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Old 24th December 2019 | 14:19
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ApolloHeli
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: ATPL
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Originally Posted by jellycopter
The AIC relating to Servo Transparency (Jack Stall) quotes Airbus stating that 'Density Altitude' effects the likelihood of encountering the phenomenon. The CAA AIC goes further and states 'high density altitude' indicating that the risk is greater, the higher the aircraft.

If the air is less dense as altitude increases, how can Servo Transparency (caused by aerodynamic control loads) be more likely? Discuss.

JJ
Nothing but an educated assumption here; as density decreases, blade pitch will need to be increased to maintain a given flight condition (say 100kt cruise) so for a causal manoeuvre (usually a sharpish turn or pitch up), the severity of the manoeuvre needn't be as high to produce the same flight control loads as the collective pitch setting is already higher.
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