747-400 Heavy Vibration - should I report it?
As the gear is retracted, the wheels are bough to a halt as you don't want all that rubber rotating at high speed inside the airframe. Main gear uses the aircraft brake system as the gear start to retract and the wheels are stopped before they get in the wells. However, the nose gear doesn't have brakes, so the wheels are still rotating as they enter the bay and are stopped by braking pads in the nose gear bay.
The vibration you felt was the wheels rubbing against the braking pads and this is normal.
The vibration you felt was the wheels rubbing against the braking pads and this is normal.
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When I rotate in my RC 114TC, I will just apply light pressure to the rudder pedals to stop the wheels. Easier on the lift rams as the gyroscopic load is then eliminated. Would be nice if there were priority valves in the sys to port some momentary brake pressure.
Paxing All Over The World
ut As an amateur, my guess is that, since the current system has worked well for 35 years, there is not much liklihood of it being changed by Boeing.
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Why change a good thing, but there again, technology marches on and someone might come up with a better idea.
Most likely the powered nose wheels that they are developing will stop the wheels from rotating.
(Ideas type of people switch me on)
Just finished watching an interesting show on the Discovery channel about RR's facility in Derby regarding their new generation of engines.
Most likely the powered nose wheels that they are developing will stop the wheels from rotating.
(Ideas type of people switch me on)
Just finished watching an interesting show on the Discovery channel about RR's facility in Derby regarding their new generation of engines.
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744 vibration on gear up selection. Shakes the sh
out of everyone and aircraft.
At Q this was a problem early in the intro of this aircraft. Main gear wheels out of round were believed to be the problem and subsequently 100s of wheels were changed until defect persisted with 16 new wheels fitted to one of the aircraft with this recurring defect.
White stripes were painted on the tyres (not tires) and take offs were filmed to see if wheels were spinning as the gear lifted into the wheel bay to identify the time of vibration during gear up selection.
For info. When filmed the wheels don't wind down slowly they came to a complete stop within a couple of frames.
At the same time UA BA were having similar defects.
From memory as this was 10 years + ago
The problem was traced to a bad batch of valves that provide the "inflight braking". From memory this valve is sequenced thru the R/H wing landing gear door. Upon gear up selection the gear doors open and this positions a hyd valve to send a hydraulic "signal to the inflight braking ops valve to apply the ALT brake system to stop the wheels rotating. This vave was shuddering/occilating/worn and was creating the vibration by not applying correct braking pressure allowing wheels to shudder as their rotation is slowed by a on-off-on-off-on-off-on braking.
Now that this problem is known. If it is reported a part replacement is scheduled to fix, Most tech crews have seen it so its no drama either.
Remember you are in good hands
Yes I know I haven't used correct nomenclature or techo words but trying to please all reading this post, and most importantly this thread was started by a helicopter pilot
I was once told that the big blades above the helicopter pilots head were put there to keep the pilot cool.
Because you should see him sweat if they stop
out of everyone and aircraft.At Q this was a problem early in the intro of this aircraft. Main gear wheels out of round were believed to be the problem and subsequently 100s of wheels were changed until defect persisted with 16 new wheels fitted to one of the aircraft with this recurring defect.
White stripes were painted on the tyres (not tires) and take offs were filmed to see if wheels were spinning as the gear lifted into the wheel bay to identify the time of vibration during gear up selection.
For info. When filmed the wheels don't wind down slowly they came to a complete stop within a couple of frames.
At the same time UA BA were having similar defects.
From memory as this was 10 years + ago
The problem was traced to a bad batch of valves that provide the "inflight braking". From memory this valve is sequenced thru the R/H wing landing gear door. Upon gear up selection the gear doors open and this positions a hyd valve to send a hydraulic "signal to the inflight braking ops valve to apply the ALT brake system to stop the wheels rotating. This vave was shuddering/occilating/worn and was creating the vibration by not applying correct braking pressure allowing wheels to shudder as their rotation is slowed by a on-off-on-off-on-off-on braking.
Now that this problem is known. If it is reported a part replacement is scheduled to fix, Most tech crews have seen it so its no drama either.
Remember you are in good hands
Yes I know I haven't used correct nomenclature or techo words but trying to please all reading this post, and most importantly this thread was started by a helicopter pilot
I was once told that the big blades above the helicopter pilots head were put there to keep the pilot cool.
Because you should see him sweat if they stop
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Funny this. I had exactly the same occurence last year out of LHR on the BA015. I went and viewed the flight deck post flight and was reliably informed by the Captain that the reason was the Virgin A340 that went off of 27L before us.
