SUBJECT: NON-SLIP SURFACES ON SHIP HELICOPTER LANDING
SITES
OCCURRENCE SUMMARY:
The Hughes 500 helicopter had been chartered to transfer two
crewmembers and their luggage from shore to the ship "Karoo", a
bulk ore carrier, at anchor near Mackay. After an uneventful
flight, the pilot landed the helicopter on the port side of cargo
hatch number seven. The steel cargo hatch, designated as the ship's
helicopter landing site (HLS), had a smooth painted surface. The
cargo hatch peaked in the centre and sloped down 0.85 degrees to
both port and starboard sides. The pilot positioned the helicopter
so that the tail rotor protruded over the port side edge of the
hatch. In this position, the helicopter was under the influence of
a crosswind from the left front quarter. The pilot reduced the
engine power to idle, friction-locked the cyclic and collective
controls, and locked the anti-torque pedals. He then left the cabin
to supervise the disembarkation of the passengers and remove their
luggage. After the passengers disembarked, the helicopter commenced
to slide slowly downslope towards the edge of the cargo
hatch.
The pilot ran from the right to the left side of the helicopter
and attempted to unlock the anti-torque pedals and climb aboard. As
he did so, the nose of the helicopter lifted when it weathercocked
left into the 25-kt south-easterly wind. The helicopter, with the
pilot partly on board, slid off the hatch and fell 3 m onto the
main deck, landing inverted on raised piping which ran along the
length of the deck. The pilot fell between the hatch and the piping
and was saved from injury by two steel posts supporting the pipe
system.
ANALYSIS:
A factor in this accident was that the ship's HLS did not have a
non-slip surface. When the weight in the helicopter was reduced
following disembarkation of the passengers, the smooth hatch
surface, combined with the helicopter's centre of gravity movement,
resulted in the helicopter slipping on the hatch. The steel hatch
had a smooth, painted surface which was not non-slip. Fortunately,
no injuries resulted from this accident, but the potential for
serious injury or death to personnel was clearly evident.
Factors in ship-helicopter transfers that may increase the risk of
helicopter and personnel slippage include:
(a) operations are conducted in varied weather conditions;
(b) operations are conducted on ships that are under way
(c) sea spray or dew on HLS surfaces reduces the coefficient of
friction of the surface;
(d) ship helicopter landing sites are subject to unpredictable
movement due to the pitch and roll of the ship;
(e) some hatch covers used as a HLS may have significant camber
either fore and aft or athwartships; and
(f) operations are conducted at night.
MARITIME LEGISLATION
Marine regulations recommend the provision of non-slip surfaces
for ship HLSs but do not mandate their provision.
Within the marine environment, the Australian Maritime Safety
Authority - Marine Orders deals with safety issues relating to
helicopter operations on ships operating in Australian territorial
waters.
MARINE ORDERS
Marine Orders, part 57, Issue 2 - Helicopter Operations, makes
provisions for and in relation to:
(a) The protection of the health and the security from injury of
persons engaged in the loading and unloading of ships; and
(b) the safety of persons, including pilots, going on or coming
from, or on board, ships,
in connection with transfer operations by helicopter.
Marine Orders part 57 states that requirements for safe
arrangements for transfer operations by helicopter are regarded to
have been met if arrangements, equipment, instructions and training
comply with:
(a) the Australian Code of Safe Practice for Ship-Helicopter
Transfers, published by AMSA; or
(b) the International Chamber of Shipping Guide to Helicopter/Ship
Operations to the extent that it is not inconsistent with
(a).
AUSTRALIAN CODE OF SAFE PRACTICE FOR SHIP-HELICOPTER
TRANSFERS
The Australian Code of Safe Practice for Ship-Helicopter Transfers
applies to all routine transfers of personnel or goods by
helicopter to or from ships while under way or at anchor. It does
not apply to fixed or floating structures, or vessels employed in
the offshore oil or gas industry.
Section 3 of the code deals with the HLS and states the
following:
"The HLS should have a non-slip surface."
Appendix 1 states the following:
"All paint used within the limit of the clear zone of an HLS or
the manoeuvring zone of an HWA [helicopter winching area] should be
such as to provide a non-skid surface whether wet or dry".
These statements do not clearly affirm that it is mandatory for a
ship HLS to have a non-slip surface. The word "should" indicates a
recommendation for the HLS to have a non-slip surface but does not
mandate it.
INTERNATIONAL CHAMBER OF SHIPPING'S, "GUIDE TO HELICOPTER/SHIP
OPERATIONS"
The International Chamber of Shipping's, "Guide to Helicopter/Ship
Operations", when dealing with the provision of HLS surfaces,
states the following:
"Section 4.5 Areas to be used by the helicopter landing gear or by
personnel should have anti-slip surfaces even when wet".
"Section 4.2.4 The aiming circle (Touch Down Zone) should be
completely covered with a matt anti-slip surface".
This publication is a guide and is not intended to be binding.
Shipping companies, ships' masters and officers, helicopter
operators and aircrew are all responsible for acting in accordance
with relevant national regulations and company instructions.
It therefore does not appear compulsory under marine legislation
for a ship HLS to have a non-slip surface.
MARINE PILOT TRANSFERS EXEMPTION
Section 4 of the Code of Safe Practice provides an exemption from
section 3 for marine pilot transfers and states the
following:
"Helicopter-ship operations solely for the purpose of effecting
the transfer of a marine pilot may be exempted from the provisions
of [Section] 3 subject to the following:
(i) A clear area of deck exists which must be no less than twice
the main rotor diameter and preferably 2D wherever possible.
(ii) The helicopter pilot brings the aircraft to a hover clear of
the ship's side and then hover-taxis to the landing position or the
ship's master and the helicopter pilot agree that the landing may
be safely made in another manner.
(iii) Sea and weather conditions are such that the ship's master
and the helicopter pilot agree that the operation may be carried
out safely and in accordance with flight rules, Civil Aviation
Regulations and the flight operations manual".
Correspondence received from operators conducting helicopter
marine pilot transfers has described situations where the
helicopter has begun to slide whilst on the deck of a vessel during
embarkation and disembarkation of marine pilots. When the
helicopter begins to slide, the only option available is to become
airborne. This situation, particularly at night, puts at risk the
lives of those disembarking or embarking as well as the helicopter
crew and the ship's crew.
Marine pilot transfer operations are no different from other
ship-helicopter transfer operations in that the helicopter lands on
the HLS and transfers a passenger. Marine pilot transfers are
usually performed with the ship under way. The danger to
passengers, the helicopter crew, and the ship's crew is still
present if the helicopter slips on the designated HLS.
Many ship HLSs apparently do not have a non-slip surface. A
non-slip surface on a ship HLS reduces the risk of the helicopter
slipping with the pitch or roll of the ship. Additionally, a
non-slip surface on the ship HLS reduces the risk of injury through
personnel slipping on the deck.
CIVIL AVIATION LEGISLATION
The Civil Aviation Regulations - Orders and Guidelines, does not
deal with the surface texture of a ship HLS. The landing area, size
and requirements are referred to in Civil Aviation Advisory
Publication (CAAP) 92-2 (1) - Guidelines for the establishment and
use of helicopter landing sites (HLS). These guidelines do not
address the provision of a non-slip surface.
SHIP-HELICOPTER TRANSFER OPERATORS
Operators conducting ship-helicopter transfers approve ship-based
HLSs in accordance with their operations manual and guidelines laid
down in CAAP 92-2 (1). No consideration is required to be given by
the operator to the non-slip nature of the helicopter landing site
when approving the site for their operations.
SAFETY DEFICIENCY
Many ship HLSs being used for ship-helicopter transfers are not
equipped with non-slip surfaces. The requirement for a non-slip
surface on ship HLSs is not mandated in marine legislation,
although it is recommended.
Helicopter landing sites used for marine-pilot transfer operations
are exempted from the recommended non-slip surface under certain
conditions.
It is not a requirement for helicopter operators to consider the
non-slip nature of the ship HLS surface when approving or surveying
the HLS for their operations. There is no requirement in operations
manuals for operators to only use a HLS with a non-slip
surface.
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.
IR970173 also refers and was addressed to the Australian Maritime
Safety Authority.
BASI Interim Recommendation 970174 recommends that the Civil
Aviation Safety Authority (CASA) require operators of helicopters
involved in ship/helicopter transfers to include in their
operations manuals the requirement to only use helicopter landing
sites with non-slip surfaces.
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.
Pilot at the Controls
Civil Aviation Order (CAO) 95.7 allows a pilot to leave the
controls of a helicopter if that absence from the cockpit is
essential to the safety of the helicopter or of the persons on, or
in the vicinity of, the helicopter. It does not address the nature
of the surface on which the helicopter may stand when the pilot
leaves the controls, nor does it address other factors conducive to
movement of the helicopter.
This deficiency was recognised by the District Flying Operations
Manager, Townsville, who issued a Direction under Civil Aviation
Regulation (CAR) 215(3) regarding pilots leaving the controls of a
helicopter (copy attached). direction has been circulated to other
Districts with a recommendation for adoption. Further, the issue of
pilots leaving the controls of a helicopter while it is running
will be addressed during the current regulatory review.
HLS Standards
In its Interim Recommendation, BASI has stated that CASA's
Guidelines for the Establishment and Use of Helicopter Landing
Sites (CAAP 91-2(1)) do not address the provision of a non-slip
surface. This statement is not correct. The CAAP addresses two
types of marine HLS: the ship's side HLS and the midship HLS. In
both cases, the surface is addressed with the following
wording:
"The LLA should be entirely within the FATO and be capable of
safely accepting the static and dynamic loads of the operation as
well as have a non-slip surface."
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.
Attachment: Direction to Helicopter Operators
