Giving old aircraft a new lease of life as aerial firefighters

The spokesperson commented: “MATRIX™ Technology will increase safety and mission success. Flights that are pilot-optional via fly-by-wire technology will allow for flight in degraded visual environments (DVE) like wind and sandstorms. In military operations, it will also allow for the recovery of unmanned systems and increased cargo transport.” In fact, the aircraft, in an optionally piloted capacity, is now being considered for nighttime aerial firefighting, which will dramatically decrease the loss of life and property in wildfires.

Erickson’s new water cannon can tackle difficult urban high-rise firefighting demands, and will also provide enhanced precision for wildland firefighting. Finally, the new composite rotor blades, which have just been approved by the Federal Aviation Administration, offer an 88-per-cent increase in payload compared to metal blades, and have the capacity to extend aircraft performance.

Dash 8-Q400 Airtanker

The De Havilland Canada DHC-8, commonly known as the Dash 8, is a series of turboprop-powered regional airliners, introduced by de Havilland Canada (DHC) in 1984. All Dash 8s delivered from the second quarter of 1996 (including all Series 400s) include the Active Noise and Vibration System designed to reduce cabin noise and vibration levels to nearly those of jet airliners.

To emphasize their quietness, Bombardier renamed the Dash 8 models as the Q-Series turboprops.

Conair manufactures modified RJ85, Q400MR, and Q400AT aircraft for use in aerial firefighting and transporting people/cargo in support of emergency response operations. “Since Conair started, we’ve modified over 15 different aircraft types into airtankers, producing over 150 different aerial firefighters.” says Jeff Berry, Director of Business Development at Conair. The company recognizes that the time has come to modernize fleets, keeping the firetrucks in the sky when the call comes, acknowledging that legacy airtankers are reaching the end of their sustainable life. Conair’s answer to the future of aerial firefighting is the Dash 8 Q400AT. “The Q400AT is fast, fuel efficient, and tactically flexible, operating both initial attack as well as sustained support actions from remote or urban bases. And it has strong OEM support, guaranteeing availability of parts and servicing for years,” continued Jeff. The tanker can carry 2,640 US gallons (10,000l) of retardant, foam or water and travel at 340 knots (630 km/h).

To convert the aircraft into an airtanker, Conair outfits the frame with a proprietary Next Generation Retardant Delivery System (RDS). A team of Conair engineers designed the custom, purpose-built composite tank to deliver a 10,000-l payload of water, gel or retardant, with the ability to provide multiple coverage levels from a single drop using a computer-controlled flow system operated by pilots, ensuring the airtanker could respond to a wide variety of wildfire types, from grass to dense forest.

The tank is attached to the exterior of the aircraft under the center fuselage, enabling the interior of the cabin to remain pressurized, creating a safer environment for pilots by reducing fatigue. In a certified, multi-role version of the aircraft, the 220-inch-long tank can be removed and reinstalled in a few hours. This enables the aircraft to efficiently perform additional roles in emergency response, including cargo, passenger, medevac, or combi-transport, without compromising its aerial firefighting capability.

To enhance its superior aerial firefighting performance, the Q400AT flight deck is equipped with a Conair-developed, and Transport Canada-certified, Flight Envelope Awareness System, which provides pilots with enhanced safety awareness information such as instantaneous G-Loading, slow speed awareness, flap over-speed advisory, and angle of attack detail. Conair ‘proactively improves management systems with innovative technologies that go beyond regulatory compliance’, said the company.

The Q400MR has been in operation in France for the past 15 years while the new Q400AT just completed its first bushfire season in Australia, with its first fire season in North America scheduled for this summer.

AT802 Air Tractor/Fire Boss

When equipped with amphibious floats installed by Wipaire, the AT-802F becomes the Fire Boss scooper air tanker, able to land on and scoop water from nearby lakes, rivers and reservoirs. From a nearby water source, the 802F Fire Boss can deliver up to 14,000 gallons per hour for extended attack or ground support. An unimproved runway or water-side ramp and fuel are all it needs.

Powering the Fire Boss is the Pratt & Whitney PT6A-67F turboprop engine, which boasts 1,600 horsepower, and allows maneuverability in mountainous and / or hot operating environments.

Air Tractor’s Gen II Fire Retardant Dispersal System (FRDS) offers an extensive update to the original FRDS system, and includes more than 270 lbs of weight reduction, all-electric operation, 25-per-cent more flow rate, integrated AFF tracking / ATU telemetry system, integrated foam injection control, and, according to the company, has much simpler operation than previous systems.

In the cockpit, the FRDS Pilot Interface offers a multi-function DataVault controller with an anti-reflective, color OLED screen and backlit silicone button overlay for clarity and visibility in all lighting conditions. When approaching the fire line, pilots can dial in the coverage level, drop amount and ground speed; then, with a press of the trigger, the FRDS computer does the rest – opening and closing the fire gate doors while compensating for G-loads, gallons in the hopper, and ground speed to deliver consistent coverage along the entire drop.

AT-802F aircraft with Gen I and Gen II firegate systems can be upgraded with Gen III FRDS components. The Gen III firegate can be easily retrofitted to AT-802F airplanes equipped with Gen I and Gen II firegates. Vent doors, fairings, brackets, E-dump handle, and many other items from earlier FRDS systems can be re-used – an important aspect of commonality of parts.

DC-10

The McDonnell Douglas DC-10 is an American wide-body airliner manufactured by McDonnell Douglas, intended to succeed the DC-8 for long-range flights. It first flew in August 1970, and was introduced in August 1971 by American Airlines. Since 2006, DC-10 Air Tankers have been in service as aerial firefighting units. The aircraft, operated by the joint technical venture 10 Tanker Air Carrier, are converted wide body McDonnell Douglas DC-10-30 passenger jetliners.
10 Tanker Air has been operating (since 2006) as one of the only fleets in the world with newly developed VLATs (very large air tankers), four of which are currently in operation. Each one can carry a retardant payload of 9,400 gallons at an approximate weight of 84,600lbs. The tank system is able to drop a full load of retardant in four seconds, from a height of between 200 and 300 feet above ground level. Each aircraft is followed by seven technicians, who carry a range of spare parts and equipment with them.

Bill Pilcher, Director of Business Development for 10 Tanker Air Carrier, explained to AirMed&Rescue why the company chose the DC-10 as a firefighting aircraft in the first place, identifying four key attributes:
“We wanted to mount high-volume retardant tanks externally; the DC-10 fuselage is high enough above the ground to permit attachment of external tanks with 45,000-l capacity; the three jet engines provided for system redundancy and superior power-to-weight ratio, especially important for maneuverability; and the DC-10 could easily carry the additional weight.”

Technical adaptations made immediately in order to bring the aircraft up to spec as a firefighting plane include removal of all passenger seating and overhead bins, as well as the removal of the main landing gear. A Supplemental Type Certificate was required and obtained for the tank mounting system.
Asked about how the longevity of the aircraft as firefighting assets would be assured, Pilcher said: “We will periodically review the current computer-controlled drop system, and we have also ensured that our software architecture allows for upgrades and modifications.”

BAe 146

When Neptune Aviation Services replaced its Korean War Era, former US Navy P2V Neptunes, it selected the BAe 146 jet airliner as its next-generation aerial tankers. Once operating as many as 11 P2Vs as air tankers for fire retardant dropping, Neptune retired its last ones in 2017, the year before its ninth – and, to date, final – BAe 146 was modified to assume that mission. Built between the late 1980s and early 1990s, the aircraft were available for under US$2 million each. Pre-purchase, particular attention was paid to the condition of the airframes, landing gears and engines.

On average, each tanker conversion, carried out by Neptune’s technical staff, took three months, commencing with the removal of the passenger interior, and installation of a single 3,000-US-gallon (11,356.24-l) tanking system. The tank, which includes a fault detection and monitoring system, is connected to five valves, located in the former baggage compartment area – two forward and three aft of the main landing gear bay – allowing for the controlled release of the retardant. Five openings at the bottom of the fuselage for retardant discharge were added, with each reinforced by doublers.

“The goal was to maintain the BAe 146’s standard airworthiness certification. This required all the pieces of the tank to fit through the original passenger door, since the airliner was not built as a freighter with a wide cargo door,” said Nic Lynn, Neptune’s Vice-President of Operations. “We built a mockup of the BAe 146 airframe, and manufactured the tank on that fixture. It verified that when the tank was dissembled, the individual pieces would fit through the door, to be reassembled on the aircraft.”

Neptune equipped all its BAe 146s with a light operational load monitoring system, which measures 34 parameters from accelerations to airspeed, altitude, location, and fuel and retardant quantity. Additionally, a heavy operational load monitoring system tracks the same 34 parameters, and records input from 27 strain gages and three additional accelerometers. All data generated from those sources is downloaded to a laptop primarily through Wi-Fi, but also via cable as a backup.

“The analysis ensures that we are maintaining the aircraft safely. Using the data, we are able to update our inspection program, which is done every two years,” Lynn noted.

In fact, the aircraft’s new role has necessitated special inspections. For instance, those parts of the airframe that come into contact with the retardant are inspected for corrosion. The engine ignitors, used during takeoff and approach in passenger operations, are also inspected. “With each retardant run equating to a low approach, our ignition systems operate more frequently than they did in airline usage, so we have adjusted their inspection intervals to accommodate this,” Lynn noted.

C-130

The C-130 entered service with the US in 1956, followed by Australia and many other nations. During its years of service, the Hercules family has participated in numerous military, civilian and humanitarian aid operations. The C-130 Hercules is the longest continuously produced military aircraft at over 60 years, with the updated Lockheed Martin C-130J Super Hercules still being produced now. It can be adapted for use as an aerial firefighting asset through the addition of a firefighting retardant delivery system.