Chapter A07 - Autoland Flashcards
The purpose of an autoland system, which has to be used together with an Instrument Landing System (ILS), is to enable aircraft to
make safe approaches and landings in weather conditions that would not otherwise be possible.
The height that an aircraft can descend to on an ILS before becoming visual and landing is governed by five main factors:
- Weather conditions
- Runway and airfield location and facilities
- Aircraft performance and equipment fit
- Pilot training
- Operators approval
We need atleast ? systems for autoland
Two systems (autopilot)
The weather limits for an autoland landing are given in the following terms:
- Runway Visual Range (RVR): the range at which high intensity lights can be seen in the direction of the landing along the runway.
- Decision Height (DH): height above the runway threshold by which a go- around must be initiated by the pilot unless adequate visual reference has been established, and the position and approach path of the aircraft have been visually assessed as satisfactory to safely continue the approach or landing.
What are the autoland components?
Autopilot, Autothrust, Radio Altimeter, ILS Receivers
What is Fail operational?
A system capable of completing an operation, following the failure of any single element or component of that system, without pilot action.
What is Fail passive?
a system which, in the event of a failure, results in:
- No significant deviation in the aircraft flight path or attitude, and
- No out-of-trim condition at disengagement that is not easily controlled by the pilot.
With 2 autopilots, a Fail Passive system exists. Should one autopilot fail, the other autopilot remains engaged but no _____ . The pilot needs to perform a landing or go-around manually.
- autoland ability exists
Fail-Operational Hybrid Landing System - a system that consists of a _____ automatic landing system and a secondary independent guidance system enabling the pilot to complete a landing manually after failure of the primary system.
- primary fail-passive
Autopilot with HUD
What is Alert Height ?
If a failure occurs below AH, it is considered safer to ignore the failure and continue the approach. Above alert height, the pilot would normally carry out a missed approach.
Failures below AH prompting a go-around would have to be serious, and might include:
- The loss of all autopilots.
- Loss of ILS signal.
- Loss of ILS functionality (e.g. NAV failure)
- Radio altimeter failure.
- Excessive ILS deviation.
How would you prepare for an autoland approach? 6 Bs
Boxes, Bearings, Bugs, Brakes, Briefing, Back end
At 1500 ft RA, the ________. FLARE mode becomes armed, and green CMD is displayed indicating ______ has engaged.
- second autopilot engages
- second autopilot
50 ft RA _____ mode becomes active
FLARE
At 27 ft RA, _____ mode engages and autothrottle retards the thrust for touchdown
RETARD
Autothrottle disengages ______ touchdown or when reverse thrust is used.
2 seconds after
How does rollout mode maintain centreline?
maintains centreline using rudder and nosewheel steering
Where fitted, ROLLOUT continues to provide
- lateral guidance to the aircraft
after touchdown.
In the event of a failure, a fail-operational flight control system will operate as a:
Fail-passive system
When an autoland system (autopilot) is described as fail operational it is:
Fail safe
A flight control system is fail-operational if, in the event of a failure:
The approach, flare and landing can be completed automatically
Can you still land with a fail-passive system?
Yes
Concerning a fail-passive flight control system, in the event of a failure:, does it still remain in trim?
YES - It will fly you into the ground in trim
A flight control system is fail-passive if, in the event of a failure:
There is no significant out-of-trim condition or deviation of flight path or attitude but the landing is not completed automatically
An automatic landing system which can keep on operating without deterioration of its performances following the failure of one of the autopilots is called “FAIL…:
OPERATIONAL
During a Category II automatic approach, the height information is supplied by the:
Radio altimeter
