registered: Sep 1999  | 

Tinstaafl
Just another number

Member # 2389
posted 04 December 2001 17:57                

In Dept Civil Aviation/Dept. of Aviation days, their recommended method to test the surface for adequate smoothness was to drive a heavily sprung laden vehicle along the strip at 50mph.

Softness was determined by how deep the tyre tracks were.

I don't think this is included in the CAAP.


From: UK | Registered: Dec 98  | 

OzExpat

PPRuNeaholic


Member # 16428
posted 05 December 2001 10:54                

Tinny... I had an idea that the speed was 30 MPH (ie 50 KMH), but I could be wrong.

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Dispela olgeta samting i pekpek bilong bulmakau!


From: Port Moresby, NCD, PNG | Registered: Jun 2000  |

Tinstaafl
Just another number

Member # 2389
posted 05 December 2001 12:44                

Oh. I thought it was 50 mph.

Don't have the source available anymore...


From: UK | Registered: Dec 98  | 

OzExpat

PPRuNeaholic


Member # 16428
posted 06 December 2001 12:00                

Tinny... neither do I...   We're a bloodey sad pair, huh!

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Dispela olgeta samting i pekpek bilong bulmakau!


From: Port Moresby, NCD, PNG | Registered: Jun 2000  | 

Meatbomber
Just another number

Member # 32101
posted 07 December 2001 13:35                

prolly this helps:

Bush Flying

Cheers
MB


From: Vienna Austria | Registered: Apr 2001  |  IP:

OverRun
Just another number

Member # 21800
posted 18 December 2001 20:33                

Sirkitbreaker, just before the topic closes, let me add my two bobs worth.

Topunicyclist has got the right sort of dimensions. For single engined aircraft under 2000 kg MTOW, runway width 10m, plus 10m strip either side (which is not-too rough ground that the aircraft can run on in an emergency), and 15m either side of fly-over area (rough but clear of trees), for a total cleared width of 60 metres. Length of 1000m is typically fine; some people use a bit less especially with STOL mods. 1200m is often used for twins. That Australian CAAP 92-1(1) is excellent, and is built on decades of bush experience. Let me know if you want a copy.

The three practical things to watch out are:
Rough surface
Soft, wet surface
Takeoff gradient.

Roughness is tested by driving over it in a laden 4wd or utility at 75/80 km/hr (as Tinstaafl suggested). What I do is use the personal car of the local manager/owner - it focuses their mind wonderfully on the strip condition when they have to drive it in their own precious vehicle.

Soft, wet surface is tested by driving over it in a zig-zag pattern at very slow speed and looking for wheelruts more than 25mm which indicate soft areas. Maybe give a couple of spots a dig with a crowbar to check that it is not just a hard dry crust over a soft base (absolutely essential if you're in an old lake bed or there are white salty patches around). If in doubt, borrow a 5 tonne truck and drive the runway using that. If it doesn't get bogged, your 2 tonne aircraft shouldn't either.

The takeoff gradient can occasionally be tricky if the ground is generally sloping. You're looking for maximum 5% clear gradient (which is about 3 degrees). I've been caught just the once where a strip approach looked reasonably clear to the naked eye, but the whole landscape was sloping and the actual takeoff gradient was 11%. If the aircraft had ever got off the ground, it would have hit the rising ground further along. The only way to be sure is to use a small clinometer (costs about US$60), but you can make your own. Got this cute method from a primary school, using a straw, string and protractor. 

Oh, and finally, when the guys who are building the airstrip reckon it's completed to standard, there is usually a few more days work needed to finish it.

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If it's got off the ground at this weight before then it will do it again.


From: Australia | Registered: Oct 2000  |  IP: