Scheduled Revenue Flight

A TAIC investigation found that there was no evidence of any component malfunction that could cause a double engine failure, although due to seawater damage the pre-impact condition of most fuel quantity system components could not be verified. Both fuel tank selectors were positioned to the lefthand tank, and it is probable that fuel starvation was the cause of the double engine failure. Company procedures for the Cessna 402 lacked a fuel quantity monitoring system to supplement fuel gauge indications. Dipping of the tanks was not a feasible option. Company pilots believed that the aircraft was fitted with low-fuel quantity warning lights, which was not the case. As three pilots believed the gauges indicated sufficient fuel was on board before the preceding round trip to the island, exhaustion may have followed an undetermined fuel indicating system malfunction. The failure of the company to require the use of operational flight logs, and other deficiencies in record keeping, were identified in the TAIC report. The much-publicised misunderstanding about the ditching location was not considered by the TAIC report to have affected the outcome of the rescue, but provides an example of the continued importance of using the phonetic alphabet in radiotelephony. A safety recommendation that operators use a fuel-quantity monitoring system to supplement fuel gauge indications was also made by the TAIC report.

It was determined that the loss of control after touchdown was the consequence of the captain's misuse of the thrust reverser during the landing roll and his confusion over crosswind conditions. Investigations revealed that after touchdown, the n°1 engine thrust reverser did not deploy because the n°1 engine power lever's position did not allow the reverser to be deployed. The following contributing factors were identified:
- Poor weather conditions,
- Cross wind component,
- Wet runway surface,
- Poor braking action.

The collision was due to the absence of visual detection of the other aircraft by each of the two crews in an uncontrolled Class G Airspace where collision avoidance relies exclusively on external vigilance ("See and Avoid" rule). The decision to change the flight regime and trajectory placed the crew of the Beech 1900D in an improvised and unusual flight situation with a public transport aircraft. The following contributing factors have been identified:
- The pilots, on different frequencies, were unaware of their mutual presence,
- The pilots had their attention focused on the ship 'Norway',
- The organization of the activity in the cockpit of the Beech 1900D and its ergonomics did not allow effective monitoring, particularly towards the outside of the turn,
- The dead angles of the Cessna 177 probably masked the Beech 1900D from its pilot while both aircraft were approaching each other,
- The position of the sun may have hampered the pilot of the Cessna 177,
- The Cessna 177 transponder was off, thus the aircraft could not be viewed on the ATC radar based in Lorient. As a result, he was unable to provide traffic information to the crew of the Beech 1900D.

After take off the aircraft pitched up uncontrollably, stalled fell to its right and crashed. The uncontrollable pitch up was caused by sudden uncommanded downward movement of the Trimmable Horizontal Stabilizer leading edge. This was due to partial detachment of its 'actuator forward bearing support' fitting due non installation of required hi-lok fasteners. Poor aircraft maintenance practices at Short Haul Operations Department contributed to the accident.

The following factors were identified:
- It was not possible to examine the debris of the aircraft to determine the contribution of this factor to the failure of the left engine.
- It is possible that the failure to carry out a type B2 inspection and/or to carry out a type A1 inspection by an unqualified person may have contributed to the occurrence of a low oil pressure emergency, due to material deterioration or inadequate services. The impossibility of examining the aircraft could not determine this aspect.
- The owner of the air taxi company participated due to lack of adequate supervision in the planning of operations, at the technical, operational and administrative levels. This deficiency can be characterized, among other things, by the owner of the company that allowed the aircraft to fly with the type B2 inspection expired; by the excessive amount of fuel, when refueling in Manaus; by the unreasonable number of people on board, causing the aircraft to fly with excess weight, and still, by the receipt of pilots' salary to be conditioned to the accomplishment of the fateful flight.
- Errors were made by the aircraft crew due to the improper use of the resources available in the cabin, intended for the operation of the aircraft, due to non-compliance with operational rules.
- There was a mistake made by the crew due to the inadequate preparation for the flight, assuming numerous failures, such as: the non conference, by the pilots, of the cargo and passengers manifest; the lack of the realization of a briefing and still, to accept an aircraft for a flight, being the same with its inspection not carried out.
- An error was made by the crew due to inadequate evaluation of certain aspects of the flight. Such deficiency was evidenced when the first sign of failure of the lubrication system occurred, after twenty minutes of flight, and even so, they decided to proceed with the flight, when the most sensible and safe would be the return, immediately, to Manaus.
- The airline's support staff participated in the planning of weight and balance of the aircraft and the number of passengers on board, providing incorrect information to the aircraft's crew members. In addition, the mechanic who performed the A1 type inspection was not qualified for the function.
- There has been intentional non-compliance by the crew members with the operational rules established by the aircraft manufacturer.
- The Commander did not foresee what was predictable, for lack of caution, thus intentionally increasing the risk margin of the mission.

Failure of the right engine for unknown reasons. Failure of the automatic propeller pitch control mechanism was a contributing factor.

Findings as to Causes and Contributing Factors:
- The crew did not realize that the pull to the left and the extended take-off run were due to the left brakes' dragging, which led to overheating of the brake components.
- Dragging of the left brakes was most probably caused by an unidentified pressure locking factor upstream of the brakes on take-off. The dragging caused overheating and leakage, probably at one of the piston seals that retain the brake hydraulic fluid.
- When hydraulic fluid leaked onto the hot brake components, the fluid caught fire and initiated an intense fire in the left nacelle, leading to failure of the main hydraulic system.
- When the L WING OVHT light went out, the overheating problem appeared corrected; however, the fire continued to burn.
- The crew never realized that all of the problems were associated with a fire in the wheel well, and they did not realize how serious the situation was.
- The left wing was weakened by the wing/engine fire and failed, rendering the aircraft uncontrollable.
Findings as to Risk:
- Numerous previous instances of brake overheating or fire on SA226 and SA227 aircraft had the potential for equally tragic consequences. Not all crews flying this type of aircraft are aware of its history of numerous brake overheating or fire problems.
- The aircraft flight manual and the emergency procedures checklist provide no information on the possibility of brake overheating, precautions to prevent brake overheating, the symptoms that could indicate brake problems, or actions to take if overheated brakes are suspected.
- More stringent fire-blocking requirements would have retarded combustion of the seats, reducing the fire risk to the aircraft occupants.
- A mixture of the two types of hydraulic fluid lowered the temperature at which the fluid would ignite, that is, below the flashpoint of pure MIL-H-83282 fluid.
- The aircraft maintenance manual indicated that the two hydraulic fluids were compatible but did not mention that mixing them would reduce the fire resistance of the fluid.
Other Findings:
- The master cylinders were not all of the same part number, resulting in complex linkage and master cylinder adjustments, complicated overall brake system functioning, and difficult troubleshooting of the braking system. However, there was no indication that this circumstance caused residual brake pressure.
- The latest recommended master cylinders are required to be used only with specific brake assembly part numbers, thereby simplifying adjustments, functioning, and troubleshooting.
- Although the emergency checklist for overheating in the wing required extending the landing gear, the crew did not do this because the wing overheat light went out before the crew initiated the checklist.
- The effect of the fire in the wheel well made it difficult to move the ailerons, but the exact cause of the difficulty was not determined.