N6264919R0031_V-22_SSN_Att_Airfield_and_Apron.pdf

V‐22 Airfield Capability: Functional Requirements

Item Description Requirement

Helipad / Hoverpoint

Visual Flight Rules (VFR) Landings and Hoverpoint

Visual Flight Rules (VFR) landings and hover‐point require a surface area minimum of 45.7 meters by 45.7 meters with a primary landing area of 30.5 meters by 30.5 meters and a rough grade of 1 percent to 1.5 percent in one direction. Grade requirements apply to the entire primary area.

The remaining area is to be clear of obstructions and rough graded. Dust abatement is required around the primary landing area. Paved shoulders are not required unless otherwise noted.

Instrument Flight Rules

(IFR)

Landings

Instrument Flight Rules (IFR) landings require a primary surface area minimum of 91.4 meters by

91.4 meters with a primary landing area of 30.5 meters by 30.5 meters with a rough grade of 2 percent to 5 percent in any direction applied to an area 91.4 meters by 91.4 meters area centered on the helipad. Dust abatement is required around the primary landing area. Paved shoulders are not required unless otherwise noted.

Taxiway

Runway and taxiway shall be a minimum of 22.9 meters wide with recommended paved shoulders of 3.8 meters wide on each side for a total of 30.5 meters in width. If the shoulders are not paved, they must be rough graded to prevent water from ponding on the adjacent paved area.

They should be constructed of existing compacted soils, or stabilized soils with vegetative cover or liquid palliative to provide dust and erosion control against jet blast and rotor down wash.

Tow‐way Tow‐ways pavement width shall be a minimum of 10.7 meters wide with a minimum lateral clearance of 15.2 meters from centerline in each direction and a minimum vertical clearance of

12.5 meters.

Tow Tractor

Tractor runs on an engine output of a minimum of 88 horsepower and 199 foot‐pounds (ft‐lbs) of torque. It has a transmission with a minimum of three (3) forward speeds and one (1) reverse speed. Tractor shall be capable of towing aircraft weighing up to 80,000 pounds with a drawbar pull of 8,000 pounds.

General Considerations

All Landing Pads, Turn‐up Areas

Due to the MV‐22's unique Tiltrotor design and nacelle location, the area directly under the aircraft will be subject to extreme heat that can cause damage to the concrete over a period of time. This area should be* constructed out of heat resistant concrete or an application of a Sodium Silicate solution should be applied over the existing concrete, and heat resistant joint sealant to provide added protection from spalling and cracking, which can be caused by these excessive temperatures (see details below).

V‐22 Airfield Capability: Functional Requirements

Parking Apron

Because of the down wash and the heat generated from the engine exhaust it is recommended* to use higher heat resistant concrete pad on the parking apron. There will be ground turn checks that are required to be conducted prior to Functional Check Flight. These ground turns will require the aircraft be in one spot turning for extended period of time. The heat coming from the engine exhaust has been shown to deteriorate standard joint seal material in non‐heat resistant concrete pavements. It is recommended* that the following joint sealants be used:

A. Chloroprene (Neoprene) or fluorocarbon adhesive joint seals are used for locations where the V‐22 takes‐off vertically or performs ground runs for operations or training.

Chloroprene (Neoprene) joint seals are already routinely used in airfield pavements.

Neoprene has shown good chemical resistance and heat resistance up to 550 F.

B. Fluorocarbon adhesive has shown excellent chemical resistance and heat resistance up to 750 F.

C. Silicones joint seals are used for general applications areas where the MV‐22 does not take‐off vertically or perform ground runs.

These recommendations* are based on laboratory tests of the joint seal materials that were conducted by L. Javier Malvar, Research Structural Engineer, NAVFAC Pavements SME, at Port Hueneme, CA.

In addition to the Chloroprene (Neoprene) or fluorocarbon adhesive joint seal is highly recommended* that the concrete where the aircraft will be performing those ground turns have a Sodium Silicate Solution applied over the old or new concrete. This Sodium Silicate solution will help to mitigate heat issues on the concrete.

*NOTE: The recommendation to use higher heat resistant concrete and sealants are recommendations, not requirements. These recommendations are for the purpose of preventing or reducing damage to the Contractor’s facilities. The Government is not responsible for any damages or degradation to the Contractor’s facilities regardless of whether or not the Contractor undertakes to implement these recommendations. The Government also notes that has used a steel plate work‐around in some applications. Two areas of 20’x18’ (360 sq ft) (35’ apart, one for each nacelle) are overlaid with half‐inch thick steel plates are bolted into the deck to protect the concrete.