Short runway?

[B737900er]

Hello,

A simple question : What would you consider a short runway?

Assuming flying B737, would you say a runway less than 2300M (7500ft) is classed as a short runway?

Opinions would be appreciated.

Thanks.

[c100driver]

My airline defines a short airport as 1700 meters or less and our shortest was 1305 meters in the B737, but this one has now been lengthened to 1500 meters.

Special crew training required for airfields less than 1700. Normal ops for any crew above 1700 meters.

[JammedStab]

I would think that in a 737-900 like most reasonably large aircraft, it might depend on your weight, the wind conditions, runway conditions, elevation, slope and perhaps a few other things. What is reasonable one day might be short the next.

We used to land on 5000 foot gravel runways in the -200 and Alaska Airlines apparently did 3,900 feet in Dutch Harbour. That is short.

[sevenstrokeroll]

I routinely flew into Chicago Midway in a 737 and landing it didn't seem too short...now takeoff, it seemed short!!!!

I don't have my jepps handy, but the following airports demanded a little extra attention

KDCA
KLGA
KDMW
KSNA

generally, I would say less than 7000' is demanding of extra attention, but short is less than 6000'

[westhawk]

Another way to look at it is that any runway where the perf data says you'll need more than 60% of it is "short". Works at any WAT too!


One charter company I worked for had authority (EOD operator) to operate to airports where up to 80% of the ALD could be planned to be required. Hence, these runways were considered "short". Certain operational restrictions applied of course.

With all the mountain resort destinations we flew to in the small jet charter biz, I also came to consider any runway with an elevation greater than it's ALD to be one worthy of extra respect, particularly in winter weather. Common destinations like Telluride, Co (9,038 elevation and 6800' or so ALD) stand out as an example.

One company that merged with ours used an arbitrary 5,000' to define a runway as being "short". I always considered that viewpoint to be rather "short-sighted". The pilots from that outfit adjusted to and came to appreciate our approach to the matter of defining a short runway.

I understand that airlines operating larger airplanes may have a different take on it, but I thought the above to be worthy of consideration.

Best,

westhawk

[Capt Chambo]

Personal yardstick is 6000' or 1800m. (-800 & -900). Purely based on previous experience, my company has no definition of "short".

[B737900er]

Thanks for the answers!

I understand that landing distance changes all the time as another poster has mentioned, but I was looking at a general number.

Our company and proberly most companies use Autobrake 2 for most landings, but lets say you was going to an airport with 2000M runway, if you had a general ball park figure you would say "ok that's a bit short lets go Autobrake 3" for example then check the landing distance table.

My company doesn't define what a short runway is. A TRE told me 2300M he would consider a short runway.

[de facto]

If the QRH landing distance requires you to use AB3 and touch on the 1000ft -1500ft' marker then I consider it short.
That would equal to 1800-1900 Meters at max landing weight.

[B737900er]

So you could say 1800-2000M you would consider a short runway then.

Reason I ask is, that you could be flying along and you needed to divert into an airport. Lets say your unfamiliar with the area, so choosing a suitable airport could be difficult. If for example, I saw a runway at 1900M and its suitable for passengers and operations but there is another airport 30mins down the road at 2400M but I needed to land now due to whatever reason it may be.

If I had a rough ball park figure in my head, I could say no that airport is not suitable with such a short runway.

I wouldn't choose to land at Cranfield (EGTC) in any occasion unless I was falling out of the sky due to the runway being rather short.

[autoflight]

A320 I considered 1800 m or less to be short. In this case I used autobrake medium and went for manual braking when safe roll-out was assured.

[de facto]

It is obviously subjective and depends on the weather and fatigue but if you daily look at your ACTUAL landing distance/touch point versus the QRH landing distance, you will realize that when the runway ends rather than the usual planned high speed exit,you will feel confident or not to achieve it safely with,if needed,an extra bonus of higher AB setting such as MAX or manual braking.

[BOAC]

B737900er - I don't know what the latest FMC update does, but Boeing always used to recognise '6000ft' as a 'useable airport in terms of what is displayed on the map page (737). I think even for the 900, that is fine - as de f says, your actual normal landing distance is small. Any deviation from 'normal' in terms of a/c or weather, then into the QRP. There could well be occasions when 8000ft is not enough!

[B737900er]

BOAC-Thank you!

I remember reading or even hearing that the MAP displays suitable airports but I couldn't remember where I got that information.

[PJ2]

BOAC;
Re, "There could well be occasions when 8000ft is not enough! "

Very true...those of us who operate (or did operate!) in Canadian winter conditions know this well. That said, in my experience 6000' is viewed as "short".

Runway distance remaining is always a concern in such operations, especially when contaminated. The CRFI (Canadian Runway Friction Index) is a very helpful tool in the decision-making process.

FOQA Programs can also help. FOQA can go well beyond just recording aircraft parameters and event thresholds.

Using the longitudinal accelerometer parameter, the available runway length data and some mathematics to calculate the runway remaining from the t/d point, a "potential overrun" FOQA event can be created by making an assumption of deceleration rates. While a bit subjective, "heavy braking" is generally around 0.4g to 0.5g longitudinal acceleration. "Normal" braking is around 0.2 to 0.3g.

If normal braking rates are assumed for the purposes of the event, then the runway remaining at that deceleration rate can be calculated. It is an easy matter to then see how that distance compares to the distance remaining from the touchdown point. If the distance is less, theoretically, there is "runway remaining". If the distance is greater, then a possible overrun event is created. That data, always de-identified, is trend-monitored and fed-back to Ops and Training as well as the pilots.

In terms of the calculation, runway surface condition don't matter - what matters is the achieved deceleration rate.

The focus is clearly on shorter runways and airports where runway contamination occurs. But landing long or hot just because the runway distance can handle it can form habits that don't serve one well when one has to "get it right" on a short runway.

NOTE:
For those who may not know about or understand FOQA/FDM programs, a caveat and warning; This will not prevent any individual overrun accident by providing real-time data to the pilot. FOQA is a data-analysis program which provides feedback on daily operations through data analysis. This kind of event is just one in a huge toolbox of events which, when fed back to operations and pilots, help determine and validate training priorities, SOPs, operational techniques and associated risk factors.

That said, the results of this particular event are very interesting and can help pilots understand the risks of non-stabilized approaches, long landings and the risks of overrun, especially now in winter ops.

PJ2

[OverRun]

Interesting discussion - thanks for the informative discussion. There was some nice work done by Kirkland, Caves, Humphreys and Pitfield in 2004 which allowed a relative probability of overrun events to be assessed. Basically the probability of an overrun can be found in terms of how much distance is left on the runway after the required accelerate-stop or landing distance.

If there are only a few hundred metres (yards) extra, then the relative probability of an overrun rises. If the runway is long and well beyond that needed for takeoff/landing, then the relative probability of an overrun drops away sharply. Nothing new there, but it is nice to be able to quantify the risk and relate that to the need for specific engineering action.



The graphic comes from a paper looking at the need for a runway surface friction layer using this methodology at Risk_friction_layer_AMS_2009

Cheers,
Overrun

[bburks]

Alaska Airlines operated into Dutch Harbor at 3900', but by then it was paved. This was in the 737-200 advanced with JT8D-17 engines and heavy brakes. Before Alaska Airlines, MarkAir operated the same B-737-200 advanced, but started ops with a 3900' gravel runway, no over-run, and no VASI's. The approach was a contact approach using NDB/DME to an MDA of 660'.

When the -200's were retired, so were DUT operations in the jet.

Alaska now operates into longer runways using B-737-400's (and occasionally the 700/800) but several are still around 5000'; Nome, Kotzebue, Deadhorse, Barrow, Dillingham, Bethel, King Salmon, Kodiak, Gustavus, Petersburg and Wrangell. In the loser 48, shortest ops are into Orange County and Burbank and 5500' or so.

[fireflybob]

Going to BHD one day cabin crew remarked "the runway's a bit short there isn't it?"

I replied "so long as we obey the rules and fly the aircraft correctly it's long enough!"

[Desert185]

...and then there is runway clutter with limited braking action or other MEL/CDL issues. I would look at airport analysis for airports with varying runway lengths to get an idea of your aircraft's landing distance requirements at differing weights.

Always nice to have an idea of runway landing distance required should one have to divert enroute when airport analysis might not be readily available.