Unintentional release of diving helmet – neck dam/helmet securing arrangements

  • Safety Flash
  • Published on 2 August 2016
  • Generated on 24 January 2026
  • IMCA SF 20/16
  • 1 minute read

A Member reported two incidents in which there has been unintentional release between neck ring and helmet on a KM17C diving helmet during saturation diving operations.

What happened?

Members are encouraged to ensure that diving personnel are aware and that they check the interface between helmet and its securing arrangement towards other equipment supporting the diver. Working conditions could also give same results, e.g. working close to (taut) wires or large insertion bolts, etc.

Our member identified the following corrective actions:

  • Verify that interface between helmet and other diving equipment is such that it cannot hook up the release mechanism.
  • Be aware of the potential of release such that operational measures could be taken to prevent this.
  • Report any further problems (with helmet and locking mechanisms) immediately.
Helmet neck dam

Incident details

The manufacturer has developed a pull pin sleeve, which may also work to prevent this from recurring. See the Kirby Morgan website for more details.

Pull pin sleeve kit diagram
Kirby Morgan instruction diagram

A series of photographs follows for illustrative purposes:

Divers equipment

Diver’s equipment interfacing with harness and jump jacket

Kirby Morgan helmet

Kirby Morgan 17C divers helmet with Jewel 601 reclaim hat

Clash between diver helmet pull pin and jump jacket

Clash between diver helmet pull pin and jump jacket

Helmet/neck ring pull pin securing mechanism (L) closed position (R) open position

Helmet/neck ring pull pin securing mechanism (L) closed position (R) open position

Bail out system

Evaluation of the bail-out system – position of helmet/neck ring pull pins in relation to diver’s harness (L) head in normal upright position (R) head bent forward, looking down

Position of helmet/neck ring pull pin

Position of helmet/neck ring pull pin in relation with bailout/jump jacket equipment with head bent forward looking down

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