This month’s Lessons Unlearned concerns two separate accidents that occurred within a month of each other; they were almost identical in cause; the two aircraft involved were also from the same operator. There were many factors about these two accidents that should have been tackled in 2002; unfortunately, these accidents never received the attention they deserved.
LAX02GA201: On June 17, 2002, a Lockheed C-130A, N130HP, crashed while performing a fire retardant delivery run to extinguish a forest blaze; the accident happened near Walker, California. The left wing separated moments before the right wing, itself, separated from the fuselage; the aircraft spiraled counter-clockwise into the terrain, the crew receiving fatal injuries.
DEN02GA074: On July 18, 2002, a Consolidated-Vultee P4Y-2, N7620C, crashed while performing a fire retardant delivery run to extinguish a forest blaze; the accident happened near Estes Park, Colorado. The left wing separated, resulting in a counter-clockwise spiral into the terrain, the crew receiving fatal injuries.
Both aircraft belonged to Hawkins and Powers (H&P) and were operating as Public Use, contracted to the Department of the Interior (DOI) to provide aircraft, pilots, firefighting services, etc. Because of the Public Use status, the maintenance programs were approved under different requirements than most Title 14 Code of Federal Regulations (CFR) air operators, e.g. Part 121 or 135, with more robust maintenance programs. Both aircraft were manufactured decades earlier; the C-130A was manufactured in 1957 and the P4Y-2 was rolled out in 1945.
Public Use Aircraft are (by the 1998 definition used at the time), “per Section 40102 (a) (37) of Title 49 of the United States Code (B) does not include a government-owned aircraft – –
- Transporting property for commercial purposes; or
- Transporting passengers other than – –
- Transporting (for other than commercial purposes) crewmembers or other person aboard the aircraft whose presence is required to perform, or is associated with the performance of, a governmental function, such as firefighting, search and rescue … geological resource management.
An aircraft described … to be a public aircraft for the purposes of this part without regard to whether the aircraft is operated by a unit of government on behalf of another unit of government, pursuant to a cost reimbursement agreement [i.e. contract] between such units of government, if the unit of government on whose behalf the operation is conducted certifies to the Administrator of the Federal Aviation Administration (FAA) that the operation was necessary to respond to a significant and imminent threat to life and property (including natural resources) and that no service by a private operator was reasonably available to meet the threat.”
At the time of the accident, Public Use aircraft, as described in this definition, were contracted to perform functions for local and federal government agencies that government could not perform itself, e.g. provide firefighting services on an as-needed basis. The DOI could not provide firefighting assistance to its Forestry Department because they were not equipped, e.g. no aircraft, pilots, mechanics and firefighters. Air Operators, such as H&P, on the other hand, had the means to provide the service, under contract.
The issue with this was that H&P’s maintenance program was not as robust as a 14 CFR Part 121 or Part 135, ten or more operator, that usually employed a Continuous Aircraft Maintenance Program. All H&P’s aircraft were under an Approved Aircraft Inspection Program (AAIP); though approved, the program lacked the inspection attention demanded of large aircraft. H&P’s accident aircraft were manufactured for the military and before the first Maintenance Steering Group (MSG) in 1968; the continuous inspection programs were improvised by H&P with engineering assistance.
Why is this important? The MSG program introduced maintenance manufacturers’ procedures that would be modified with the changing industry, e.g. digital technologies or composites. From MSG-1 through MSG-3, the maintenance programs reflected the findings of accidents previously investigated; one in particular was Aloha 243, accident number AAR/89-03. In this accident, the crown of a B737-200 tore away in flight from the forward bulkhead to the wing due to failures in corrosion and metal stress inspections available at the time. On November 29, 1993, FAA Order 8300.12 introduced requirements for all commercial operators to create a corrosion prevention and control program (CPCP) for each of their fleet aircraft, including aircraft manufactured before MSG-1, e.g. DC-8.
H&P’s aircraft, while flying under the public use umbrella, were not required to have a CPCP. The accident aircraft were manufactured much earlier – the C-130A (1957) and P4Y-2 (1945) – for the military, who does not subscribe to most FAA rules. H&P’s maintenance programs were built for each aircraft they used, mostly military surplus, and, at the time of the accidents, did not employ a CPCP. Air Operators, e.g. 14 CFR part 121 and 135, ten or more, as part of their aging aircraft inspections, incorporated many structural inspections following the Aloha 243 accident; they fine-tuned or increased the scope of those programs after the introduction of FAA Order 8300.12.
The H&P C-130A was videoed executing its final run, just before the wings departed and well into its impact; the P4Y-2 was photographed with the missing left wing. It is probable that, if not recorded, the investigation may have missed the stress cracks or corrosion that contributed to the two accidents in the post-crash fire, especially the C-130A, since a double wing departure would have been considered highly unlikely. Furthermore, firefighting accidents would not have demanded the attention of a full National Transportation Safety Board major investigation, which would include structural engineering experts.
There is not an aircraft manufacturer committed to designing and building firefighting aircraft; the limited need does not encourage the investment. H&P, and other air operators like them, do not have the financial means to be limited customers for a late model firefighting fleet; the contracts they have do not generate enough money to upgrade. Additionally, the US government cannot invest in non-military aircraft for specifically performing firefighting, nor can it provide the start-up procedures necessary for such an air operation.
Instead, operators, like H&P, must rely on a maintenance workforce who are jacks-of-all-trades; from sheet metal repairs to avionics, from hydraulics to windshield repairs, for aircraft fleets that are no longer manufactured and have no spare parts.
These two-accident aircraft were part of a fleet of former military aircraft. The P4Y-2 was a World War II Pacific Theater bomber, whose purpose was to drop heavy ordinance loads. With fire retardant tank modifications, the bombers became new types of bombers. For the military, the C-130A slid equipment out the rear ‘ramp’ door, ‘dropping’ heavy payloads during straight low-level runs. Neither aircraft was designed to perform under the extreme aerodynamic forces experienced in firefighting. The aircraft would fly into a low lying area, drop the extinguisher and pull up hard to escape; these aerodynamic stresses were not designed into these aircraft decades prior. In addition, intense heat and temperature variants exposed the structure to further punishment while making their runs.
These days, B747 and DC-10 aircraft are being modified to conduct similar firefighting feats. Again, the former commercial aircraft, although certified with the necessary CPCP modifications, were never designed to perform these types of maneuvers. Even though the former commercial aircraft are better designed, they are still being used outside their element.
Accidents such as these, because they are of a certain operation, ‘fly under the FAA’s radar’. The firefighter operators did not modify their maintenance programs to include, e.g. CPCP. In addition, the operators did not receive much needed surveillance since their contracts require them to be anywhere, but at their home base. Many red flags were ignored; many opportunities were missed.