Ba299 From United Kingdom, joined Jun 2003, 173 posts, RR: 1 Posted (12 years 6 months 2 weeks 1 day 7 hours ago) and read 3971 times:
Yesterday I read a notam for JFK airport about a new RNAV SID. It refer to DME/DME mode for the update the FMS position.
Now I know that our 777 use the DME/DME mode but what about the "oldest" aircraft such as the 767? How the 767 update the position?
On the 777 we use the DME/DME mode and the GPS/IRU as back-up. Is it the INS the main mode on the 767?
Yikes! From Canada, joined Oct 2001, 284 posts, RR: 1
Reply 1, posted (12 years 6 months 2 weeks 1 day 4 hours ago) and read 3933 times:
Primary nav on the 767 is by radio updating. This can occur only once airborne but is very quick in areas of good rho/rho coverage. If the aircraft commences its takeoff with a map shifted position, the RNAV may be inaccurate during a noise sensitive phase of the flight as the shift from IRS position to radio updating position can cause the aircraft to deviate its flight path when it's just too close to those darn microphones.
Lots of noise violations occur for this simple reason.
Don't know about the 777 but I think I heard they beat this problem out of that system prior to building it.
Ba299 From United Kingdom, joined Jun 2003, 173 posts, RR: 1
Reply 2, posted (12 years 6 months 2 weeks 20 hours ago) and read 3903 times:
here the notam about kjfk:
KJFK APT 20030151466V02 01/053 WIE / UFN
JFK PELUE TWO DEPARTURE...
PUBLIC RNAV DEPARTURE PROCEDURES AND STAR, FOR /E, /F, /G AND /R
A.RNAV DEPARTURES AND STARS. PILOTS OF AIRCRAFT UTILIZING DME/DME
FOR PRIMARY RADIO UPDATING SHALL ENSURE ANY PUBLISHED REQUIRED DME
STATIONS ARE IN SERVICE AS DETERMINED BY NOTAM, ATIS OR ATC
B.RNAV DEPARTURES. /E, /F AND /R AIRCRAFT CONDUCTING PUBLISHED RNAV
DEPARTURES AND NOT USING GPS NAVIGATION OR GPS UPDATING OF FMS
MEET THE FOLLOWING REQUIREMENTS:
I. PRE-TAXI ALIGNMENT REQUIREMENT: FULL INITIAL INERTIAL/NAVIGATION
SYSTEM ALIGNMENT SHALL BE ACCOMPLISHED USING GATE, PARKING SPOT, OR
AIRPORT REFERENCE POINT COORDINATES.
II. PRE-DEPARTURE UPDATE REQUIREMENT: ACCOMPLISH ONE OF THE FOLLOW-
1) RUNWAY UPDATE (AUTOMATIC OR MANUAL).
2) INERTIAL/NAVIGATION SYSTEM QUICK ALIGNMENT WITHIN 1000 FEET OF A
CHARTED WAYPOINT, WHICH IS RETRIEVABLE FROM THE ONBOARD NAVIGATION
DATABASE, WITHIN 30 MINUTES PRIOR TO TAKEOFF. NOTE: DO NOT PERFORM
QUICK ALIGNMENT ON THE RUNWAY.
III. IN-FLIGHT RADIO UPDATE: RADIO UPDATING MUST COMMENCE WITHIN 10
FLYING MILES FROM THE DEPARTURE END OF THE RUNWAY. IF NOT EQUIPPED
WITH GPS, /E, /F AND /R AIRCRAFT MUST BE CAPABLE OF NORMAL PRIMARY
NAVIGATION UPDATING IN THE TERMINAL AREA USING IRU/DME/DME. AIR-
CRAFT, WHICH UTILIZE VOR/DME FOR NORMAL PRIMARY NAVIGATION
ARE NOT AUTHORIZED.