Technical guide to the equipment, systems, and infrastructure required for safe helicopter operations on maritime vessels
Night helicopter operations on yachts are significantly more dangerous than daytime operations. The pilot loses visual references (horizon, sea surface, obstacles) and must rely on instruments and the helideck lighting system.
ICAO Annex 14 Vol II and CAP 437 specify lighting requirements for ship-based helidecks:
Glide Path Indicator (GPI) / Helicopter Approach Path Indicator (HAPI): A GPI/HAPI is an optical system that provides the pilot with visual guidance on the correct approach angle (typically 6° for helicopters). The system uses coloured lights: typically red (too low), green (on glide path), yellow/amber (too high). Different systems use different colour combinations.
CAP 437 specifies that a Visual Approach Slope Indicator (VASI) or equivalent should be provided for offshore helidecks. The HAPI is the most common type.
On yachts: GPI/HAPI systems are rarely installed but should be considered essential for any helideck that will be used for night operations or operations in reduced visibility. The cost of a HAPI system is trivial compared to the cost of the helicopter, yet many yacht helidecks worth millions of dollars do not have one.
The HAPI must be correctly aligned to the desired approach path and must account for the vessel's trim and heel. On a vessel that changes trim with fuel load, the HAPI alignment should be checked.
Guest lighting: Yachts are designed to look spectacular at night. Decorative lighting (underwater lights, deck ambient lighting, superstructure accent lighting) can create visual clutter that makes it harder for the pilot to identify the helideck from the air. All non-essential external lighting should be dimmed or extinguished during night helicopter operations.
Bridge window reflections: Bright internal lighting on the bridge can create reflections that blind the bridge team to the helideck situation outside.
Light pollution from nearby vessels: At anchor in a busy anchorage (e.g., Monaco, Antibes, Mykonos), the light pollution from surrounding vessels can make it difficult for the pilot to visually acquire the correct vessel. Ship identification is critical.
An HMS is an electronic system that measures and displays the environmental conditions at the helideck in real-time.
The HMS should calculate and display whether the vessel motion is within the operational limits for the helicopter type being operated. Different helicopter types have different pitch, roll, and heave limits.
CAP 437 requires an HMS for offshore helidecks. Flag state yacht codes may also require or recommend an HMS.
On yachts: many smaller yacht helidecks do not have a dedicated HMS. The captain or HLO may rely on the vessel's standard motion sensors and bridge instruments, which do not present the data in the format needed for helicopter operational decisions. A dedicated HMS is a relatively inexpensive addition to a helideck and should be considered essential for any yacht that conducts regular helicopter operations, particularly in open sea conditions.
The HMS data should be communicated to the pilot before and during the approach. This requires a communications link (radio or data link) between the vessel and the helicopter. Some HMS systems can transmit data directly to the pilot's cockpit display via a data link, allowing the pilot to see real-time vessel motion data during the approach. This is standard in offshore operations but rare on yachts.
CCTV cameras positioned to cover the helideck provide several safety benefits:
On yachts: many yachts have extensive CCTV systems for security purposes, but the helideck is often not covered by a dedicated camera — or the camera angle does not provide a useful view of the entire deck. When specifying the yacht's CCTV system, ensure the helideck is properly covered.
Reliable communications between the pilot, the HLO, and the bridge are essential for safe helicopter operations. Communication failures are a contributing factor in helicopter incidents.
The yacht should publish its helideck communications frequencies and procedures in the helideck operations manual and provide this information to the pilot/AOC holder before the first flight.
The firefighting capability of a yacht helideck is the single most important safety system. If the helicopter has a fuel leak, an engine fire, a post-crash fire, or a refuelling spill, the difference between a survivable event and a catastrophe is the speed and effectiveness of the firefighting response.
AFFF is the standard firefighting agent for aviation fuel fires. It works by forming a thin aqueous film over the surface of the burning fuel, sealing off the oxygen supply and suppressing vapour release.
AFFF concentrate is mixed with water at a typical ratio of 3% or 6% (depending on the product) to produce foam solution. The foam solution is then aerated through nozzles to produce expanded foam that flows over the fuel surface.
CAP 437 specifies minimum foam solution application rates and duration. For a yacht helideck, the minimum is typically: application rate of 8.2 litres per square metre per minute, for a minimum of 5 minutes, with reserve for an additional 5 minutes (10 minutes total). The total foam solution quantity depends on the helideck area.
AFFF concentrate has a shelf life (typically 10-25 years depending on storage conditions and product type). It must be tested annually (using the refractivity or proportioning test) to verify it still meets specification. Expired or degraded foam concentrate will not perform correctly in a fire.
FMS are remote-controlled foam monitors (turrets) positioned around the helideck perimeter. They can be operated from a safe distance, directing a concentrated stream of foam onto the fire.
Advantages: Keeps the firefighting crew at a safe distance from the fire. Can cover the entire helideck from multiple angles.
Disadvantages: The foam is projected from the perimeter ONTO the fire. If the fire is underneath the helicopter (e.g., a fuel leak from the belly), the foam may not penetrate to the base of the fire. The FMS is most effective for pool fires on the deck surface.
DIFFS is the most effective helideck firefighting system available. Foam nozzles are integrated into the helideck surface itself, discharging foam UPWARD through the deck.
The foam emerges directly at the fuel surface — underneath and around the helicopter — rather than being projected from the perimeter. This is critically important because aviation fuel pool fires spread rapidly and the fire can be shielded from perimeter monitors by the helicopter's own structure.
DIFFS provides uniform coverage across the entire helideck surface simultaneously. It does not rely on a crew member aiming a monitor correctly under the stress of an emergency. DIFFS can be activated automatically (triggered by fire detection) or manually. Automatic activation is preferred — every second of delay in firefighting response increases the severity of the fire.
DIFFS is increasingly standard on new-build superyacht helidecks. Retrofit to existing helidecks is possible but requires significant modification to the deck structure to accommodate the under-deck nozzles, piping, and foam supply. Bayards (the Dutch helideck specialist) is one of the leading manufacturers of integrated helideck systems including DIFFS.
In addition to the main system (FMS or DIFFS), portable extinguishers must be positioned at the helideck:
Extinguishers must be serviced and certified annually. They must be positioned for immediate access — not stored in a locker below decks.
At the HLAC inspection, the AIB should require a full functional test of the firefighting system. If they don't, the HLAC is being issued based on the assumption that the system works — not evidence that it does.
Some large yachts and expedition vessels have more than one area that can be used for helicopter operations — typically a main helideck (aft) and a secondary landing area (forward or on a support vessel alongside). Additionally, yacht operations often involve a mother vessel and a support/shadow vessel, each with its own helideck. When both vessels are in close proximity (as they normally are), helicopter operations to one vessel create risks for the other.
Some yachts carry more than one helicopter (e.g., a large twin-engine for passenger transport and a smaller single-engine for recreational use). If both helicopters are on the same helideck (which is very rare due to space constraints) or in the same hangar, specific procedures are needed for movement, securing, and separation.
If the helicopters operate from different locations (one from the yacht, one from the support vessel), the deconfliction rules above apply. Flight planning must account for both helicopters' movements to prevent airborne conflicts.
The fundamental rule: One deck, one helicopter, one operation at a time. Anything more complex requires formal procedures, trained coordination, and clear communication. "We'll figure it out on the day" is not a safety plan.
A helicopter ditching (controlled landing on water) or crash into the sea near the vessel is the most serious emergency scenario in maritime helicopter operations. The response must be immediate, coordinated, and practised.
Depending on the helicopter type, it may float for a short time (seconds to minutes) or capsize and sink almost immediately. Most helicopters are top-heavy (engines and gearbox above the cabin) and will invert within seconds of water contact.
Occupants must egress (escape) from a potentially inverted, sinking, submerged helicopter in darkness (the cabin floods and visibility drops to zero). This is why HUET (Helicopter Underwater Escape Training) exists.
Occupants wearing life jackets should NOT inflate them inside the helicopter — an inflated life jacket in an inverted cabin will pin the occupant against the ceiling (now the floor) and prevent them from reaching the exits. Life jackets should be inflated only after leaving the aircraft.
The Emergency Locator Transmitter (ELT) should activate automatically on water contact, alerting search and rescue services.
A helicopter ditching response drill should be conducted at least annually, ideally every 6 months. The drill should involve: sounding the alarm, launching the rescue boat, approaching a simulated casualty in the water, recovering the casualty on board, and providing first aid.
The drill should be timed. If the rescue boat takes 10 minutes to launch after the alarm, survivors in cold water may already be hypothermic or drowned. The target should be: rescue boat in the water within 3 minutes of the alarm.
Many yacht crews have never conducted a helicopter ditching drill. This is a failure of the vessel's Safety Management System.