What is the minimum number of watertight compartments required for the hull and auxiliary floats of a water-based or amphibian rotorcraft?

The section does not specify a minimum number of compartments; it only requires enough watertight compartments so that, with any single compartment flooded, the buoyancy provides a positive water stability margin sufficient to minimise capsizing probability.

Is the buoyancy of wheel tyres always included in the flooded-compartment stability calculation?

No, wheel tyres are included only if used.

What does 'positive water stability' mean in the context of CS 29.755?

It means the buoyancy provides a margin of stability that is positive (i.e., the rotorcraft tends to return to an upright position) and great enough to minimise the probability of capsizing under the worst wave and wind conditions for which approval is desired.

CS 29.755 Hull buoyancy

Q: Does CS 29.755 require that the rotorcraft remain completely upright after a single compartment is flooded?

No, it only requires a margin of positive water stability great enough to minimise the probability of capsizing; it does not require remaining upright.

Q: When a single compartment of the hull or auxiliary floats is flooded, what additional buoyancy sources must be considered in the stability calculation?

The buoyancy of the hull and auxiliary floats, and wheel tyres if used, must be considered.

Q: What is the required margin of positive water stability after flooding a single compartment?

The margin must be great enough to minimise the probability of capsizing the rotorcraft for the worst combination of wave heights and surface winds for which approval is desired.

Q: Which rotorcraft categories are covered by CS 29.755?

Water-based and amphibian rotorcraft.

Q: In the buoyancy assessment, what environmental conditions must be considered for the worst-case scenario?

The worst combination of wave heights and surface winds for which approval is desired.

Q: Are auxiliary floats required to have watertight compartments if they are used?

Yes, if auxiliary floats are used, they must have enough watertight compartments so that with any single compartment of the hull or auxiliary floats flooded, the buoyancy requirement is met.

Q: What is the purpose of the watertight compartments in the hull and auxiliary floats?

To ensure that with any single compartment flooded, the buoyancy of the hull, auxiliary floats, and wheel tyres if used, provides a margin of positive water stability great enough to minimise the probability of capsizing.

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CS 29.755 Hull buoyancy

ED Decision 2003/16/RM

Water-based and amphibian rotorcraft. The hull and auxiliary floats, if used, must have enough watertight compartments so that, with any single compartment of the hull or auxiliary floats flooded, the buoyancy of the hull and auxiliary floats, and wheel tyres if used, provides a margin of positive water stability great enough to minimise the probability of capsizing the rotorcraft for the worst combination of wave heights and surface winds for which approval is desired.

Details

Source-Title: CS 29.755 Hull buoyancy View latest amendments

Erulesid: ERULES-1963177438-5421 Compare versions

Domain: Initial airworthiness

Amendedby: Initial issue

Applicabilitydate: 14 November, 2003

Entryintoforcedate: 14 November, 2003

Regulatorysource: ED Decision 2003/16/RM Navigate

Regulatorysubject: CS-29

Typeofcontent: CS (Certification specification)

Origin: EASA

Category: EAR