Faro From Egypt, joined Aug 2007, 1443 posts, RR: 0 Posted (3 years 9 months 3 weeks 5 days 16 hours ago) and read 3653 times:
In the following pic off the database, why the displaced threshold if your approach is over a water surface? Where is your obstacle; don't understand...
KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 1, posted (3 years 9 months 3 weeks 5 days 16 hours ago) and read 3635 times:
Maybe on the other end of the lake (after all, this is in Dallas, Texas, a very land-locked city!)
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 3, posted (3 years 9 months 3 weeks 5 days 15 hours ago) and read 3607 times:
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Quoting Faro (Thread starter): why the displaced threshold if your approach is over a water surface? Where is your obstacle; don't understand...
I wonder if shipping lanes (at other airports) might justify displaced thresholds for clearance above passing ships.
Vikkyvik From United States of America, joined Jul 2003, 8200 posts, RR: 28 Reply 4, posted (3 years 9 months 3 weeks 5 days 14 hours ago) and read 3596 times:
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Quoting 2H4 (Reply 3): I wonder if shipping lanes (at other airports) might justify displaced thresholds for clearance above passing ships.
Look at the info for runway 4R-22L and 22R at BOS:
MSNDC9 From , joined Dec 1969, posts, RR: Reply 5, posted (3 years 9 months 3 weeks 4 days 19 hours ago) and read 3451 times:
Quoting Faro (Thread starter): In the following pic off the database, why the displaced threshold if your approach is over a water surface? Where is your obstacle; don't understand...
You still have a runway safety area requirement "before" the threshold which is 600-feet. Water cannot serve as an RSA beyond the runway, so in terms of lighting layouts, distance remaining markings and needs of an RSA of 1,000-feet in that area (going the other direction), they probably made it 1,000-feet to make it even then applied declared distances. It also has the unusual 3,000-foot ALS vs the standard 2,400-foot.
They did a similar thing at the other end. The threshold is even with a 1,000-foot RSA to the property line.
Boeing767mech From United States of America, joined Dec 2000, 992 posts, RR: 3 Reply 6, posted (3 years 9 months 3 weeks 4 days 16 hours ago) and read 3388 times:
[quote=Vikkyvik,reply=4]
Quoting 2H4 (Reply 3):
I wonder if shipping lanes (at other airports) might justify displaced thresholds for clearance above passing ships.
Look at the info for runway 4R-22L and 22R at BOS:
I have been out doing engine runs at the end of a closed runway here in BOS and heard the controllers tell the inbound airplanes to go around due to a Oil Tanker in the channel on the approach end of 22L and 22R.
EcuadorianMD11 From , joined Dec 1969, posts, RR: Reply 7, posted (3 years 9 months 3 weeks 4 days 11 hours ago) and read 3318 times:
I remember towing an oil rig (jack up) through Singapore Straits and the vessel traffic controller was pretty anxious for us to report our position at a particular point to tell Changi Airport in time.
If you catch a jetliner with the legs of an oilrig..........I guess you´d make the headlines!
Eternal fame.........
Woodreau From United States of America, joined Sep 2001, 890 posts, RR: 7 Reply 8, posted (3 years 9 months 3 weeks 2 days 19 hours ago) and read 3138 times:
Quoting MSNDC9 (Reply 5): You still have a runway safety area requirement "before" the threshold which is 600-feet. Water cannot serve as an RSA beyond the runway, so in terms of lighting layouts, distance remaining markings and needs of an RSA of 1,000-feet in that area (going the other direction), they probably made it 1,000-feet to make it even then applied declared distances. It also has the unusual 3,000-foot ALS vs the standard 2,400-foot.
They did a similar thing at the other end. The threshold is even with a 1,000-foot RSA to the property line.
I was thinking along the same lines as you were with respect to the runways safety area and approach lighting.
At first I thought there might be high voltage transmission lines just south of the runway - there aren't any. However, what the photo doesn't show is that there is a radio/television tower antenna farm perched on a hill about 6-7 miles south along the extended centerline with several antennae - I think around 4 or 5 - that go up to 2500ft above the touchdown zone elevation. Given that a 3 degree ILS glideslope is 300ft / nm - it might affect the threshold, but I don't think that in itself determines the displaced threshold - the antennae would just interfere with any instrument approaches from the south.
This particular runway is closed but the city has elected to continue maintaining the runway in the event it is needed again. I believe Vought Aircraft still does use it to fly parts in and out of the production facility.
[Edited 2009-07-31 10:29:51]
Good judgement comes from experience. Experience comes from surviving bad judgement.
KELPkid From United States of America, joined Nov 2005, 5929 posts, RR: 4 Reply 9, posted (3 years 9 months 3 weeks 2 days 18 hours ago) and read 3121 times:
Quoting Woodreau (Reply 8):
At first I thought there might be high voltage transmission lines just south of the runway - there aren't any. However, what the photo doesn't show is that there is a radio/television tower antenna farm perched on a hill about 6-7 miles south along the extended centerline with several antennae - I think around 4 or 5 - that go up to 2500ft above the touchdown zone elevation. Given that a 3 degree ILS glideslope is 300ft / nm - it might affect the threshold, but I don't think that in itself determines the displaced threshold - the antennae would just interfere with any instrument approaches from the south.
IIRC, in the 1980's, an F-14 had an unfortunate encounter with one of the towers (a TV station maintained by late former boss and flight instructor)...maybe this is what lead to the displaced threshhold. I don't remember the details, but I think the flight crew was killed, and a TV station had to operate with an emergency authorization from the FCC (which allowed them to temporarily relocate their transmitter to an adjacent tower at a lower height) until their tower could be reconstructed...
Celebrating the birth of KELPkidJR on August 5, 2009 :-)
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(after all, this is in Dallas, Texas, a very land-locked city!)
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