A320 - pitch trim wheels sound?
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A320 - pitch trim wheels sound?
Hi everybody,
as I'm non-rated, please excuse this question:
Is there a possibillity for the cockpit crew to notice a changing pitch trim value other than looking at the lower ECAM or taking the head down to the wheels?
I know that the 737 has a very distinct rattling sound but I couldn't find any info, if the trim wheels on the bus produce any sound that is loud enough to be noticed on a noisy flightdeck?
Thank you
as I'm non-rated, please excuse this question:
Is there a possibillity for the cockpit crew to notice a changing pitch trim value other than looking at the lower ECAM or taking the head down to the wheels?
I know that the 737 has a very distinct rattling sound but I couldn't find any info, if the trim wheels on the bus produce any sound that is loud enough to be noticed on a noisy flightdeck?
Thank you
The trim wheels on A320, A321, A330 make no discernible noise during flight - at least I have never heard any. Sometimes on taxy in after landing one can hear a faint noise, as the horizontal stabiliser is automatically reset to the neutral position.
The Airbus trim wheels do not move as much as a Boeing's, which from memory, (am not Boeing rated), whiz around quite fast and quite a lot. Airbus trim wheels normally move relatively slowly and not as far; usually between 30 to 100 degrees at a time - I guess the gearing is different?
The Airbus trim wheels command hydraulic motors which actually move the stabiliser screw jacks. Perhaps Boeing's trim wheels move the screw jacks directly and therefore need more gearing? I don't know.
The Airbus trim wheels do not move as much as a Boeing's, which from memory, (am not Boeing rated), whiz around quite fast and quite a lot. Airbus trim wheels normally move relatively slowly and not as far; usually between 30 to 100 degrees at a time - I guess the gearing is different?
The Airbus trim wheels command hydraulic motors which actually move the stabiliser screw jacks. Perhaps Boeing's trim wheels move the screw jacks directly and therefore need more gearing? I don't know.
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Not a runaway stab, but this thread discusses an incident where FCS law reversion led to the autotrim function being stopped, leaving the stabiliser in the fully nose-up trim position. During the subsequent stall recovery the crew did not account for this and ran out of elevator authority as a result, losing control of the aircraft.
Definitely a reminder of how important pitch trim can be.
http://www.pprune.org/tech-log/52784...ml#post8160305
Definitely a reminder of how important pitch trim can be.
http://www.pprune.org/tech-log/52784...ml#post8160305
Originally Posted by Uplinker
Perhaps Boeing's trim wheels move the screw jacks directly and therefore need more gearing? I don't know.
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On the 747 the trim wheel noise was generated by a small piece of photographic film against a toothed wheel -just like the piece of paper we put into the spokes of our bikes when we were children. Typical Boeing solution -cheap and cheerful!
short flights long nights
On the 777 there is no wheel, and no sound...
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Why would anyone need to be reminded?
j
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roulis
The ears hear trim wheel sound not the eyes and if they are OK they will hear the master warning also. ECAM doesn't appear quietly does it? If Asiana pilots were looking inside they would have noticed their speed.
The ears hear trim wheel sound not the eyes and if they are OK they will hear the master warning also. ECAM doesn't appear quietly does it? If Asiana pilots were looking inside they would have noticed their speed.
Boeing did away with noisy trim wheels ages ago, except the geriatric 737...
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Electric trim being a motor that moved the manual trim. The electric trim was controlled by a switch on the control wheel. If that switch malfunctioned, you could have a trim runaway. Since the trim wheel was out of the pilots normal view, he might not notice it until too late.
So, a clicker was added.
