SAE ARP694D Aerial Refueling Lights – Design Criteria

SCOPE

This SAE Aerospace Recommended Practice (ARP) is intended to cover all external lights on the tanker and fixed wing receiver airplanes used to accomplish aerial refueling.

This ARP describes lights used for two basic types of aerial refueling: the probe and drogue, and the boom/receptacle method.

Purpose

The purpose of this ARP is to set forth the basic considerations and criteria which the design engineer should observe when designing an aerial refueling lighting system. In case of conflict between this ARP and existing military specifications, the military specification will take precedence, unless a waiver is obtained.

APPLICABLE DOCUMENTS

The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence.
Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

SAE Publications

ARP4087
Wing Inspection Lights-Design Criteria

ARP5825
Design Requirements and Test Procedures for Dual Mode Exterior Lights

AS25050
Colors, Aeronautical Lights and Lighting Equipment, General Requirements for

FAA Publications

Code of Federal Regulations Title 14, Part 23

Military Publications

MIL-A-19736 A
Air Refueling systems, General Specification for

MIL-L-6503
Lighting Equipment, Aircraft, General Specification for Installation of

MIL-L-006730
Lighting Equipment; Exterior, Installation of Aircraft (General Specification)

MIl-sTd-3009
Lighting, Aircraft, Night Vision Imaging System (NVIS) Compatible

STANAG ATP-56(B)
Air-to-Air Refuelling General Requirements

TYPES OF LIGHTS FOR AERIAL REFUELING

The type of lights required by the airplanes depends on the method of aerial refueling as indicated in Table 1. The “type of light” should not be confused with the “number of light fixtures.” A light fixture may be designed to perform the function of two or more types of lights or several fixtures may be required to perform the functions of one type of light. The designer should evaluate the aerial refueling lighting system in a manner that ensures that all required functions are performed.

Light Locations

The light fixtures should be designed and located properly so they can perform their functions. Due to the various airplane designs it is not practical to specify the exact location and design of each type of light. However, there are a number of factors which must be considered and methods of evaluation which should be used to determine if the location and design are satisfactory. Suggested design information is given in Section
Field of Vision

The field of vision of the receiver pilot and boom operator is limited. The lights must be visible when the crew members are in design eye position and the airplanes are at or near the expected relative positions. Drawings, computer simulations, and mockups showing the airplanes in various relative positions and attitudes should be used. Consideration should be given to visual obstructions such as canopy bows, heads-up displays, gun sights, etc.

Glare

Lights should not cause hot spots or glare either for the receiver pilot or the boom operator. Light sources used to illuminate the airplane should not be visible to the crew.

Reliability

When a light is operating, the crew that controls the light should be provided with an indication that the light is operating satisfactorily. Redundancy of critical lighting/light bulbs should be considered.

Contrast

Lights should be designed to have sufficient color and intensity contrast when necessary. All colored lights that can be dimmed should be operated both at full brightness and dimness to determine that the color is satisfactory. A signal light used in daytime operations should be tested to determine if the observer can positively identify that the light is “on” or “off and specific consideration should be given to flying over undercast skies where high ambient light conditions exist. The reflected illuminance from such an undercast can easily be 107600 Ix (10000 foot-candles).

Ambiguity

The signal lights should be designed to give an unambiguous signal. It should not be possible for the signal lights to direct the pilot to perform multiple operations which are in contradiction to one another.

The floodlights should outline the airplane clearly and sufficiently.

Requirements as defined herein are intended for normal operation for both day and night. Certain operations involving combat tasked tankers and receivers may require the use of night vision goggles. In this case, lighting should be provided which would be compatible with night vision goggles.

Color

The red, green, white, and yellow colors shall be within the boundaries listed below on the CIE 1931 chromaticity diagram.
The corner points define the intersections of the lines defined by the equations below with each other or with the spectrum locus.

LISUN following instruments fully meet SAE ARP694D Aerial Refueling Lights – Design Criteria

LSG-1950 Goniophotometer for Automotive and Signal Lamps

LSG-1950S Goniophotometer for Traffic Signal Lamps

LPCE-3 CCD Spectroradiometer Integrating Sphere Compact System

LPCE-2(LMS-9000) High Precision Spectroradiometer Integrating Sphere System