Runway Lengths

There is the overruns and then theres things such as displaced thresholds. It can get very confusing as to how long a runway actually is.

Peter wrote:

I have never understood why discussions occur over runway lengths as its easily solved with online maps and aerial photos. Or is the issue with the overrun areas?

By the way, Wittering was the longest in the UK at 4,800 yards and that was when it was grass in 1942!

Yes Wittering was extended to include Collyweston and one other airfield; I read somewhere they tested Me 163 airframes there post war but without fuel, just towed!

Captain Eric Brown mentions testing the Komet landing skid at Wittering in ,"Wings on my Sleeve"-

He says that the wartime runway had been 5 miles long but had been reduced to 3 by the time he was there post war-5 miles does seem rather long,perhaps a publishing error...

He also quotes the Wittering strip as being one of the 3 wartime Emergency Landing Grounds(Carnaby,Manston,Woodbridge) specially constructed for crippled aircraft.

The long Wittering strip had originally been constructed to reduce night fighter Beaufighter landing accidents.Sir Basil Embry("Mission Completed") indicated that he thought the 3 ELG's were built after some 70 aircraft had found refuge at the long grass airstrip at Wittering.

Dr.Roland Winfield describes a visit to Newmarket Heath airfield in his excellent book,"The sky belongs to them"-It was used by a flight of aircraft to drop SOE agents over the continent before expanding to 2 squadrons and transferring to Tempsford.

canberra wrote:

There is the overruns and then theres things such as displaced thresholds. It can get very confusing as to how long a runway actually is.

Those SAC runways were designed for B47s so they had to be long; the main airbrake was a small parachute deployed when established on final to stop the speed getting too high and once deployed, it wasn't easy to adjust rate of descent to 'hit' a specific touchdown point, the main brake chutes being streamed after touchdown.

This is where runway lengths get confusing. Leuchars runway 27 was 8491 feet long, the reciprocal is of course 09 and how long is that? Well heres where it can get confusing, 09 has a displaced threshold due to the public road in the undershoot and is 7500 feet long for landing, this is called the LDA or landing distance available. Most people referred to 09 as being 7500 feet long, but of course for take off or Take Off Distance Available its 8491 feet.

canberra wrote:

This is where runway lengths get confusing. Leuchars runway 27 was 8491 feet long, the reciprocal is of course 09 and how long is that? Well heres where it can get confusing, 09 has a displaced threshold due to the public road in the undershoot and is 7500 feet long for landing, this is called the LDA or landing distance available. Most people referred to 09 as being 7500 feet long, but of course for take off or Take Off Distance Available its 8491 feet.

Whilst 8491 (I've seen it quoted as 8494) is the total length of paved surface normally available, the actual lengths used by aircraft can differ firstly as you say with a displaced threshold, this length being LDA.
Then you have:
TORA (Take off run available) the length available for takeoff which may be less than total length if the 2% takeoff/climb surface (TOCS which takes into account any obstructions in the takeoff climbout area) ) intercepts the runway before the end
TODA (Take off distance available) which is TORA plus clearway, where the clearway is a defined rectangular area at the end of the takeoff run over which an aircraft may make its initial climb, the length of this being as far as the first significant obstacle.
ASDA (Accelerate/ stop distance available) which is TORA plus the stopway where the stopway is an area at the end of the TORA for emergency use only ie rejected or aborted takeoffs - it may not have the same load bearing strength as the rest of the runway hence is not used in takeoff calculations.
The UK Military AIP quotes Leuchars as :
LDA 08 - 2317m /7599ft LDA 26 - 2586m/8482ft
TORA 08 - 2586m TORA 26 - 2586m
TODA 08 - 2823m TODA 26 - 2628m giving a clearway of 237m on 08 and 42m on 26.
ASDA 08 - 2768m ASDA 26 - 2628m which gives stopway 08 as 182m and stopway 26 as 42m.

If you want to see what other military airfields quote, the Military AIP is available at www.aidu.mod.uk/aip/aipVolumes.html#ad-tab
Sorry I inadvertantly posted an incorrect link, it should work now.
Interestingly, although I've taken the above figures from the textual data, the airfield chart shows total paved length (excludung stopways) as 2811m/9221ft!