The MV " Karoo ", a large bulk carrier, was at anchor 11 km off Mackay, facing approximately 090 degrees M. The wind was from the south-east at about 25 kts. The helicopter had been chartered to transfer two members of the vessel's crew from shore to the ship. After an uneventful flight, the pilot landed the helicopter on the port side of cargo hatch number seven which measured 20.0 m by 14.45 m and had a smooth painted steel surface. The cargo hatch peaked in the centre and sloped down 0.85 degrees to both the port and starboard sides of the ship. The pilot positioned the helicopter so that the tail rotor protruded over the edge of the hatch on the port side. In this position, the helicopter was under the influence of a crosswind from the left front quarter. The pilot stated that he reduced the engine power to ground idle, friction-locked the cyclic and collective controls, and locked the anti-torque pedals. He then exited the cabin and walked to the right side of the helicopter to supervise the disembarkation of the passengers and to remove their luggage.
After the passengers had stepped from the helicopter, it weather-cocked about 30 degrees to the left and commenced to slide slowly backwards towards the edge of the cargo hatch. The pilot ran back to the left side of the helicopter and attempted to unlock the anti-torque pedals prior to climbing aboard. The front of the helicopter then pitched up with the pilot partly on board, then fell 3 m onto the main deck and landed inverted beside raised piping which ran along the length of the deck. The pilot fell between the hatch and the piping and was saved from flailing rotor blades by two steel posts supporting the pipe system. The engine continued to operate for 30 to 60 seconds after the impact.
In accordance with standard procedures, the vessel's fire-fighting crew was on duty for the arrival of the helicopter. The crew sprayed the wreckage with foam and salt water as a precaution against fire.
Examination at the accident site revealed scratch marks that indicated that the left skid landing gear had dug into the painted hatch surface. The rear portion of the left skid broke in overload as the helicopter pitched up. Examination of the wreckage confirmed that the pilot had locked the controls and that the throttle control was positioned in the ground-idle detent.
An Australian Maritime Safety Authority (AMSA) booklet "Ship - Helicopter Transfers, Australian Code of Safe Practice", states that the helicopter landing site (HLS) should have a non-slip surface. On the MV "Karoo", the cargo hatch designated as the HLS was painted, smooth steel plate. It did not have a non-slip surface.
Civil Aviation Orders (CAO) generally required that the pilot remain at the controls during engine operation. However, CAO 95.7.7 allowed an exemption if the pilot considered that passenger safety, or the safety of people in the vicinity, may be compromised, provided that the controls were locked and the pilot remained in the immediate vicinity. The pilot in this instance regarded the passengers as potentially at risk due to their unfamiliarity with the helicopter operations and their inability to understand English. As an additional safety consideration, he had positioned the tail rotor beyond the edge of the cargo hatch.
The crosswind landing technique required the pilot to counter the total effect of wind on the helicopter by positioning the cyclic control so that the main rotor thrust was biased into wind, towards the 10-o'clock position, to counteract the aerodynamic drag. When the pilot locked the controls, the cyclic control was locked in the position that was selected for landing, maintaining the main rotor bias.
When the helicopter weathercocked through 30 degrees, probably as a result of the weight reduction when the passengers and their baggage were removed, the main rotor was no longer biased into wind but produced both a vertical and horizontal lift component. This allowed the helicopter to slide rearwards and pitch up. As the left skid dug into the hatch surface, possibly due to the pilot's weight on the left side, the helicopter commenced a dynamic roll-over and fell off the hatch cover onto the deck.
Had the pilot remained in the cabin, he would have been able to manipulate the controls to prevent movement of the helicopter.
- The pilot did not remain at the controls of the helicopter.
- The helicopter was parked crosswind.
- The helicopter landing site did not have a non-slip surface.
During the course of the investigation, the Bureau of Air Safety Investigation issued two Interim Recommendations (IRs). These recommendations are reproduced below. Pertinent comments in response to the recommendations and the Bureau's classification of each response are also included.
"IR970173 (issued 6 February 1998)
The Bureau of Air Safety Investigation recommends that the Australian Maritime Safety Authority:
- make it mandatory for all ship helicopter landing sites to have a non-slip surface;
- make changes to the publication "Ship - Helicopter Transfers, Australian Code of Safe Practice" to clearly reflect this requirement; and
- check compliance with this requirement during ship inspections."
AMSA response 1, in part, stated:
"Thank you for your letter of 6 February 1998, advising of the Bureau's interim recommendation IR970173.
AMSA is fully committed to ensuring safe procedures in all areas of maritime operations and for this reason will endeavour to implement your interim recommendation to the maximum extent possible taking into account practical considerations. Comments on specific areas of the recommendation are as follows.
- make it mandatory for all ship helicopter landing sites to have a non slip surface
Marine Orders Part 57 (Helicopter operations) makes it mandatory for the master of a ship not to permit the transfer of persons and goods between helicopter and ship unless certain arrangements, equipment, instructions and training have been provided. The Marine Orders further amplify this requirement by stating that arrangements, equipment, instructions and training that comply with the Australian Code of Safe Practice for Ship-Helicopter Transfers or the International Chamber of Shipping Guide to Helicopter/Ship Operations will be regarded as meeting the requirements. The Code and Guide both state that helicopter landing sites should have a non slip surface.
- make changes to the publication "Ship - Helicopter Transfers, Australian Code of Safe Practice" to clearly reflect this requirement
Maritime legislation is moving away from prescriptive type requirements towards more responsibility being placed upon the operator to conduct operations safely within a safety regulatory framework. The framework provides the operator with guidance on how to comply with safety requirements but does not rule out other appropriate measures that provide the same level of safety. This of course places a heavy duty of responsibility on the operator to be able to demonstrate that any departure from the guidelines provides at least the same level of safety as if the guidelines were fully complied with. For this reason AMSA would be reluctant to change the present Code of Safe Practice to make it more prescriptive.
- check compliance with this requirement during ship inspections
Unfortunately for a number of reasons this recommendation is not practical. For any ships using helicopter transfer for pilot boarding the inspection would be after the fact and would not assist in ensuring compliance. The majority of ships do not have dedicated HLS's and masters can state that they do not normally undertake helicopter operations and if they intended to do so would then prepare the landing site accordingly.
Regardless of the foregoing comments AMSA believes that the reports received by BASI and our own intelligence suggests that there may be a concern in the area of safe ship/helicopter operations and the full compliance with safe operating practices by those involved. In order to comply with the spirit of your recommendation and in order to address the possible non compliance by operators with the Code of Safe Practice AMSA intends to take the following action.
A Marine Notice will be issued advising masters, owners, agents and marine pilots of the specific occurrence and other reported incidents associated with the lack of a non slip surface on shipboard helicopter landing sites. The notice will advise that the provision of a non slip surface for helicopter landing sites is considered to be of paramount importance in ensuring the safety of ship/helicopter operations and that all ships will be expected to take appropriate action to ensure that a non slip surface is provided for the helicopter landing site prior to allowing such operations to be conducted.
Agents for ships proceeding to Australia will be requested to bring this notice to the attention of masters prior to arrival at the first Australian port and marine pilot providers will be advised that AMSA expects them to advise ship masters of this requirement in their initial contact with the ship. A copy of the Marine Notice will be forwarded to BASI as soon as it is promulgated. A copy of Marine Orders Part 57 together with the Australian Code of Safe Practice for Ship-Helicopter Transfers will be forwarded to the publishers of "Guide to Port Entry" which is an international publication widely used by a majority of the world's shipping. I trust that these measures, together with the present regulations, satisfy the requirements of the interim recommendation".
AMSA response 2 stated:
"On 31 March 1998 we wrote to you regarding action to be taken by AMSA following BASI interim recommendation IR970173.
As advised, this Authority has issued a Marine Notice advising masters, ship owners, agents and marine pilots of the importance of providing a non-slip surface on HLS's and of the occurrence of the relevant accident and other similar reported incidents".
Response classification: CLOSED - ACCEPTED
"IR970174 (issued 6 February 1998)
The Bureau of Air Safety Investigation recommends that the Civil Aviation Safety Authority require helicopter operators involved in ship-helicopter transfers to include in their operations manual the requirement to only use helicopter landing sites with non-slip surfaces."
CASA response, in part, stated:
"The recommendation is based on a number of factors related to the accident of Hughes 369 helicopter VH-WHP on board a ship on 17 July 1997. The BASI analysis of the accident appears to lead to the assumption that the major cause of the accident was the lack of a non-slip surface on the shipboard helicopter landing site. CASA agrees that the lack of a non-slip surface was a factor in the accident but contends that the major factor was the absence of the pilot from the controls in circumstances conducive to slippage of the helicopter on the ship's deck.
CASA does not agree that helicopter operations should be prohibited from landing at marine landing sites without non-slip surfaces when, in the opinion of the pilot, such operations can be conducted in safety. CASA considers that the guidance contained in CAAP 91-2(1) and in the Australian Code of Safe Practice for Ship-Helicopter Transfers relating to non-slip surfaces is adequate for normal operations.
Accordingly, CASA does not intend to restrict the operations of helicopters involved in marine transfers but will instead focus attention on factors to be considered before a pilot leaves the controls of a helicopter while it is running".
Response classification: OPEN
Local safety action
The operator of the helicopter has since amended the Company Operations Manual to take into account the lessons learnt from this accident. Company pilots are now required to remain at the controls of the helicopter while the engine is operating. If passenger considerations require, an attendant will be carried to assist with embarkation and disembarkation.
|Date:||17 July 1997||Investigation status:||Completed|
|Time:||1635 hours EST|
|Location:||11 km E Mackay, Aero|
|Release date:||01 February 1999||Occurrence category:||Accident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Hughes Helicopters|
|Type of operation||Charter|
|Damage to aircraft||Substantial|
|Departure point||Mackay, QLD|
|Departure time||1620 hours EST|
|Destination||MV "Karoo", 11 km E Mackay, QLD|
|Role||Class of licence||Hours on type||Hours total|