Improvised Airstrips

[Sirkitbreaker]

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 (http://null)

[Tinstaafl]

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 (http://www.casa.gov.au)

[Dave Incognito]

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.

[topunicyclist]

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 ]

[OzExpat]

There's a thread, on the Questions forum I think it is ... topic is something like "most interesting approach". I probably should know it better, being as how I contributed to it, but there ya go.

It might help you a bit.

[Tinstaafl]

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.

[OzExpat]

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

[Tinstaafl]

Oh. I thought it was 50 mph.

Don't have the source available anymore...

[OzExpat]

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

[Tinstaafl]

Not anymore I'm not. I'm a happy bunny courtesy of a certain person... ;)

[OzExpat]

And so ya oughta be mate! :) I hear that the Shetlands wx is gunna be "bare-able" for a while... :D

[Meatbomber]

prolly this helps:

Bush Flying (http://www.fepco.com/BF_Table_of_Contents.html)

Cheers
MB

[OzExpat]

Pax... well the lady in question (not to be confused with a "questionable lady" :D ) is still anonymous coz nobody has mentioned her either by name, reputation or description :rolleyes: But I'm led to believe that she's quite broadminded ... but, then, I'm easily led... :D

[OzExpat]

Pub??? Did someone just use me all-time fave 3-letter word? :) :)

<checks thread again...>

Ahhh it was you, pax! Doncha know that it's MOST unladylike to stomp and pout? :D

[Sirkitbreaker]

Guys,
Thanks a million for the useful leads and pictures on web sites, it has been very useful

TA
SKB

[OverRun]

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. http://www.zip.com.au/~elanora/tclinom.html

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. :D