Fire fighting

The aircraft departed Marseille-Marignane Airport in the afternoon and was dispatched in the area of Taradeau where a forest was on fire. Two helicopters, two others Tracker and five Canadair CL-415 were also dispatched to the same zone. The pilot was approaching the area on fire when he momentarily lost visual contact with the ground. The aircraft impacted trees and crashed, bursting into flames. The pilot escaped with minor injuries while the aircraft was destroyed by fire.

The crew departed Rome-Ciampino Airport in the afternoon on a fire fighting mission in Forte dei Marmi, north of Pisa. Following two successful missions, the crew was attacking the fire in hilly terrain and low altitude when the aircraft collided with power cables. A fire erupted on the right side of the aircraft and the crew lost control of the airplane that crashed in a residential area. Both pilots were killed while there were no injuries on the ground.

The pilot, sole on board, was engaged in a fire fighting mission and was supposed to leave Rainbow Lake for High Level. During the takeoff roll, at a speed of 90 knots, one of the engine lost power. The pilot rejected takeoff and released the load of fire retardant. Unable to stop within the remaining distance, the aircraft overran, rolled for about 1,200 feet then struck a drainage ditch and came to rest. The pilot was seriously injured and the aircraft was damaged beyond repair.

Owned by SOREM, the aircraft was dispatched in Portugal and leased to OMNI - Aviação e Tecnologia for fire fighting missions. Following a scooping mission in the Aguíeira Reservoir off Chamadouro, the crew increased engine power and started a takeoff procedure when control was lost. The takeoff was abandoned but the aircraft collided with the shore and came to rest. Both pilots escaped uninjured and the aircraft was damaged beyond repair.

The aircraft was dispatched over the region of Esine to fight a forest fire under call sign Tanker 9. The area under fire was located on the southern slope of the Val Camonica, about 8 NM northeast from Lake Iseo. While approaching the zone to be treated, the aircraft struck trees and crashed on the mountain slope. Both pilots were injured, one seriously, and the aircraft was destroyed.

The aircraft took off from Runway 16 at the Cranbrook Airport, British Columbia. Two pilots were on board to conduct a fire-management mission on a small ground fire (designated N10156) two nautical miles southwest of the township of Cranbrook. Seven minutes earlier, the partner “bird dog” aircraft, a Turbo Commander, also departed Cranbrook to assess the appropriate aircraft flight path profiles and to establish the most suitable fire-retardant delivery program for the ground fire. Following the flight path demonstrations by the bird dog aircraft, Tanker 86 proceeded to carry out the retardant drop on the fire. After delivering the specified retardant load, Tanker 86 was seen to turn right initially then entered a turn to the left. At 1221 MST, the Electra struck the terrain on the side of a steep ridge at about 3900 feet above sea level. The aircraft exploded on impact and the two pilots were fatally injured. An intense post-crash fire consumed much of the wreckage and started a forest fire at the crash site and the surrounding area. The on-board emergency locator transmitter was damaged by the impact forces and did not activate.

The aircraft with a single pilot on board was performing firefighting operations in the vicinity of Lake Wicksteed, approximately 10 nautical miles north of Hornepayne, Ontario. The aircraft was scooping water from Lake Wicksteed for the nearby fire. The lake is approximately 7300 feet in length with gentle rising terrain along its shoreline. This was the third scooping from the lake, and the approach was flown in an easterly direction in light wind conditions. The pilot performed the inbound checks, lowered the water probes to begin filling the float water tanks, and touched down on the lake. Within a short time, he observed water spraying from the overflow vents located on top of the floats, indicating that the tanks were filled to capacity. He pressed a button on the yoke to retract the probes, and the aircraft immediately nosed over into the lake in a wings-level attitude and began to sink. The accident occurred at approximately 1800 eastern daylight time. The pilot extricated himself from the aircraft and held on to the side of the partially submerged aircraft. A witness to the occurrence immediately boarded a powered, aluminum boat and went to assist the pilot, while a second witness travelled to Hornepayne to notify the authorities and emergency services. Once the pilot reached the shore, he was taken to a nearby cottage where he remained until emergency services arrived. The aircraft came to rest on the bottom of the shallow lake in an inverted attitude with the floats above the surface of the water.

The airplane was maneuvering to deliver fire retardant when its left wing separated. Aircraft control was lost and the airplane crashed into mountainous terrain. A witness on the ground took a series of photographs that showed the air tanker's left wing separating at the wing root and the remaining airplane entering a 45-degree dive to the ground in a counterclockwise roll. An examination of the airplane wreckage revealed extensive areas of preexisting fatigue in the left wing's forward spar lower spar cap, the adjacent spar web, and the adjacent area of the lower wing skin. The portion of the wing containing the fatigue crack was obscured by the retardant tanks and would not have been detectable by an exterior visual inspection. An examination of two other air tankers of the same make and model revealed the area where the failure occurred on the accident airplane was in a location masked by the airplane's fuselage construction. The airplane was manufactured in 1945 and was in military service until 1956. It was not designed with the intention of operating as a firefighting airplane. In 1958, the airplane was converted to civilian use as an airtanker and served in that capacity until the time of the accident. The investigation revealed that the owner developed service and inspection procedures for the airtanker; however, the information contained in the procedures did not adequately describe where and how to inspect for critical fatigue cracks. The procedures were based on U.S Navy PB4Y-2 airplane structural repair manuals that had not been revised since 1948.

The airplane was making a fire retardant drop over a mountain drainage valley when the wings separated from the fuselage. A videotape of the accident sequence showed the airplane as it flew down the valley and proceeded to make a fire retardant drop. When the drop was almost completed, the airplane's nose began moving up, and the airplane started to arrest its descent and level out. The nose of the airplane continued to rise, and the airplane's wings folded upward until they detached from the fuselage at the center wing box beam-to-fuselage attachment location. Close examination of the video revealed that the right wing folded upward first, followed by the left wing about 1 second later. Metallurgical examination of the center wing box lower skin revealed a 12-inch long fatigue crack on the lower surface of the right wing beneath the forward doubler, with two separate fatigue crack initiation sites at stringer attachment rivet holes (which join the external doubler and the internal stringers to the lower skin panel). The cracks from both initiation sites eventually linked up to create a single crack. The portion of the wing skin containing the fatigue crack was covered by a manufacturer-installed doubler, which would have hidden the crack from view and, therefore, prevented detection of the crack from a visual inspection of the exterior of the airplane. The investigation found that the airplane was probably operated within the maximum takeoff gross weight limits specified in the airplane flight manual. The airplane was delivered new to the U.S. Air Force (USAF) in 1957 and was retired from military service in 1978. The U.S. Forest Service (USFS) acquired it from the USAF in 1988 for use as a fire suppression tanker. Between 1978 and 1988, it was kept in a desert storage facility. It was transferred to a civilian contractor for firefighting operations and modified for that role, then sold to a Part 135 operator. The airplane was certificated by the FAA in the restricted category under a type certificate held by the USFS. A Lockheed study concluded that firefighting missions were substantially more severe than typical military logistics operations and aircraft operated in this role would require inspection intervals as much as 12 times more frequently than typical military transport usage for meeting damage tolerance requirements. Concerning the detectability of the cracks, Lockheed reported that nondestructive x-ray inspection methods in current industry and military depot level maintenance processes could have detected, with high confidence, the fatigue cracks when they were 0.50 to 0.75 inch long. Inspection intervals appropriate for this detectable crack size can be determined from a damage tolerance crack growth analysis; however, this requires an extensive knowledge of the operational loads environment and internal stresses of the C-130A wing such as would be found in a military depot level maintenance program. The operating limitations accompanying the restricted certificate specified that it be flown and maintained in accordance with the then-current (1988) USAF technical orders for the C-130A. The USAF depot level maintenance program was not included in the maintenance technical orders and was not individually specified on the certificate's operating limitations. The limitations letter did not specify compliance with USAF maintenance program modifications/amendments in technical orders issued after 1988. The operator devised a maintenance and inspection program based on the specified USAF maintenance technical order but did not develop a depot level inspection requirement to ensure continued long-term airworthiness and damage tolerance that would account for the stresses on the airplane resulting from its new firefighting role and the increasing age of the airplanes. Investigation found that there are five separate FAA-issued type certificates owned by five separate firms for the C-130As used as tankers. Although the five certificates have similar maintenance requirements, none are standardized, there is no depot level maintenance program specified for any of them, and none require full compliance with all military airworthiness technical orders. In 1991, the Department of Interior (DOI) began to doubt the continued airworthiness of the C-130A firefighting tanker fleet and was specifically concerned that the lack of a depot level maintenance program or any requirement for compliance with all military airworthiness technical orders could compromise the safety of the airplane. The DOI asked the FAA to standardize the type certificate for the C-130A and mandate improvements in the maintenance and inspection requirements. In a written opinion, the USAF agreed and urged the FAA to mandate that operators establish a depot level type continuing airworthiness program for the airplane and mandate compliance with all technical orders. In a series of meetings held in 1993, FAA management internally agreed that the DOI and USAF positions held merit and began to develop requirements. In late 1993, in a meeting between the FAA, DOI, USFS, and the airplane operators, the USFS and the operators objected to the idea of depot level maintenance programs and full compliance with all technical orders on the basis of the potential economic impact of these requirements. As of the time of the accident, the FAA had not standardized the existing five type certificates nor had they imposed any additional maintenance or inspection program requirements.

During an aerial fire suppression mission for the California Department of Forestry (CDF), two Grumman TS-2A airplanes, operating as Tanker 92 (N442DF) and Tanker 87 (N450DF), collided in flight while in a holding pattern awaiting a retardant drop assignment on the fire. All of the airplanes fighting the fire were TS-2A's, painted in identical paint schemes. The Air Tactical Group Supervisor (AirTac) was orbiting clockwise 1,000 feet above the tankers, who were in a counterclockwise orbit at 3,000 feet mean sea level (msl). The pilots of both aircraft involved in the collision had previously made several drops on the fire. Records from the Air Tac show that Tankers 86, 91, and 92 were in orbit, and investigation found that Tanker 87 was inbound to enter the orbit after reloading at a nearby airport base. AirTac would write down the tanker numbers as they made their 3-minutes-out call, and usually ordered their drops in the same order as their check-in. The AirTac's log recorded the sequence 86, 91, 21, and 92. The log did not contain an entry for Tanker 87. Other pilots on frequency did not recall hearing Tanker 87 check in. Based on clock codes with 12-o'clock being north, the tankers were in the following approximate positions of the orbit when the collision occurred. Tanker 92 was at the 2-o'clock position; Tanker 86 was turning in at the 5-o'clock position; and Tanker 91 was in the 7-o'clock position. The AirTac's log indicated that Tanker 92 was going to move up in sequence and follow Tanker 86 in order to drop immediately after him. Post accident examination determined that Tanker 92's flaps were down, indicating that the pilot had configured the airplane for a drop. Tanker 92 swung out of the orbit wide (in an area where ground witnesses had not seen tankers all day) to move behind Tanker 86, and the pilot would likely have been focusing on Tanker 86 out of his left side window. Tanker 87 was on line direct to the center of the fire on a path that witnesses had not observed tankers use that day. Reconstruction of the positions of the airplanes disclosed that Tankers 86 and 91 would have been directly in front of Tanker 87, and Tanker 92 would have been wide to his left. Ground witnesses said that Tanker 87 had cleared a ridgeline just prior to the collision, and this ridgeline could have masked both collision aircraft from the visual perspective of the respective pilots. The right propeller, engine, and cockpit of Tanker 92 contacted and separated the empennage of Tanker 87. The propeller chop was about 47 degrees counterclockwise to the longitudinal axis of Tanker 87 as viewed from the top. The collision appeared to have occurred about 2,500 feet, which was below orbit altitude. CDF had no standard operating manual, no established reporting or entry point for the holding orbits, and a tanker could enter any point of the orbit from any direction. While no standardized procedures were encoded in an operating manual, a CDF training syllabus noted that a tanker was not to enter an orbit until establishing positive radio contact with the AirTac. The entering tanker would approach 1,000 feet below AirTac's altitude and stay in a left orbit that was similar to a salad bowl, high and wide enough to see and clear all other tankers until locating the tanker that it was to follow, then adjust speed and altitude to fall in behind the preceding airplane.