CoolGuy From United States of America, joined Jan 2005, 410 posts, RR: 0 Posted (6 years 3 months 3 weeks 6 days 15 hours ago) and read 1916 times:
RY 13 VASI AND ILS NOT COINCIDENTAL (I know what VASI and ILS are but what does this mean?)
RY 13 300 FT CLEARWAY
B747-400 AIRCRAFT RESTRICTED TO 10 KNOT TAXI SPEED ON ALL TAXIWAYS (I know what that means, but what's the reasoning?)
Corey07850 From United States of America, joined Feb 2004, 2522 posts, RR: 5 Reply 2, posted (6 years 3 months 3 weeks 6 days 14 hours ago) and read 1900 times:
Meaning if you are say, flying the ILS and are dead on glideslope, you may not appear to be on glideslope according to the VASI. FAA Navaid engineers have told me that when VASI's were installed many years ago the ground they were installed on wasn't prepared as well as it should have and it's very common to have a VASI setup slowly sink into the ground, causing the angles to slightly shift.
CoolGuy From United States of America, joined Jan 2005, 410 posts, RR: 0 Reply 3, posted (6 years 3 months 3 weeks 6 days 13 hours ago) and read 1894 times:
Is it even possible for a B747-400 to take off from the 7000ft runways at LGA (I know that's fine for landing)?
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 4, posted (6 years 3 months 3 weeks 6 days 13 hours ago) and read 1885 times:
I don't understand how limiting taxi speed alleviates ramp congestion. Further, what's the logic behind limiting the taxi speed of only large aircraft?
Maybe I'm just getting sleepy, but I don't understand...
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 10 Reply 5, posted (6 years 3 months 3 weeks 6 days 13 hours ago) and read 1880 times:
Quoting 2H4 (Reply 4): Further, what's the logic behind limiting the taxi speed of only large aircraft?
Having seen a 767-400 taxi around La Guardia, I don't think you would want to taxi any faster than that. Not only are the wing tip clearences tight, bit the main gear to taxiway edge margin is tight as well. I don't know how it will alleiviate congestion though.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 6, posted (6 years 3 months 3 weeks 6 days 13 hours ago) and read 1877 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
I wonder if limiting the speed of large/heavy aircraft is in any way related to reducing the pavement loading. If, for example, an aircraft is right at the maximum weight/pavement loading limit, braking and/or turning at higher speeds could transfer quite a bit of weight onto one landing gear...perhaps causing damage to the taxiway or ramp.
PhilSquares From , joined Dec 1969, posts, RR: Reply 7, posted (6 years 3 months 3 weeks 6 days 12 hours ago) and read 1861 times:
Quoting 2H4 (Reply 6): I wonder if limiting the speed of large/heavy aircraft is in any way related to reducing the pavement loading. If, for example, an aircraft is right at the maximum weight/pavement loading limit, braking and/or turning at higher speeds could transfer quite a bit of weight onto one landing gear...perhaps causing damage to the taxiway or ramp.
No....
The issue on the taxi speed is purely due to ramp congestion, narrow taxiways. They (PANY) just want to make sure people are extra vigilant.
Boeing7E7 From , joined Dec 1969, posts, RR: Reply 8, posted (6 years 3 months 3 weeks 6 days 12 hours ago) and read 1859 times:
Quoting 2H4 (Reply 6): I wonder if limiting the speed of large/heavy aircraft is in any way related to reducing the pavement loading. If, for example, an aircraft is right at the maximum weight/pavement loading limit, braking and/or turning at higher speeds could transfer quite a bit of weight onto one landing gear...perhaps causing damage to the taxiway or ramp.
To create more space to park delayed aircraft, LGA reduced their taxiway separations to a hybrid centered on the 767. They use "taxilane" separation standards vs. "taxiway" separation standards for taxiways not associated with runway access. As such, what would normally be 187' of separation (centerline to centerline between taxiways) is instead 172' feet . This leaves enough wingtip clearance, but not as much as one would desire. The result is slower taxi speeds for larger aircraft to reduce incident potential.
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 9, posted (6 years 3 months 3 weeks 6 days 4 hours ago) and read 1815 times:
B747-400 AIRCRAFT RESTRICTED TO 10 KNOT TAXI SPEED ON ALL TAXIWAYS
That's actually a typo... should be 767-400
i've personally seen the DL 764s taxi faster than that, and have stood under the singtip as it passed overhead while the airplane taxiied by on A.
Quoting 2H4 (Reply 6): I wonder if limiting the speed of large/heavy aircraft is in any way related to reducing the pavement loading. If, for example, an aircraft is right at the maximum weight/pavement loading limit, braking and/or turning at higher speeds could transfer quite a bit of weight onto one landing gear...perhaps causing damage to the taxiway or ramp.
Just thinking out loud....
it is. the reason they are restricted is more for the piers that support the ends of runways 4 and 13. taxiing faster than that would out stress on the piers and could lead to the junction between the pier and the taxiway bed breaking. what interesting is the types of airplanes that are restricted from even landing. the 707 and DC-8 are not allowed to land at LGA due to "landing gear loading.'' what's strange is that a 737-800 and 707 aren't that far apart in weights while the 737 has 4 less wheels to distribute the weight.
"...cannot the kingdom of salvation take me home."
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 11, posted (6 years 3 months 3 weeks 5 days 22 hours ago) and read 1710 times:
AIRLINERS.NET CREW HEAD DATABASE EDITOR
Quoting Cancidas (Reply 10): the 707 and DC-8 are not allowed to land at LGA due to "landing gear loading.''
I thought the 727 had the highest landing gear loading of any airliner.....
2H4 From United States of America, joined Oct 2004, 8950 posts, RR: 62 Reply 14, posted (6 years 3 months 3 weeks 4 days 19 hours ago) and read 1588 times:
OPNLguy From , joined Dec 1969, posts, RR: Reply 15, posted (6 years 3 months 3 weeks 4 days 19 hours ago) and read 1585 times:
Quoting 2H4 (Reply 14): I can't remember where I read it, but I remember seeing more than one source claim the 727 had the "honor"...
At Air Florida, we had some 727-200s with -17R engines, with max takeoff weights of just over 200,000 lbs, but at LGA, the "pier limit" knocked that down to 176,000 lbs... A pretty big hit....
3DPlanes From United States of America, joined Apr 2006, 167 posts, RR: 0 Reply 16, posted (6 years 3 months 3 weeks 4 days 16 hours ago) and read 1539 times:
Isn't the "pier issue" more to do with weight per area rather than weight per gear? I'm sure wheel or gear loading are also important, but I thought the issue with the 767 was the amount of weight over a certain distance - hence the reason for changing the gear spacing vice adding more wheels.
Though I don't have the numbers to look at, that might explain the reasoning behind the 737 vs 707 difference above. More wheels lessens the psi loading, but if the bogies where further apart, that might allow them to spread across more piers.
Sponsor Message: 
From United States of America, joined Jan 2005, 410 posts, 
From , joined Dec 1969, posts, 
From Poland, joined Jul 2003, 4112 posts, 
From Canada, joined Jan 2001, 140 posts, 
Sponsor Message: 
Printer friendly format
