Aircraft Zero Stress
 

What is actually Aircraft Zero Stress ?
I think that no stress acting on aircraft is kind of impossible
​​​​​​Is there really such thing as aircraft zero stress ?

In what context are you asking? For example, when it comes to G-force on aircraft structures the stress can go from positive in nature, to neutral (zero), and to negative in nature. In general, most aircraft require some minimal positive force/stress to keep all the systems functioning properly unless it is specifically certified to do otherwise.

Maybe zero stress in term of jacking the aircraft for major structure repair ?

I've never heard the term "zero stress" used before in an aviation context. In most structural repairs there may be instructions to relieve static loads or remove items to ensure proper fastener alignment, etc. but not zero stress. So without an actual example of its use can't offer much more.

You are correct. In aircraft maintenance, term "zero stress" is used when a/c is shored to reduce stresses in the repair area to a minimum.

CAMO and Technical Services
 

Hi guys,
nowday all the tasks related to continuing airworthiness was oversee by CAMO
Do we still need Technical Services ?
is technical service the same thing as CAMO ?
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Zero stresses are specific to jacking during major structural repair or modifications. The OEM provided the load data specific to each jack point which need to be monitored very closely.

It depends on the organization. In MROs tech services are under 145. But in airlines, they are part of CAMO.

"Zero stress" term means that aircraft in maintenance is supported in a way that certain part of structure is not loaded-stressed or, better, is stressed to a minimum, that allows for removal of significant part of structure without disturbing the shape of structure by doing that.
At my place this is regularly done for example for replacement of entire skin panels (of several square metres size) or opening the riveted seam between wing skin and wing spars to rectify corrosion etc. It is a critical job, as doing it wrong might warp the structure and make impossible to install / put it back together!!! A/C is supported in several places with special jacks with load cells of course and loads are strictly monitored/kept to make sure warping does not happen.
Therefore, A/C under zero stress is well marked and has strict limitations on how many (if at all) persons can walk on the aircraft. Hope that clarifies it.