Military airfield operations in an emergency environment

Airfield Lighting Systems and Navigational Aids are the lifelines thrown to pilots every day. For military pilots, proper operation of these systems touches more than safety of the crew. It affects hundreds of military personnel and the security of the nations they represent. Aircraft entering expeditionary locations carry military members, sustainment for these military members, equipment and machinery needed for operations, strategic and tactical information, and air support for ground troops. The national security of many nations depends on air operations.

Commencement of military airfield operations is not one simple process, but a system of processes ranging from utilising an existing, aged, unlighted asphalt air strip to establishing an air strip from nothing, in an extremely austere environment. Air operations are made possible by ground support, men and women who pre-deploy to build the strips and install navigational aids to support air operations. Packaged lighting systems have proven to be an efficient means to quickly provide this initial and ongoing support, but as with everything, these systems continue to evolve and improve.

The Emergency Airfield Lighting System (EALS)

The latter quarter of the Twentieth Century saw development and U.S. Air Force adoption of the first generation of Base Expeditionary Airfield Resource portable airfield lighting, which could be transported to a forward operating location in preparation for the arrival of military personnel and their support. This system, called an Emergency Airfield Lighting System (EALS), was designed to be rapidly installed at contingency airfields and at other locations in need of temporary airfield lighting. Still in use today, it supports flying operations at night and during periods of reduced visibility from multiple sources. Included in the system is runway edge lighting, approach lighting, threshold and end lighting, taxiway lighting, precision approach path indicator (PAPI) lights, distance remaining (distance-to-go or DTG) marker lighting, and obstruction lights. The EALS can be installed and secured on all types of surfaces from sand and ice to asphalt and concrete. It provides a minimum operating strip (MOS) 50 feet wide (15 metres) x 5,000 feet long (1524 metres) or a MOS up to 150-feet wide (45 metres) x 10,000 feet (3048 metres) long, if mission dictates. Either can be operational in close to three hours.

The EALS used today by the U. S. Air Force consists of three subsystems: lighting, power and control, and packaging. Obviously, the lighting subsystem contains all the lighting and signage system components. The power and control subsystem contains the generators, constant current regulators, control panels, cabling, and protection for the installed cable. The packaging subsystem consists of equipment necessary for transport of the system and spare equipment (i.e., trailers, cable reels, containers, tools, and spare parts).

The installed EALS uses a 30 kilowatt (kW) generator to power the system and a 20kW constant current regulator. With the exception of the battery-powered obstruction lights, the entire EALS system operates on a single primary series circuit. The control panel for this series circuit has a rotary switch with three settings. The switch setting controls the intensity of the runway edge lights, approach lights on each end of the runway, threshold and end lights; taxiway lights; and DTG marker lights. The control panel also allows selection of the appropriate approach strobe segment and is switched independently of the runway lights. The system is air transportable, packed on six trailers that easily fit within the space of three aircraft pallet positions.

The EALS was not designed for permanent use, but for temporary use as a contingency lighting system. This temporary use designation allowed the designers to take advantage of several system limitations, to produce the most expedient system at the most effective cost possible. It is not designed to support instrument flight rules (IFR) operations or for when meteorological visibility is less than four statute miles (1,609 metres per statute mile). Though rated at 20kW, the factory-adjusted cores of the regulator are capable of only 13kW. This was an accepted limitation during its development because it allowed the conductors, thus the packaging, to be smaller due to the lesser capacity of the regulator and reduced supply voltage (2000 Volts). The penalty for this is that the regulator is not capable of full intensity at the maximum size MOS of 150 feet (45 metres) x 10,000 feet (3048 metres). In most expeditionary situations, this decreased intensity is acceptable.

Even though set-up and installation sound easy, assembly and connection are like any other well-constructed system. Preparation takes more time than actual installation. The location for each piece of equipment, fixture, and cable layout must be marked and re-marked prior to installation. The rules for placing and spacing the EALS lighting elements generally conform to the standard Federal Aviation Administration (FAA) and Air Force criteria (UFC 3-535-01*, Visual Air Navigation Facilities).

The Expeditionary Airfield Lighting System (EALS II)

The EALS has more than met its intended use – originally intended for use up to six months, many are still performing satisfactorily after more than seven years. But, advances in technology and changes in the Air Force’s mission have made upgrades and changes to this workhorse of a system necessary. Development is now in place through an Integrated Process Team approach. Logistics Managers, Engineers, System Maintainers and Aviators are part of the team finalising the Technical requirements for EALS II. With new technical requirements comes a new name. This time “EALS” is short for “Expeditionary” Airfield Lighting System. EALS II is the second generation of Base Expeditionary Airfield Resource portable airfield lighting and is classified as a “night-time Visual Flight Rules (VFR)” and “non-precision Instrument Flight Rules (IFR)” system. Development is well underway.

System design will include upgraded operating characteristics and expanded landing area and will take advantage of the availability of state-of-the-art technology, while exercising maximum flexibility in powering capabilities. Unlike EALS, EALS II will be capable of providing a pilot who is four statute miles away with the visual cues necessary to set up an approach and land at night and in low visibility conditions. EALS II will be capable of both overt and covert operation.

Utilising light emitting diode (LED) and digital control technology, EALS II will be a portable airfield lighting system configured in four separate modules. These modules will be deployed in a building block manner with each subsequent module augmenting a progressively larger and more complex airfield lighting package.

Module 1 will provide an initial landing zone (LZ) 90 feet wide (28 metres) x 5000 feet (1524 metres) long, with bidirectional operations capability. The objective is to make this module durable yet as lightweight and simple to install as possible, with minimal maintenance and with remote control capability. Module 2 will be a lightweight, easily installed system providing capability for a landing zone 150 feet wide (45 metres) x 5,000 feet (1524 metres) long for day and night-time precision operations using a Medium Intensity Approach Light System with Runway Alignment Indicator Lights (FAA designation is MALSR). Configuration and light photo-metrics meet those found in UFC 3-535-01*. Target design will provide approach lights on one end, runway end lights, taxiway lights, two precision approach path indicators (PAPIs), wind cone, runway distance remaining lights and markers (RDMs), mobile aircraft arresting system lights and markers, and obstruction lights. Both Modules 1 and 2 will provide stand-alone capability.

Module 3 will expand Module 2 at 2,500 foot (762 meter) intervals plus related taxiway edge lighting, RDMs and obstruction lights. Module 4 is intended to provide a second airfield approach lighting capability for bidirectional day and night-time precision operations. All fixtures and components will have battery-powered capability so that solar energy can be utilised to the maximum extent possible, while maintaining the capability to be charged by a hard-wired power supply (generator) or utility power. The entire system will meet the certification requirements of a Federal Aviation Administration-approved laboratory, thus complying with FAA Advisory Circular 150/5345-53, AIRPORT LIGHTING EQUIPMENT CERTIFICATION PROGRAM. Module layouts are shown in Figures 1, 2, 3, and 4.

Dynamic Aircraft Operations

The expeditionary operating airfield environment is no longer static, launching and receiving limited types of aircraft. Today’s expeditionary airfield must be capable of providing strategic planners multiple options to launch a mixture of both fixed wing and rotary wing capabilities for joint and combined operations. EALS II will perform as well as EALS, but expand current deployable airfield lighting capabilities from fixed wing to rotary wing. The lighter, flexible Module 1 can even be transported by rotary wing aircraft, a feat not possible with the legacy EALS. All modules of EALS II will be designed and configured to dynamically support all the temporal phases of a base: opening, establishment, and extended operation and sustainment.

In conclusion, the legacy EALS has performed superbly in its lifetime, but technology has moved on and we must soon say goodbye to a loyal friend. EALS II has been a long time in the making, but it will meet the new mission capabilities while continuing the characteristic ease of installation, operation and maintenance of the legacy EALS.

* UFC is the abbreviation for Unified Facilities Criteria. All UFCs contain design and operational requirements for a single topic for the U. S. Air Force, the U. S. Army and the U. S. Navy, in a single publication.

Figure 4: 150' x 7,500' CAT 1 Runway utilizing one Module 2, one Module 3, and one Module 4

Notes:

1. Additional information on EALS II can be obtained from The Command Electrical Engineer at HQ Air Mobility Command, The Logistics Manager and System Engineer at Warner Robins Air Logistics Center, Robins AFB, GA, and Requirements Analyst and Electrical Career Field Manager at Tyndall AFB, Florida and the U. S. Army Corps of Engineers Transportation Systems Center.
2. Figures and photographs are courtesy of the Requirements Analyst (Mr. Rodney Fisher) at Tyndall AFB, Florida and the Civil Engineer Maintenance, Inspection, and Repair Team (CEMIRT) also located at Tyndall AFB.