Can a 146 pilot answer this please?
Thread Starter
Join Date: Oct 1999
Location: UK
Posts: 3,325
Likes: 0
Received 0 Likes
on
0 Posts
Can a 146 pilot answer this please?
There is an Avro RJX on display at Manchester Airport Viewing park. It has suffered elevator damage through being parked tail-to-prevailing-wind for many years, the servo tab-driven elevators whacking up and down and hitting the rudder (causing a mass balance weight to shear off!).
The aeroplane is now receiving some much needed TLC and the guys wonder if there was any cockpit-operated elevator lock to prevent such damage when the aeroplane was left parked for extended periods. Or was a cherry-picker needed to get up there and put in external locks?
The aeroplane is now receiving some much needed TLC and the guys wonder if there was any cockpit-operated elevator lock to prevent such damage when the aeroplane was left parked for extended periods. Or was a cherry-picker needed to get up there and put in external locks?
Gender Faculty Specialist
IIRC there is a physical lock in the flight deck which is really only to stop the control column flapping around. I don't remember how they worked but there are gust dampers actually in the elevator but the whole things still moves around in the wind (assuming the RJX has the same system, although I did do the RJX type rating ground school bit it was a long time ago).
Not much you can do short of sticking some rubber stoppers in.
Not much you can do short of sticking some rubber stoppers in.
The control column is only linked to the servo tabs. Therefore the flight deck control lock only keeps the servo tabs in place but the elevators are free to move (you will sometimes see the elevators move in different directions when parked in a tail wind). It would need some kind of external lock to keep the elevators locked.
The 146 / RJ has a control ‘restraint’. This consists of a spring loaded ball bearing on the end of a free swinging lever which engaged in a U shaped bracket on the control column; holding the stick in a fix position. The concept was that the restraint was sufficient to hold any force feedback from the servo tab, and thus provide some aerodynamic elevator restraint. The RJX had the same system.
The system could be quickly disengaged by pulling the control column; it also provided a fail safe function if the restraint was inadvertently left in during take off - just pull back to rotate as normal - slightly higher force - ball bearing pops out, lever swings clear.
There was a self contained hydraulic gust damper on each elevator; this controlled rate of movement opposed to a fixed position.
The damage describe at #1 suggests that the damper had not been serviced; a low pressure charge would be ineffective in controlling a hard contact on the elevator stop on the tailplane.
The only direct linkage was between the control column and the servo tab (as #4), but if the tab reached its ‘stop’ on the elevator, then with increased stick force the elevator could be moved - but only by very strong pilots in a tailwind.
The system could be quickly disengaged by pulling the control column; it also provided a fail safe function if the restraint was inadvertently left in during take off - just pull back to rotate as normal - slightly higher force - ball bearing pops out, lever swings clear.
There was a self contained hydraulic gust damper on each elevator; this controlled rate of movement opposed to a fixed position.
The damage describe at #1 suggests that the damper had not been serviced; a low pressure charge would be ineffective in controlling a hard contact on the elevator stop on the tailplane.
The only direct linkage was between the control column and the servo tab (as #4), but if the tab reached its ‘stop’ on the elevator, then with increased stick force the elevator could be moved - but only by very strong pilots in a tailwind.
