High Latitude Alignment
This procedure should be followed when aligning the IRS systems at latitudes greater than 70° 12.0 and less than 78° 15.0.
IRS mode selectors.......................................................................ALIGN
Position Initialization page..................................................................Set
Enter present position on SET IRS POS line using the most accurate latitude and longitude available. The IRS mode selectors must be in ALIGN for a minimum of 17
minutes. IRS mode selectors...........................................................................NAV
IRS Entries Present Position Entry
IRS mode selector ............................................................................NAV
ALIGN lights must be illuminated (steady or flashing).
IRS display selector ........................................................................PPOS
Latitude ............................................................................................Enter Key–in latitude in the data display, beginning with N or S, then press the ENT Key (the Cue Lights extinguish).
Longitude .........................................................................................Enter Key–in longitude in the data display, beginning with E or W, then press the ENT key (the cue lights extinguish). Observe that proper latitude and longitude are displayed and that the ALIGN light is not flashing.
Heading – ENTER Through CDU
FMC/CDU POS INIT page ............................................................ Select Enter the correct heading into the CDU scratch pad then press line select key 5R. Verify entered heading appears on line 5R. Select HDG on the IRS display selector and verify that the entered heading is displayed on the ISDU, RDMI's and HSI's.
Copyright . The Boeing Company. See title page for details.
SP.11.4 December 3, 2004
Supplementary Procedures -Flight Management, Navigation 737 Operations Manual
Heading – ENTER Through IRS Mode Selector Panel
IRS display selector ......................................................................... HDG Press the H key to initiate a heading entry. Key–in present magnetic heading. Press the ENT key (the cue lights
extinguish). Observe proper heading displayed on the RDMI's and
HSI's.
Inadvertent Selection of Attitude Mode (while on the ground)
Inadvertent selection of the attitude mode may be due to physically overpowering the switch during turn–on, or the result of a faulty switch where the flight crew cannot accurately determine which mode is selected. If the ATT position is selected inadvertently when switching to NAV, the IRS must be turned off, and after the ALIGN lights extinguish, a full alignment must be initiated.
Navigation/Flight Management Lateral Navigation Using the FMC/CDU Proceeding Direct To a Waypoint or (U5) Intercepting a Leg (Course) to a
Waypoint (overwrite)
RTE LEGS page .............................................................................Select
On page 1/XX, line 1L, enter the desired waypoint over the presently active waypoint.
(U5 and on) Observe INTC CRS prompt in line 6R.
(U5 and on) If intercepting a leg to the waypoint, enter the desired intercept course in the INTC CRS line. Correct any ROUTE DISCONTINUITY if the entered waypoint was
not in the original flight plan.
EXEC key.........................................................................................Push Observe the MOD RTE LEGS page changes to ACT.
(U5 and on) LNAV may disengage after execution of an intercept leg to a waypoint. If LNAV disengages, turn to a heading to satisfy LNAV capture criteria.
Supplementary Procedures -Flight Management, Navigation 737 Operations Manual
