MPP-02.3.3 vertical replenishment operating area marking, clearances and lighting

What it is

MPP-02.3.3 is a NATO Multinational Procedural Publication that fixes the minimum requirements for marking, clearances and lighting of a ship's Vertical Replenishment Operating Area (VOA): the deck space within which a helicopter's rotor, fuselage, landing gear and load clearances are provided for VERTREP, the transfer of material to or from a ship by helicopter. It concerns only loads carried externally by a cargo hook, not cargo carried inside the aircraft. Participating nations agree to mark and light their VOAs as the document specifies, and to fix separately, in the companion publication MPP-02.1, which helicopter categories a given VOA can safely take. The agreement itself is recorded in STANAG 1162, which is also the NSDD cover this record sits under.

It is not a document every NATO nation has taken on in full. The United Kingdom does not implement MPP-02.3.3 at all and uses its own national VERTREP procedures under MPP-02 instead; Italy has not implemented the lighting requirements and authorises daylight VERTREP only; Denmark records that the lighting section cannot be met on ships whose overhead floodlight is not dimmable at ABSL-class; and Estonia implements only the optional Annex F hoist-point marking. A reader checking whether this binds a specific nation's ships needs that nation's own recorded reservation, not an assumption of uniform adoption.

The VOA and its obstruction limits

A VOA is the general deck area within which rotor, fuselage, landing gear and load clearances are provided; within it, the pick-up and delivery zone is the unobstructed area where a load is actually transferred. Two obstruction classes govern how tall anything nearby may be: a Class 4 (Low Hover) VOA permits obstructions up to 1.52 m (5 ft) within the fuselage and landing gear clearance zone and 4.6 m (15 ft) within the rotor clearance zone; a Class 5 (High Hover) VOA raises those limits to 4.6 m (15 ft) and 7.62 m (25 ft). Helicopters and VOAs are also classified into four categories by rotor diameter, and a category assigned to a VOA guarantees adequate clearances for every helicopter in that category. A minimum unobstructed deck area of 36 sq m (400 sq ft) is recommended for a major VERTREP operation, though a smaller area is permitted if it is adequate to the ship's own VERTREP requirements.

Clearances (0105)

A load clearance zone of at least 3.1 m (10 ft) in any direction from the centre of the pick-up and delivery zone is recommended, and the load's approach and take-off axis should be kept clear where possible. Outside that, a fuselage and landing gear clearance zone extends port and starboard to the hull edge and forward and aft, sized to the VOA's marking type and capped at the Class 4/5 obstruction heights above. A rotor clearance zone outside that again extends to the hull edge, for a minimum of three-quarters of the largest category helicopter's rotor diameter, capped at the same heights.

Marking systems and rotor center limit lines (0106)

Markings are white or yellow over a contrasting background, with the marking's own reflectance at least 0.50 and the background's at most 0.12, so they read clearly by day and can be accentuated by lighting at night. Which of four marking systems applies depends on deck space and helicopter category:

• No additional marking, where the largest VERTREP category matches the category the ship is cleared to land.
• A marked pick-up and delivery periphery plus an athwartship rotor center limit line, for a dedicated "VERTREP ONLY" deck area.
• An optional hoist pick-up point marking, for ships with no landing or VERTREP facility at all. Its use is not based on any clearance criteria; it rests on agreement between the ship's captain and the helicopter pilot.

The rotor center limit line itself comes in four types, each tied to a different clearance geometry:

• Type 1 - a single dashed line, adequate only when the helicopter stays centred on and parallel to it.
• Type 2 - an athwartship line of Tees, not recommended for a bow VERTREP position.
• Type 2A - an additional line of alternating Tee-balls, for larger helicopters (usually Category A) than Type 2 can safely take, also not recommended for a bow position.
• Type 3 - two athwartship Tee lines, adequate only while the helicopter's rotor hubs stay between them.

Lighting (0107)

Night operations require dimmable overhead floodlights, white, yellow or red, installed to light the pick-up and delivery zone clearly without putting direct light or glare on the pilot. An additional visual reference is recommended, and the document records which nations use which system: a stabilised horizon bar (Canada, Germany, Denmark, Spain, United States), hangar-face or top floodlighting (Canada, Denmark, Spain), flush-mounted periphery and line-up lights (United States), and unstabilised horizon lights (United Kingdom, Netherlands). The chromaticity of aeronautical lights follows STANAG 3711 unless otherwise specified.

Who it binds, and how

MPP-02.3.3 does not address a supplier or a manufacturer. Its own terms address the participating nations that agree to mark and light their VOAs as specified, in practice whichever national naval authority configures a ship's deck, and, for the optional Annex F marking, the ship's captain and the helicopter pilot who agree between them whether it is safe to use. The agreement to use the publication is recorded in STANAG 1162; a nation is bound once it has taken that agreement on, and several have not, in whole or in part; see the reservations above. Edition A, Version 2 was promulgated in June 2016; the document does not state what edition or version it superseded.

How it is evaluated

MPP-02.3.3 describes no certification, audit or inspection scheme, and names no accredited body, notified body or government surveillance role. What exists is a set of dimensioned marking, clearance and lighting requirements that a nation's own naval authority would presumably check a VOA's design and fit-out against before clearing it for VERTREP; the document does not say who performs that check or how often. The Record of Reservations and National Comments show the mechanism that actually operates: each nation self-declares whether and how it implements the standard.

Getting the document

NATO publishes MPP-02.3.3 through the NATO Standardization Document Database at no charge. ComplyTrain does not sell it or host a copy; the NSDD listing for MPP-02.3.3 is the source. It is covered by STANAG 1162, the agreement recording nations' commitment to use it.

Standards it references

• AFSP-02Background