1 Reliability
Certification flight test data may need to be supplemented by either in-service data or analysis to establish the required level of reliability.
2 Manual go-around
2.1 Safety considerations
2.1.1 Following a loss of the automatic pilot below the DH, it should be safe to execute and perform a manual go-around from any point on the approach down to touchdown, in all configurations to be certified. The manoeuvre should not require exceptional piloting skill, alertness or strength, and should ensure that the aeroplane remains within the obstacle limitation surface specified in ICAO Annex 14 for a precision approach runway Category II or III.
2.1.2 For aircraft for which a go-around from a very low altitude may result in inadvertent runway contact, the safety of the procedure should be established giving consideration to at least the following:
a. Where the guidance information provided by the go-around mode is retained, it should be shown to have safe and acceptable characteristics throughout the manoeuvre.
b. Other systems (e.g. automatic throttle, brakes, spoilers and reverse thrust) should not operate in a way that would adversely affect the safety of the go-around manoeuvre.
2.1.3 Non-normal procedures that are applicable following a loss of a fail-passive automatic landing system (see paragraph 3) may require the flight crew to revert to manual control using primary display information, such as attitude and airspeed, to perform a manual go-around. Where applicable, consideration should be given to failure conditions that could result in a loss of both the automatic landing system and the relevant primary display information.
2.2 Performance
The safety of the go-around manoeuvre may be determined by flight testing (typically 10 go-arounds) supported, where necessary, by simulator testing.
If a loss of the automatic pilot can result in a loss of the flight director guidance, this should be considered during the performance demonstration.
3 Manual landing
Following a loss of the automatic control capability below the DH, a safe landing should be demonstrated in accordance with established procedures.
a. The demonstration should take into account at least the following variables:
i. centre of gravity (CG), ii. landing weight, and iii. wind conditions.
b. If the demonstration is to be performed with a simulator, the simulator should be:
i. equipped with a visual system that provides an acceptable representation of the actual visibility conditions for which operational approval is sought; and ii. suitably validated by flight test demonstrations for the landing manoeuvre.
c. The number of manual landings to be performed should be related to the probability of a loss of the automatic landing system below the DH.
4 Consideration of the effects of engine failure
4.1 Where the landing system provides automatic control of the rudder pedals, a demonstration should be made to show that, for automatic approaches initiated with all engines operating:
a. automatic go-around, and b. automatic landing can be performed safely following the failure of any single engine at any point during the approach down to touchdown without the pilot needing to intervene and assume control.
4.2 The automatic pilot should remain engaged following the failure of any single engine, taking account of the loss of systems (e.g. electrical and hydraulic systems) associated with the failed engine.