My city's mayor was just boasting on how she'd gotten an approval for an airport runway of length "2100 m gross, 1900 m net length", and that this would be enough to connect the city - Haifa - to hubs all across Europe.

I'm not sure what she meant exactly, but I looked up some aircraft runway requirements, and found this, with no distinction between "gross" and "net" length. Now, some of the Boeing 737 models can fit the "net" length she mentioned, and so can Airbus A319's - but A320s or A321s fall right between the "net" and "gross" lengths.

So, my question is:

  • Is there such a thing as "gross" vs "net" runway length? If so, what counts into the gross but not the net? Clear space between the tarmac and the perimeter fence maybe?
  • Was the mayor making an empty boast or can the information about that runway be interpreted so that what she said is correct?

Gross and net are not aviation terms for runways. Many runways have extra space on either end to be used as stopways, giving extra stopping distance in case of an overrun.

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I'm going to hazard a guess and say that the gross length is the total paved area of the runway and the net length is between the thresholds that is usable for takeoffs and landings.

  • $\begingroup$ and the aircraft requirements are of "net" runway, I assume? $\endgroup$
    – einpoklum
    Mar 1 '20 at 23:16
  • $\begingroup$ Normally yes @einpoklum $\endgroup$
    – GdD
    Mar 1 '20 at 23:24
  • 2
    $\begingroup$ Wouldn't 'net' be between the threshold for that direction and the far end of the runway? (And presumably the whole length for takeoff). $\endgroup$
    – Zeus
    Mar 2 '20 at 1:45
  • $\begingroup$ That's exactly what I'm saying @Zeus, net is the distance between the thresholds. $\endgroup$
    – GdD
    Mar 2 '20 at 22:24

According to Wikipedia, Haifa Airport's runway is currently 1318m long, with plans to extend it by 316m to 1634m. None of those numbers match your question.

The terms "gross" and "net" aren't used in this context, but we do talk about "total" and "available" (or "usable") length, which could just be a translation issue. Runways often have a "displaced threshold", which means planes aren't allowed to land at the beginning of the pavement but rather starting some distance beyond. In the case of Haifa, the threshold for runway 16 is displaced by 50m (leaving only 1268m available) and runway 34 by 119m (leaving only 1199m available). The full length is available for takeoffs. This is extremely short and will indeed severely limit what planes can land there.

The plan is to extend the runway by putting the road at one end into a tunnel. Not only will this increase the total length of the pavement, but it will reduce (or maybe even eliminate) the need for displacement, further increasing how much of the pavement is available. This is still fairly short and limiting by commercial airport standards, but it is still a significant improvement and perhaps enough to make flights to Europe viable for airlines.

  • $\begingroup$ Wikipedia might not be up-to-date on this - especially in English. $\endgroup$
    – einpoklum
    Mar 2 '20 at 8:16
  • $\begingroup$ @einpoklum I checked a translation of the Hebrew version, and that listed past plans to increase to 2000m and 2400m, but both were rejected by national authorities and the 1600m plan is the one currently on the books. $\endgroup$
    – StephenS
    Mar 3 '20 at 4:09
  • $\begingroup$ There was this more recent video interview where the mayor said what I quoted her as saying. But who knows. $\endgroup$
    – einpoklum
    Mar 3 '20 at 8:11

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