I notice in the FRF KJFK scenery that Rwy 4L/22R has 2500 ft "displaced threshold" on either end. What's the purpose for this?I can understand if there were mountainous terrain but it's pretty flat in this area. How does it affect the AI or user aircraft if the displacement is removed?Just a curiousity question.Thanks

I think only 22R has a displaced threshold IRL. I assume there is an obstacle in the 22R approach that forced it.scott s..

I notice in the FRF KJFK scenery that Rwy 4L/22R has 2500 ft "displaced threshold" on either end. What's the purpose for this?I can understand if there were mountainous terrain but it's pretty flat in this area. How does it affect the AI or user aircraft if the displacement is removed?Just a curiousity question.Thanks

From Wikipedia:Most often the offset threshold is in place to give arriving aircraft clearance over an obstruction while still allowing departing aircraft the maximum amount of runway available. A displaced threshold may also be introduced if a beginning section of the runway is no longer able to sustain the continuous impact from landing aircraft. In such a case, aircraft are expected to land beyond the displaced threshold. Departing aircraft are permitted to use the displaced section of the runway for takeoffs or landing rollouts because those aircraft are not impacting the runway with the force of a landing aircraft.Another article I read stated that it is most often seen at both ends of a runway. Google is indeed our friend! :(

I always look at the runway data from an AFD or in this case, AIRNAV.http://www.airnav.com/airport/KJFKListed for Runway 22R, there is an obstruction listed. I'm not sure that is the ONLY reason for the displaced threshold but its a start.I like to look at these on GOOGLE Earth, which I am attempting now.Regards,Jim