When you press the (L NAV) Switch
- LNAV engages if the airplane is above 50’ RA and
- within 2.5 NM of the active leg
- if not within 2.5 NM of the active leg and on an intercept heading to the active leg, remains armed then engages when approaching the active leg
When will LNAV deactivate?
- (HDG HOLD) or heading select (HDG SEL)
- when localizer is captured
- if there is a dual FMC failure
- by pushing L NAV switch a second time when LNAV is armed
VNAV deactivates when…
- selecting GA, FL CH, SPD or THR, V/S or ALT HOLD
- pushing VNAV switch a second time when VNAV is armed
- in climb or descent, reaching altitude displayed in altitude window prior to reaching FMCs target altitude
- passing top of descent point if the MCP is not set to an altitude below cruise altitude
- when glideslope is captured
What happens concerning thrust when Flight Level Change (FL CH) Switch is pressed?
Changes thrust reference from TO to CLB if above 400 feet radio altitude.
When you press the LOC switch, explain capture?
Localize capture can occur when intercept track angle is within 120 degrees of the localizer course.
Note: After localizer capture, flight director roll commands may appear inconsistent with A/P roll maneuvers for one to two minutes.
Describe the Autoland Status Annunciator?
Upper window
LAND 3 – (green)
LAND 2 – (green)
What is LAND 3 ?
LAND 3 – (green)
- indicates all three autopilot systems with their airplane system inputs are operating normally
- appears below 1500 feet radio altitude with LOC and G/S captured
What is LAND 2 ?
LAND 2 – (green)
- indicates a minimum of two autopilot systems with their airplane system inputs are operating normally.
- appears below 1500 feet radio altitude with LOC and G/S captured
Describe the Autoland Status Annunciator?
Lower window
NO AUTOLND (amber)
NO LAND 3 (amber)
What is NO AUTOLND?
NO AUTOLND (amber) – indicates fault conditions exist which preclude the use of the autopilots for an automatic landing.
What is NO LAND 3?
NO LAND 3 (amber) – indicates a fault condition exists which results in a LAND 2 condition.
Pushing either GO AROUND Switches does what?
- engages AFDS and autothrottle in GA mode if previously armed
- provides windshear guidance during GA mode if previously armed
- if flight director off, activates flight director in GA mode
- cancels all thrust derates if selected after takeoff
When does the Go around Arm?
• automatic arming occurs at glide slope capture or extension of wing flaps
Autopilot (AUTO PILOT) Light
Illuminated (amber) –
- a degraded operating condition exists in engaged autopilot
- extinguished when condition is corrected or
- an alternate autopilot is selected, provided fault is not common to alternate autopilot
Describe the
AUTOMATIC FLIGHT CONTROL SYSTEM
The automatic flight control system consists of the
autopilot flight director system _(AFDS)_
autothrottle system _(A/T)._The mode control panel (MCP) and flight management
computer (FMC) control the AFDS and the autothrottle
system to perform climb, cruise, descent and approach.
The Autopilot Flight Director System
The AFDS consists of______flight control computers (FCCs) and the_______?
The AFDS consists of three flight control computers (FCCs) and the MCP.
Describe the Autopilot Flight Director System
The three FCCs, left, center, and right, control separate hydraulically powered autopilot control servos to operate flight controls.
The autopilot controls ailerons and elevators.
Rudder commands are added only during a multiple autopilot approach.
Nose wheel steering is also added during rollout from an automatic landing.
During an ILS approach with all three autopilots engaged, separate electrical sources power the three FCCs.
What are the indications of a flight director failure?
A flight director failure in either pitch or roll, causes the respective steering bars to disappear
What conditions cause the FD display to occurr
The steering indications are displayed when
the related flight director switch is OFF and
a go–around switch is pushed,
if airspeed is greater than 80 knots and
the flaps are not retracted.
