Recommendation R20030221

Recommendation issued to: Civil Aviation Safety Authority

Recommendation details
Output No: R20030221
Date issued: 16 December 2003
Safety action status:
Background: Why this Recommendation was developed

Output text

Safety Recommendation

The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority consider advising Australian helicopter operators, involved in water-bombing in support of fire fighting operations, of the need to review the type of fire-buckets used to ensure that they comply with the bucket manufacturer's guidance for use on helicopter types and to ensure that they are appropriately maintained.

Initial response
Date issued: 06 February 2004
Response from: Civil Aviation Safety Authority
Action status: Monitor
Response text:

The following response was received from the Civil Aviation Safety Authority on 6 February 2004:

In response to the Bureau's recommendation, CASA is currently preparing a letter to helicopter operators in which the following issues will be highlighted:

* Ensure the bucket is compatible with the helicopter for which it is to be used;
* Ensure compatibility of the ring or the device to connect the hook and the bucket;
* Ensure the operators maintenance program encapsulates the bucket and it's supporting equipment; and
* Remind operators of their obligation to ensure that any aircraft component fitted from time to time to the aircraft is also maintained correctly in accordance with Civil Aviation Regulations (CAR) 39 and 41.

CASA will seek comment on the content of the letter from major operators, including CHC, prior to its distribution.

Further correspondence
Date issued: 11 September 2007
Response from: Civil Aviation Safety Authority
Response status: Closed
Response text:

CASA issued a letter (see below) to operators on 4 August 2004. With the impending fire season, CASA sees a benefit in re-issuing the letter and is arranging for it to be updated and sent.

Notwithstanding that the ATSB was apparently advised in 2004 that the Flight Safety Australia article did not cover the action item in R20030221, CASA believes the article does actually cover the issues raised.

ATSB Note:

The Flight Safety Australia article, CASA issues safety advice for helicopter firefighting referred to in the CASA response text is available on page 10 of the July-August 2004 issue of the magazine and can be found at

The text of the CASA letter referred to is included below:

Subject: Rotorcraft In Fire Suppression Operations Using Underslung Equipment.

Dear Sir or Madam,

Using rotorcraft in aerial application operations, including fighting bush fires using a fabric "bucket" or similar equipment suspended from the cargo hook has become common practice.

In response to the ATSB investigation into a recent near-fatal accident involving helicopter fire bombing operations using an underslung bucket, and with regard to the forthcoming fire-fighting season, CASA takes this opportunity to make the following recommendations to all rotorcraft operators who engage in similar aerial application operations.

Ensure that:

  1. The bucket is compatible with the helicopter with which it will be used. Bucket manufacturers should provide guidance with regard to the range of rotorcraft suitable for use with a particular model bucket. Ensure the applicable model bucket is deployed with the recommended helicopter type and model, and that the recommended bucket and helicopter combination is maintained throughout operations.
  2. The cargo hook is appropriately maintained. CIVIL AVIATION REGULATIONS 1988, REG 39 (1) applicable to Class A helicopters, and CAR 41 (2) applicable to Class B helicopters, require that either a System of Maintenance or a maintenance schedule include provision for carrying out maintenance to all aircraft components from time to time included in, or fitted to, the helicopter. This includes the cargo hook. Operators therefore should have procedures in place to ensure the cargo hook assembly, plugs, wiring and the attaching structure is inspected at appropriate intervals while fitted to the helicopter.
  3. The hook release mechanism is fully operational. The hook release systems, both manual, and electrical, should be functionally tested before commencing operations each day, and each time the hook assembly is fitted to a helicopter. The hook should be electrically "armed" during all sling operations, ready for quick release in an emergency.
  4. The ring or device used to connect the bucket or load to the hook is compatible with the hook. A review of accidents involving loads slung from the hook, reveals that the use of the incorrect size and shape of the ring that links any load attached to the hook could have potentially disastrous results. Problems include an unintended release, (dynamic roll-out) where the strop or ring collapses the hook "keeper" or "mouse" and the load detaches from a closed hook. Another problem encountered has been the load not releasing when intended, even though the hook opens, due to the ring jamming on the hook assembly.

CASA strongly recommends that all appropriate actions be completed, and the necessary procedures put in place before fire fighting operations commence to ensure that this service, so greatly appreciated by the community, is conducted safely.

Last update 03 April 2012