Runway Lengths
 

Is there a standard length of runway that a commercial airport must have to accomodate jets? It seems to me that every airport seems to have differnt runway lengths. Is it just because of space????

The length required is for specific aircraft and depends on the altitude, temperature and weight of the aircraft, not to mention runway conditions (braking action, etc.) Airports build them large enough to accomodate the aircraft which need to land there. Some airports have shorter runways and cannot accomodate larger aircraft - LGA, for example. Clearly lack of space is a factor which inhibits expansion of runways to accomodate larger aircraft or more frequent flights.

If you are interested, World Airport Codes is an online tool you can use to check out runway lengths at your favourite airports.

That site is kinda basic. For better information in the US try airnav.com or worldaerodata.com.

Lengths and widths
 

Hi,

The airport may use planning manuals to determine the relevant runway lengths for the type of aircraft expected to use the airport. Also the Pavement Classification Number for strength. You can dig around in the Boeing and Airbus sites for these public documents if you want. Try Airport Planning Manual as keyword. Also things like hydrant location and ground vehicle access will be there.

For take off, you will find that if the runway is a limiting length, then payload, such as fuel, passengers, cargo and baggage has to be off loaded. This can occur with extreme high temperatures, lack of wind, low pressure or very high elevations. Sometimes, the initial climb over obstacles limits the operation as well.

For landing, it is the location of the nominal touchdown point, the landing mass, head/tailwind and braking action that are the important factors. For big aircraft, they can usually stop shorter than they can take off. You can stop a 747-400 in around 1400-1500 metres of runway, but that takes Autobrake 6, from memory and do not touch the brakes afterwards, they will be hot, hot hot. Hot brakes might equal a long turn around time to get them cool enough to take the rejected take off energy. Some operators will use maximum reverse thrust just to reduce the brake temperature, a little, to shorten turn around times.

The key terms are Landing Distance Available, Take Off Run Available, Take off distance available (difference between the last two is that one is runway length usable for take off, the other is the distance to the first significant upstanding obstacle) and Accelerate Stop Distance Available (or Emergency Distance Available) which is for the rejected take off case.

You may get starter strips, which can be used for take off but not landing (with a displaced threshold) or stopways (the opposite).

If a runway is over-long for departures, then they can do reduced thrust take off to save engine wear, noise and fuel.

Is that a start. PM if you need more.

Spotwelder