Placards: "No Push"
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Placards: "No Push"
A number of surfaces, mostly control surfaces but sometimes struts, are placarded with the words 'NO PUSH'
Does this mean:
A - do not use this surface as a 'push' point of contact when manoeuvring the aircraft on the ground by people power. Say, pushing the aircraft into a hangar.
B - do not manipulate the surface, during the course of a pre-flight etc, for purposes of checking function.
I've always taken it to be the former option (A), but see a growing number of people interpreting it as 'B'. Since the average POH doesn't seem to specify, which is correct?
Please offer references as able, rather than just state hand-me-down information gained from Instructors / other Pilots
Thanks
Does this mean:
A - do not use this surface as a 'push' point of contact when manoeuvring the aircraft on the ground by people power. Say, pushing the aircraft into a hangar.
B - do not manipulate the surface, during the course of a pre-flight etc, for purposes of checking function.
I've always taken it to be the former option (A), but see a growing number of people interpreting it as 'B'. Since the average POH doesn't seem to specify, which is correct?
Please offer references as able, rather than just state hand-me-down information gained from Instructors / other Pilots
Thanks
i have always used this as in 'A',
In that I always taught my students, and I still do it as a matter of course, move the elevators fully up and down - e.g. in the Cessna types, to check that the elevators actually move all the way to the stops - both 'up' and 'down' stops, and then to check the stops themselves and the lockwires for security etc.
The rudder is sometimes marked 'no push', however I have always believed it to be just that - don't even think of pushing the aircraft using this....
However, once again I do 'move' the rudder to check travel etc, and then to check the 'stops' and lockwires for the above reasons.
Similarly, when checking the ailerons, move fully up and down to ensure that you have full travel, that the small 'locking pins' are in place at the ends of the hinges...and don't forget to firmly hang on to the aileron while you have your fingers on either the end hinge pins or the mass balances to check their security....otherwise...a gust of wind can....hurt.
Then on the Chipmunk for example, the 'fillet' or fairing that runs onto the Vertical Fin from the top of the rear fuselage is HOLLOW, thin aluminium, is ALWAYS marked 'NO PUSH HERE', BUT....because it just seems 'convenient, a lot of people (Silly Ignorant people..) DO!
Despite the fact that the leading edge of the vertical FIN is just as 'handy' and is strong enough to do so.....and is often marked 'Push Here'.....
Sorry, can't give you a POH reference, as I don't have one 'to hand'....
Hope this helps.
Cheers
In that I always taught my students, and I still do it as a matter of course, move the elevators fully up and down - e.g. in the Cessna types, to check that the elevators actually move all the way to the stops - both 'up' and 'down' stops, and then to check the stops themselves and the lockwires for security etc.
The rudder is sometimes marked 'no push', however I have always believed it to be just that - don't even think of pushing the aircraft using this....
However, once again I do 'move' the rudder to check travel etc, and then to check the 'stops' and lockwires for the above reasons.
Similarly, when checking the ailerons, move fully up and down to ensure that you have full travel, that the small 'locking pins' are in place at the ends of the hinges...and don't forget to firmly hang on to the aileron while you have your fingers on either the end hinge pins or the mass balances to check their security....otherwise...a gust of wind can....hurt.
Then on the Chipmunk for example, the 'fillet' or fairing that runs onto the Vertical Fin from the top of the rear fuselage is HOLLOW, thin aluminium, is ALWAYS marked 'NO PUSH HERE', BUT....because it just seems 'convenient, a lot of people (Silly Ignorant people..) DO!
Despite the fact that the leading edge of the vertical FIN is just as 'handy' and is strong enough to do so.....and is often marked 'Push Here'.....
Sorry, can't give you a POH reference, as I don't have one 'to hand'....
Hope this helps.
Cheers
Moderator
A...if the control surface can't handle a person wiggling it about by hand how is it going to handle the forces in flight? If you can check for full and free movement by moving the controls around then surely you can do it by hand from the outside?
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Depends on the context.
A control surface like the rudder says no push rather correctly if your pushing on the back of it to move the aircraft. Its not designed for that.
Gently moving it to check the control surface travel however is a force it is designed for.
Pushing on a hollow aluminium wing strut on a LSA, you might bend the strut or tear the thing off.
A control surface like the rudder says no push rather correctly if your pushing on the back of it to move the aircraft. Its not designed for that.
Gently moving it to check the control surface travel however is a force it is designed for.
Pushing on a hollow aluminium wing strut on a LSA, you might bend the strut or tear the thing off.
Usually all control surfaces operated by mechanical means (cables push rods etc) such as is found in most aircraft other than large power assisted airframes are based on what is called a closed loop system. Basically that means the control surface can be operated from either end of that closed loop, IE the control column or the control surface itself.
'No Push' means just that, doesn't apply to a control surface as you could actually 'pull' a control surface to one side so 'no push' is irrelevant here:-)
Wmk2
'No Push' means just that, doesn't apply to a control surface as you could actually 'pull' a control surface to one side so 'no push' is irrelevant here:-)
Wmk2
'NO PUSH'
When I grew up 'NO PUSH' meant exactly that 'NO PUSH'. You don't "PUSH" on that part of the airframe.
Similar to "NO STAND" or "DO NOT LIFT FROM THIS POINT"
Not "wriggle", not "move up" or "move down" but 'NO PUSH'
I think it was Uncle Roger Bacon who once observed: "It all started with NO STEP."
It's probably opportune to remember that "decal" is an abbreviation for "decalcomania".
Rgds
It's probably opportune to remember that "decal" is an abbreviation for "decalcomania".
Rgds
Sounds like a job for a room full of QCs
We've got some lawyer stuff going on at the moment, and he charges $43.50 per phone call. It's all very neatly itemised on the bill.
It's probably opportune to remember that "decal" is an abbreviation for "decalcomania".
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No Push
Really folks, it is pretty simple. If the surface, whether it be a flight control or a fairing etc, has an advisory such as NO PUSH - DONT PUSH - NO STEP etc it means what it says. Don't push on it, sit on it or step on it. There is a subtle difference in lifting an elevator up and down, moving a rudder left or right, moving an aileron up or down compared to exerting excessive force on them. A bit of good old fashioned common sense should be enough to tell what to do, or not do.
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