Why does A330 with emergency config will enter direct law after L/G gravity extension
Joined: Aug 2005
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From: ME
can8 ko
Correction. The pitch before flare is +4 degrees from there it goes down to -2 degrees so total pitch down is 6 degrees and not 8 degrees as I said. A330 has two flare modes when out of normal law. In ALT1 it has flare mode in which roll is normal only pitch is direct stick to elevator and when in ALT 2 it is like A320, landing gear down direct law. In dual RA fail, inability to read radio altitude is the only problem so it uses the ALT1 flare mode. When in ELEC EMER since there are many inop systems that is not possible. So it reverts to complete gear down direct law. In both these cases the nose down pitch comes from speed reduction and the thrust reduction during flare. The FCS does not apply any nose down elevator.
Correction. The pitch before flare is +4 degrees from there it goes down to -2 degrees so total pitch down is 6 degrees and not 8 degrees as I said. A330 has two flare modes when out of normal law. In ALT1 it has flare mode in which roll is normal only pitch is direct stick to elevator and when in ALT 2 it is like A320, landing gear down direct law. In dual RA fail, inability to read radio altitude is the only problem so it uses the ALT1 flare mode. When in ELEC EMER since there are many inop systems that is not possible. So it reverts to complete gear down direct law. In both these cases the nose down pitch comes from speed reduction and the thrust reduction during flare. The FCS does not apply any nose down elevator.
Last edited by Romasik; 23rd February 2017 at 18:53.
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From: Middle East
Does the computer in A330 do pitch down during flare mode in normal law?
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From: lagos
Been flying the 330 for sometime now and you can barely feel this pitch down effect.
@Romasik, point taken in knowing all of this wont help with the hand flying but a good background on the failure would certainly help in the overall decision making process.
@Romasik, point taken in knowing all of this wont help with the hand flying but a good background on the failure would certainly help in the overall decision making process.
Joined: Aug 2007
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From: Middle East
Hi vilas,
I thought the "pitch down" is a special feature in A320 family only and not for the other widebodies (A330&A340....)....
I am sure the "Pitch down" isnot on A340 but I will read the FCOM for the A330.
Many thanks
I thought the "pitch down" is a special feature in A320 family only and not for the other widebodies (A330&A340....)....
I am sure the "Pitch down" isnot on A340 but I will read the FCOM for the A330.
Many thanks
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From: London
can8
I remember reading in one airbus instructor meeting report that A330 is not a big A320. So I think it will be better to forget A320 during transition. A330 has better redundancy the flare mode and also the AP is available in some situations in alternate law. But in A320 the transition to direct law with gear down is in fact the only flare mode of alternate law. The flare mode of A330 is slight pitch down elevator is applied while in A320 it progressively pitches down by eight degrees. But without Radio altitude measurement there can be no flare mode any way so with gear down it goes in direct law. A330 also does the same in ELEC EMER. That is why you use manual pitch trim. Do not confuse this with A320 Neo not going to direct law with only some failures like double yaw damper fail. Actually it does not even go into alternate law but remains in normal law with flare mode. Airbus wants pilots to carefully handle since there is a failure so only the indication of alternate law is displayed. As I said if you keep comparing A320 you will add to your confusion.
I remember reading in one airbus instructor meeting report that A330 is not a big A320. So I think it will be better to forget A320 during transition. A330 has better redundancy the flare mode and also the AP is available in some situations in alternate law. But in A320 the transition to direct law with gear down is in fact the only flare mode of alternate law. The flare mode of A330 is slight pitch down elevator is applied while in A320 it progressively pitches down by eight degrees. But without Radio altitude measurement there can be no flare mode any way so with gear down it goes in direct law. A330 also does the same in ELEC EMER. That is why you use manual pitch trim. Do not confuse this with A320 Neo not going to direct law with only some failures like double yaw damper fail. Actually it does not even go into alternate law but remains in normal law with flare mode. Airbus wants pilots to carefully handle since there is a failure so only the indication of alternate law is displayed. As I said if you keep comparing A320 you will add to your confusion.
I had a look in my manuals and don't see any differences?
Cheers
Joined: Mar 2001
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From: I wouldn't know.
The sharklet aircraft do not go into direct law with gear down. They stay in "alternate" law which is actually normal law in this case. Compare the FCOM side by side for a non sharklet and a sharklet aircraft, FCOM-PRO-ABN-22-AUTO FLT YAW DAMPER SYS. The sharklet aircraft omit the line WHEN L/G DN: DIRECT LAW.
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From: Wanderlust
Pilot James
The sharklet aircraft has better maneuverability so it retains normal law with yaw damper 1+2 and two other failures while normal A320 would go in alternate law and gear down direct law. But since There is a failure Airbus wants pilots to be careful so only indications of alternate law are shown but aircraft is in normal law and normal flare mode is available. This one is also of the many replies I obtained from Airbus.
The sharklet aircraft has better maneuverability so it retains normal law with yaw damper 1+2 and two other failures while normal A320 would go in alternate law and gear down direct law. But since There is a failure Airbus wants pilots to be careful so only indications of alternate law are shown but aircraft is in normal law and normal flare mode is available. This one is also of the many replies I obtained from Airbus.
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From: Gone Flying...
When in EMER ELEC CONF, on the A330, the LANDING GEAR must be extended by GRAVITY (and Nose Wheel Steering is LOST in all cases) in order to avoid strong fluctuation of the G HYD pressure, which may cause spurious disconnection of the EMER GEN, when it is powered by EDP.
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From: Gone Flying...
The reason why the aircraft enters Direct Law when LNDG GEAR down by Gravity is because of the need for using of LAND RECOVERY (to energize ILS 1, SFCC 1, LGCIU 1, BSCU 1, and WHC 1). This, will disconnect the EMERG GEN and will put electricity on BATs only.
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From: FL390
.The sharklet aircraft has better maneuverability so it retains normal law with yaw damper 1+2 and two other failures while normal A320 would go in alternate law and gear down direct law.
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From: Al tube.
I understand all A321 aircraft, including early versions, also did not have the problem of reverting to direct law on gravity gear extension due to the extended nose gear not disturbing the airflow around the RAT and thus the RAT keeps running. I don't know if this is the case with early A318/319s?
Thread Starter
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From: Taipei 101
Hello guys
Kinds of busy last week! Very appreciate so many back and forth Q & A. I could see not only me but also other one could learn something from this discussion! It's more than my expectation!
Kinds of busy last week! Very appreciate so many back and forth Q & A. I could see not only me but also other one could learn something from this discussion! It's more than my expectation!
