In 2017, Neptune Aviation Services replaced the last of its tanker-configured former US Navy, Cold War Era P2V Neptunes with a more modern fleet of British Aerospace (now BAE Systems) built BAe 146 regional jets. Neptune acquired the aircraft from the pre-owned airliner market and modified them at its Missoula, Montana, maintenance complex for fire retardant dropping.
Selecting and repurposing these aircraft was a game changer for the US operator. In order to understand why, some knowledge of the changes in the US aerial firefighting industry is necessary.
In 2006, in the aftermath of several fatal airtanker accidents, the US Forest Service (USFS), which is the primary customer for aerial firefighting services in the United States, indicated that after 2018, it would no longer bring the aging military and commercial aircraft – typically operated by the industry at the time – under contract. For Neptune, that mandated finding a replacement for their 11 P2Vs, for which original equipment manufacturer (OEM) support had ceased. The airframe’s builder, Lockheed Martin, had long before walked away. The same, in fact, was true for the aircraft’s Curtiss-Wright, twin-piston R3350 radial engines, and two Westinghouse J34 jet-assist powerplants. With OEM assistance gone, Neptune took on some 90 percent of the ancient airframes’ parts and labor support.
“The USFS wanted a next-generation airtanker,” said Greg Jones, Neptune’s Vice-President, Project Development. “The government told the industry it wanted a turbine-powered aircraft capable of carrying 3,000 gallons (11,356.2 liters) of fire retardant. The aircraft also had to have manufacturer support in the firefighting environment and compatibility with the USFS tanker base infrastructure, which currently consists of 64 throughout the country. It came down to supportability, maintainability, and airframe availability at a reasonable cost.”
With a short time horizon for its P2Vs looming, Neptune brought its first BAe 146 airtanker conversion on stream in 2010. Today, it operates nine, currently under contracts with the USFS, as well as two state fire agencies. Powered by four Honeywell ALF 502 jet engines, the aircraft’s 12 years of service with Neptune have proven its suitability for aerial firefighting, according to Ryan Baer, Neptune Aviation’s Chief Pilot.
“The BAe 146 is very maneuverable which makes it an excellent aircraft for operations over challenging terrain,” he explained. “It also has reliable slow speed characteristics with a speed brake that is deployable during a drop.” Baer also cited the aircraft’s high cruising speed with a short runway capability which allows it to land at a variety of airfields.
The BAe 146, though not the fastest by today’s jet standards, has a speed advantage over the formerly operated P2V, which cruised to the fire at 170 KIAS (Knots Indicated Air Speed). With an average cruise speed of 250 KIAS below 10,000 feet, the BAe 146’s 80 knot differential enables faster flight times to fire events, often allowing deployment on fires at multiple locations within a single day. At the same time, Baer pointed out that the BAe 146 has demonstrated quick turn-around capabilities, with a load time of just eight minutes for the full 3,000 gallons of retardant. “It is common to be airborne within 30 minutes,” he said, adding that the BAe 146 has “an outstanding safety history and a robust airframe design.”
Baer also noted that in 2021, the nine airtankers dropped approximately 7 million gallons of retardant during 2,316 sorties—approximately 250 sorties per aircraft. “The 2022 fire season has been very active to date, and we expect to surpass those numbers this year,” he remarked.
Neptune’s BAe 146 fleet is deployed with a flight crew of two pilots and a cadre of two maintenance technicians, per aircraft. Used exclusively for fire retardant dropping, the aircraft can be called into play during any phase of a wildland firefighting operation, although Baer said it is common for the tankers to be used during the initial attack phase—particularly when the fire jeopardizes human lives, property, and critical infrastructure, such as powerlines or wind turbines, as examples.
“At other times the tankers are brought out to help the ground crews tie together natural and man-made fire breaks—both roads or hand-built fire lines,” he said. “We even deploy our aircraft for mopping up operations as the fire area reaches containment. That focuses on breaching up fire breaks that could be susceptible to allowing the fire to escape containment.”
As Baer explained, planning a firefighting mission varies from choreographed retardant drops, complete with lead planes and air attack planes calling the drops, to Neptune’s team of pilots making the decision to drop retardant based on fire conditions, structure protection and supporting the firefighting team on the ground.
“In general, Neptune pilots have the coordinates for the fire location programmed into the aircraft before they leave the retardant base,” he said “As the aircraft approaches the fire, the pilots are in communication with the team on the ground or the air attack aircraft that manages the aircraft assigned to the fire.”
According to Baer, situational awareness is an airtanker pilot’s most important skill. “The concept of making a retardant drop is simple. Basically, we make an approach to land, slow the aircraft down, and make the drop at a low altitude. It’s the variables that create the challenges involved in aerial firefighting,” he noted. “The wind, heat, smoke, air temperature, terrain, and air activity around the fire are all important challenges that need to be considered before a drop.”
Baer said that with conditions on the ground constantly changing the characteristics of the fire, Neptune pilots are in close contact with the team on the ground or with the fire incident commander. “While the basic mechanics of the retardant drop remain the same, pilots need to stay flexible to the changing nature of the fire and the needs of the team of fire fighters on the ground,” he stated. “Flexibility means having to adapt to congested airspace in which multiple aircraft—helicopters, lead planes, airtankers and air attack aircraft – can be working the fire.”
Safety is paramount at Neptune. “We minimize the risks of aerial firefighting through morning briefings, safety meetings, communication, practice; simulator training, flight training, flight school, and scheduled breaks away from the aircraft,” said Baer.
Neptune assures field level mission readiness for the BAe 146 with mechanics assigned as either “Crew Chiefs” or “Second Mechanic,” Greg Jones explained. Specifically, he pointed out, the Crew Chief manages ongoing maintenance, while the Second Mechanic manages the support vehicle, which transports “a highly refined inventory” of routinely needed parts and tools to keep the aircraft available while away from Neptune’s main facilities. “This gives our maintenance teams great autonomy while keeping maintenance practices safe and efficient,” he noted.
According to Jones, Neptune has managed an availability rate of 98% for the BAe 146, while spread across the country. “Successful companies in the aerial firefighting industry, such as Neptune, have developed proactive procedures regarding support for continued airworthiness away from a home base,” he said. “Our maintenance control center is operated 24/7 and is able to coordinate the continued airworthiness in conjunction with the various Neptune maintenance departments, such as airframe, avionics, and engines.”
The BAe 146 has opened the door to greater opportunities in the global aerial firefighting market. International operations, said Jones, will require that a selection of FAA approved parts and tooling be provided to a specific geographical location to cover what Neptune would anticipate being an issue. “These items will be shipped prior to an aircraft arrival. The assigned maintenance staff will be responsible to maintain the aircraft in accordance with existing FAA part 145 Repair Station and Quality Assurance procedures utilizing FAA approved technicians, parts, and flight crews,” Jones remarked.
Neptune, Jones remarked, maintains its BAe 146 fleet through an independent FAA approved supplemental type certificate (STC), specifically for Firefighting usage for the BAE 146. Since those aircraft were to be used in an entirely different role than originally designed, Neptune performed a new-usage evaluation at the time of their acquisition, Jones explained. “Loads and stresses are different, and Neptune has vast experience with usage and fatigue related issues in aerial firefighting. We utilized OEM fatigue and stress reports for the entire airframe and re-analyzed them using damage tolerance analysis for the firefighting environment.”
For example, he said, a particular airframe item in commercial usage may require an inspection each 2,000 flight cycles, in firefighting this may be lowered to repeat inspections each 500 flight cycles. This firefighting analysis applies to all Fatigue Critical Base Structure (FCBS) and airframe repairs.
Neptune’s BAe 146 maintenance program is what Jones calls “highly structured,” because it needs to account for not only the airframe and powerplant, but the aircraft’s retardant tanking system—including the tank, valves, and computer. “It differs in part from a commercial passenger aircraft because the tanking system contains additional parts, components and structures that need to be maintained, tested, and repaired,” he said.
Major checks are done at intervals of two years for a C-Check, and four years for a D-Check. In general, said Jones, Neptune’s C-Checks will require 6,000 maintenance hours to complete, while the D-Checks “are supersized maintenance procedures” taking anywhere from 30,000 to 50,000 maintenance hours to complete. The major difference between the two procedures, he added, is that during a D-Check the entire aircraft is stripped down with all equipment removed to inspect the aircraft for damage & corrosion.
Maintenance also includes avionics upgrades, when considered necessary. For example,
Neptune has retrofitted three of its aircraft with Garmin GNS 750 navigation/communication systems, with two additional installations slated for this winter. The Garmin system will provide greater reliability and intuitive user interface for Neptune’s operations.
Because Neptune performs most of its maintenance in-house, transitioning from its legacy P2V tankers to the BAe 146 required a considerable investment in support infrastructure costs – $1.5-million (US), according to Jones. “Structural modifications included modifying our maintenance hangar doors to accommodate the high horizontal stabilizer wings on the BAe 146,” he explained. “We also modified our retardant tank manufacturing facility to account for the larger 3000-gallon sized retardant tanks that we engineered for the new aircraft.” Neptune also built a jet engine stand/testing facility to work on the Honeywell ALF502R-5 engines that power the BAe 146 aircraft, he added.
In a further development, Jones reported that Neptune recently completed the purchase of two additional hangars, expanding total hangar space to just under 200,000 square feet. Some of that space, he said, might need to be modified to accommodate the BAe 146 aircraft or Neptune’s King Air 100 and Falcon 50 aircraft, used when needed to support the air tankers in the field.
For more information, go to www.neptuneaviation.com