"Short Field" 3000' [Archive]

Aussie Andy

9th Dec 2003, 20:34

Things are different in the US: was bemused to read an article on iPlot entitled Short Field Challenges (http://www.ipilot.com/learn/article.aspx?ArticleID=902&ns=fi) which starts our as follows:We've had a number of accidents at a nearby airport with a "short" runway. The reason I say it is "short" is because at 3000 feet, it isn't a mile long - judging by the number of planes that have gone off the end of the runway and into the creek, some pilots need it to be. If you are the type of pilot that can learn from the mistakes of others, read on...Not a bad little article in its way: but shocked that anyone could consider 3000' (i.e. 914m) short! :O

My rule of thumb, given that I learned at Wycombe where the main RWY is 735m long, is that I only give much of a second thought if the runway I plan to use is much shorter than that! In fact I find I am paranoid about "short" runways, i.e. less than about 600m or 550m say, and do all the calcs multiple times, and generally chicken out to the point where I think I should get some training for "short" fields in a suitable aircraft one day!

What do others think of as "short"?

Cheers,

Andy :ok:

Keef

9th Dec 2003, 20:56

Depends very much on what I'm flying. The Arrow is fine into 800m, but much less than that and I start to get out the charts and decide on weight etc.

There's a little GA field near Sheffield called Netherthorpe, and I wouldn't dare to try to get the Arrow in there. If I got in, I don't know if I'd get out again!

We used to have a former Arrow serviced at Thurrock: it was a case of one-up, low fuel, push it back till the tail was over the hedge, full throttle against the brakes, then blat off at full chat and pop two stages of flap at 55 knots. Did that a few times, and decided there must be an easier way...

3000 feet is short by US standards - but where was this one? Hot and/or high?

Field In Sight

9th Dec 2003, 20:58

I instruct at a grass strip in the North west and the runways are pretty small i.e. 400ish to 600ish metres.

Even the large runways are pretty scary on a warm/calm/fatter passenger type of day.
Landing is not really a problem though if the actual POH speeds are used.

It really does make you concentrate on the correct climb speeds I can tell you.

FIS.

BTW I've trained in he US and really miss those 10,000 ft runways.

Fly Stimulator

9th Dec 2003, 21:00

Calling 900m short does seem somewhat conservative.

My home runway is just under 800m and that, although not exactly huge, feels perfectly adequate.

The shortest places I've taken the SR20 into are Old Buckenham and Bourn, both about 640m. No problems in either case, though I was paying particularly close attention to approach speeds. I think I'd use 550m as my personal minimum in that aircraft at the moment, assuming clear approaches and less than full load.

When I'm flying the CT I'm quite happy down to 250m and start to think seriously after that.

I've flown one or two slightly tired training aircraft which I imagine would quite easily get into places which they'd subsequently never get out of, so there is that side of the coin to consider too.

I think Cub drivers are probably the ones best able to get onto and off postage stamps though.

Genghis the Engineer

9th Dec 2003, 21:15

All things are relative.

Let's say we've got an airfield at 8,000 ft and ISA+20 (far from impossible in parts of the US). Applying all the usual safety factors you need a standardised take-off distance not more than 890ft (271m) on a 3,000 ft runway. That's marginal for a lot of GA types - without a headwind and at MTOW it would exclude a PA28 or C172.

G

IO540

9th Dec 2003, 21:21

This is a general Q re short field procedures.

I was never trained in anything like that, nor does my POH mention these. You keep all wheels on the ground until Vr and then decisively pull it off. I've never had any reason to do otherwise since I fly a not exactly cheap retractable and the very short fields (say <600m) are often also very rough and at this time of the year very muddy.

The general procedure I've heard mentioned is that you start with full flap, pull pitch all the way back, lift the nosewheel as soon as it lifts and hold it there, then lift the main wheels off and stay in the ground effect; when at Vr retract flaps to the takeoff setting (say 10deg) and rotate up. But this comes from someone who flies very old planes into farm strips of <400m.

I wonder if there are some planes on which there isn't enough aileron authority to hold the plane level (against the engine torque) at the point when all 3 wheels are off the ground - for Vr of say 75kt this could be as low as 50kt.

FlyingForFun

9th Dec 2003, 21:31

I wonder if there are some planes on which there isn't enough aileron authority to hold the plane level (against the engine torque) at the point when all 3 wheels are off the groundI would be very surprised. For one thing, characteristics like this would make a late go-around nearly impossible. I'm sure Genghis will know for sure, but I suspect there is some regulation or other which requires the aircraft to be controllable at full power at any speed at which it's capable of flying.

(And anyway, in my limited experience, rudder authority against slipstream effect and p-factor is more likely to be limiting than aileron authority against torque?)

I'm not registered on that website, so I can't read the full article, but I'd guess from the responses on this thread that it describes the standard short-field take-off technique which I was taught for my PPL, of holding the yoke back on take-off, and lowering the nose once the wheels are off the ground in order to accelerate in ground effect? Very similar to the soft-field take-off (the start of the take-off roll is different) which I was also taught for PPL? The same short/soft field techniques that I practiced again for my CPL? Never had to do a short-field take-off for real, but I promise you that the soft-field take-off works quite well when trying to get off the muddy ground at White Waltham towards the end of the winter!

FFF
-----------

IO540

9th Dec 2003, 21:38

FFF

requires the aircraft to be controllable at full power at any speed at which it's capable of flying

flying yes, but flying in ground effect? There is a big difference in IAS between the two.

For mine the stall speed in landing config is 59kt. One could get fully airborne in ground effect at 40-50kt.

Genghis the Engineer

9th Dec 2003, 21:42

I'm sure Genghis will know for sure, but I suspect there is some regulation or other which requires the aircraft to be controllable at full power at any speed at which it's capable of flying.

Damnit, people are taking me seriously again, I hate that.

Yes, there is. They are all much of a muchness, but taking FAR-23 which is the most common safety standard for light aircraft...

Sec. 23.143 General.

(a) The airplane must be safely controllable and maneuverable during all
flight phases including--
(1) Takeoff;
(2) Climb;
(3) Level flight;
(4) Descent;
(5) Go-around; and
(6) Landing (power on and power off) with the wing flaps extended and
retracted.
(b) It must be possible to make a smooth transition from one flight
condition to another (including turns and slips) without danger of exceeding
the limit load factor, under any probable operating condition (including, for
multiengine airplanes, those conditions normally encountered in the sudden
failure of any engine).

There's a lot of fine detail in the next few pages but that seems to pretty much cover everything. (There's also a couple of paragraphs near the start of the book which say that all this must be met at any permitted CG, weight and power setting).

G

FlyingForFun

9th Dec 2003, 21:43

In that case, IO540, 40-50kt would be the speed that you'd be flying at, in ground effect, just before the wheels touched in a full-stall landing. Which would be the same speed at which you'd want to be able to control the aircraft, with full power, when Mrs Jones' dog gets free of its lead and dashes onto the runway just before your wheels touch. No?

FFF
---------------

Say again s l o w l y

9th Dec 2003, 21:53

For most types on a muddy field, you won't have too many problems with elevator authority. It isn't an issue due to the propwash.
Before we had a tarmac strip laid, a 'soft' field take off was the order of the day. We never used to retract flaps to the T\O setting as that was where we had them from the very beginning.
Full rearward elevator deflection. Full power, get the a/c into a 'wheelie', keep it straight, allow the a/c to 'pop up', hold it in ground effect until at a safe speed, then rotate into the climb as normal.

The technique works very well in C150/2's, C172's, HR200's and PA28's, but I wouldn't recommend anyone in a retractable machine to use it if it is very boggy. As I wouldn't be happy in a retractable in those conditions anyway.

PPPPP

9th Dec 2003, 22:13

Landing is not really a problem though if the actual POH speeds are used

Just got back from an IMC lesson at Barton in a C172 landing on 09L ( 518m) 2 up with 100 litres of fuel still on board. 60 knots and 40 deg flaps, surface wind 130/less than 5. We would have stopped at the halfway mark if I'd braked instead of rolling on to vacate right to the apron. No special skill on my part involved, just POH speeds. So the answer to the original question is: after experience at Barton 400m or less would seem short.

QNH 1013

9th Dec 2003, 22:52

Keef,
Arrows and Twins do go in and out of Netherthorpe, (having done their sums first of course), but the airfield is now PPR by telephone, probably because they were getting fed up of mending the hedges. R/W 24 (470m) and R/W18 (380m) have upslopes which need to be factored. I understand that 18/36 is the shortest licenced runway in the country. I certainly don't know of anyway shorter that is licenced.
Plenty of pilots do their first solos at Netherthorpe, there are two schools on the site, hence the need for the runways to be licenced.

big.al

9th Dec 2003, 23:45

I've done a bit of flying from Netherthorpe, and yes it is short. In fact the C150s struggle to get out with two-up and a decent fuel load if 18/36 is in use, unless there is a very decent headwind straight down the runway.

Flying out of 18 once with an instructor, he told me to take off without the usual 10 degrees of flap in the 150. We only just cleared the hedge at the end by about 6 feet, which was the point I think he was trying to make.... don't forget the short field technique when flying from there! Many people (and planes) have been through the hedge - too many in fact, hence the reason that the PPR by 'phone is being more strictly enforced. Great little airfield though.

camaro

10th Dec 2003, 00:13

Yes, Netherthorpe is the shortest licensed airfield in the UK.
As already touched on, it isn't really a problem provided you do your weight/balance sums properly. We currently have an Apache, a couple of Commanches and a Bonanza on the field.

Anyone interested in brushing up on short/rough field techniques would be made very welcome at Sheffield Aero Club or Phoenix Flying School.

If you plan to visit EGNF please phone for PPR before hand. Oh yeah, there's no landing fee for PFA types or if you purchase fuel. Fantastic grub in the SAC clubhouse too!

Algirdas

10th Dec 2003, 00:36

For a short runway, try Shottewell's 06 - It's published in Lockyear's as being 09/27 at 853M, but it sure ain't that now.
The AFE book has it right, but I don't remember the exact length - I flew in expecting the 853 M, noticed it seemed a bit shorter than that from the air, and found it was a lot shorter than that on my way down - about 400M, AND it's downhill.
Piccy of Shotteswell (http://www.multimap.com/map/photo.cgi?client=public&x=442460&y=244960&scale=25000&width=700&height=410&multimap.x=428&multimap.y=208)
Much easier to use 15/33 at 965M !!:ooh:

WorkingHard

10th Dec 2003, 00:41

300m strip in 172 close to Thatcham. is OK in and out because of gradient. C182 is resident

Algirdas

10th Dec 2003, 00:41

IO540

10th Dec 2003, 01:48

Genghis the Engineer

I have read somewhere that only planes certified after about 1980 (very few of those flying today, though mine is) need to meet FAR-23. FAR-23 contains some specific spin recovery requirements but is quite recent.

Genghis the Engineer

10th Dec 2003, 03:13

FARs, JARs, BCARs, etc. keep on changing - but they've been around and mandatory since long before 1980.

A quick check here (http://www2.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/MainFrame?OpenFrameSet) shows that the C140 wasn't certified to FAR-23 but all models of C150 were. That dates implementation to somewhere between 1945 and 1957, and should certainly include pretty much anything most of us are flying today.

That would match the fact that my Y2000 copy of FAR-23 is at issue 54, about one amendment per year would be in the right order.

G

Dude~

10th Dec 2003, 20:55

Short field... hmmm.
It all depends on pilot ability and confidence.
Many people consider a runway that is twice the POH landing run to be short, ie 300m or so for a typical cessna (don't quote me), but that soon reduces with experience. Half the problem comes from too little practise and accuracy in approaches.
For me, changing to Elstree at 200 hours experience seemed short, but a few landings in a PA32 Cherokee Six with 5 pax and lots of fuel, downhill, turning off at taxiway Alpha about 450m from the threshold soon changed my perception of short.
To think I was ever worried about Popham in a C172..!
Some faily expensive / fast stuff is based at Elstree. Watching a turbine Piper Mailibu (Mirage?) or TBM 700 land is impressive, as they tend to aim very close to the numbers in order to avoid wasting runway, unlike the spam cans who float over the numbers at 60 ft and 75 kts...!