Brazil

On final approach in limited visibility due to poor weather conditions, the pilot-in-command lost control of the airplane after suffering a spatial disorientation.

The exact cause of the accident could not be determined with certainty. However, the following findings were reported:
- a. Human Factor
(1) Undetermined Physiological Aspect
Given the characteristics of the accident, which resulted in the destruction of the bodies, making it impossible to carry out examinations, it cannot be specified whether it contributed or not. However one cannot rule out the possibility that one of the crew members has been affected by a sudden illness (2nd Hypothesis of the Analysis).
(2) Psychological Aspect - Undetermined
It may have influenced, to the extent that the commander was operating an aircraft in which he had little experience and little knowledge, and which was demonstrated by the insecurity in the operation, reported to other pilots.
b. Material Factor
(1) Design Deficiency - Undetermined
Despite the information provided by representatives of Learjet Corp. who participated in the investigations, that the compensator engine ('pitch trim') with which this aircraft was equipped, had already undergone the modifications determined by the Federal Aviation Administration (FAA), one cannot help but wonder about a possible firing and locking of the 'pitch trim' engine in the extreme position (3rd Hypothesis of the Analysis). This aspect was hampered as the destruction suffered by the aircraft made a detailed analysis of the pitch trim system impossible.
c. Operational Factor
(1) Disabled Instruction - Contributed.
The commander and the co-pilot received a less than desired instruction, in quantitative and qualitative terms. As a result, the pilots did not acquire the full technical conditions necessary for the proper operation of the aircraft. The failure to perform the standard procedure to be followed in the emergency that led to the accident, i.e. the lowering of the landing gear, attests to the poor instruction given.
(2) Deficient Application of Controls: - Contributed
The pilots did not adjust the engine power properly after leveling and, after the aircraft started to abruptly descend, as a result, the 'overspeed' occurred, they could not avoid the loss of control.
(3) Weak Cockpit Coordination - Contributed.
The pilots made inadequate use of the aircraft's resources for its operation.
(4) Forgetfulness - Contributed.
This aspect is in accordance with the previous one, since the lowering of the undercarriage is part of the standard procedure to be performed in cases of overspeed.
(5) Little Flight Experience in the Aircraft - Contributed
The captain, despite having 6,500 hours of flight time, had already intended to fly another jet plane, but had flown little on Learjet. The other pilot, in turn, had had less experience in jet flying as a co-pilot, and in the Learjet, specifically, flew less than the commander.
As a result, when they were faced with an emergency that required rapid identification in order to take the necessary measures to remedy it, they lacked the necessary experience.
(6) Deficient Supervisor - contributed.
The air taxi company, to which the pilots belonged, was in a hurry to train this new crew. This resulted in inadequate operational training for the pilots, which demonstrates poor supervision of the company. The Civil Aviation System, through the regional body that deals directly with general aviation, failed to carry out proper oversight, as it did not detect the errors in the statements of instruction, and allowed the checks of the captain and the co-pilot to be carried out without reaching the minimum amount of flight hours and landings on that aircraft.

The following findings were reported:
a. Human Factor
(1) Physiological Aspect
- There was no evidence of this aspect contributing to the occurrence of the accident.
(2) Psychological Aspect - Contributed
- The psychological aspect contributed through the generation of a high level of anxiety to perform the landing and in the diversion of the focus of attention during the approach manoeuvres to land.
- The psychological aspect was influenced by the activation of the smoke alarm which generated an increase in the workload on board.
b. Material Factor
- There were no indications that this factor contributed to the accident.
c. Operational Factor
(1) Deficient Instruction
- Although the instruction was carried out in accordance with what the standards recommend, the failures that contributed to the accident are characteristic of lack of experience in facing abnormalities simultaneously with the maintenance of flight control. Such failures could be avoided with more adequate simulator instructions and training involving the cockpit management aspects.
(2) Poor Maintenance - Undetermined .
- It was not possible to determine the cause of the activation of the 'Aft Cargo Smoke' alarm and whether the maintenance services contributed to this occurrence.
(3) Deficient Cockpit Coordination
- Inadequate performance of the duties assigned to each crew member. The procedures foreseen for the execution of descent by instrument have been modified and some have been deleted depending on the appearance of a complicator element (smoke alarm).
(4) Influence of the environment
- The dark night contributed to the creation of the 'black hole' phenomenon, or 'background figure', making it difficult to perceive external references for a possible identification of the vertical distance of the aircraft from the ground.
(5) Deficient Oversight
- The supervision, at cockpit level, contributed to the accident by the inadequate management of the resources available for the flight in the cockpit.
- Company level supervision contributed to the accident by not identifying the need for cockpit management training and providing it to the crew involved.
- Supervision, at company level, was also inadequate when climbing to the same mission, two pilots unfamiliar with the airplane to be used and in night operation.
(6) Other Operational Aspects
- The failure to comply with several 'Callouts', the non-use of the radio altimeter and the inadequate use of the 'altitude alert', as an aid to the accomplishment of the descent procedure, contributed to the occurrence of the accident.

At the time of impact, both engines were running at cruise power. On takeoff from Brasília Airport, the total weight ot the aircraft was 436 kilos above MTOW, which may contribute to the accident. Nevertheless, investigations were unable to determine the exact cause of the accident. Maybe the pilot-in-command made a brutal movement on the control column, causing the aircraft to become uncontrollable following a structural failure of both winglets that were recently installed.

Wrong approach configuration on part of the crew who continued the descent below MDA of 5,000 feet in limited visibility. The following contributing factors were reported:
- Poor judgment on part of the crew,
- Lack of crew coordination,
- Poor approach planning,
- The crew failed to follow the published approach procedures,
- Lack of visibility due to low clouds (Mt Taquari was shrouded in clouds),
- The crew did not establish any visual contact with the runway,
- Deficiencies in crew management, recruiting, selection and training supervision.

Controlled flight into terrain after the crew decided to continue the descent under VFR mode in IMC conditions. It was reported that the wrong approach configuration adopted by the crew caused the aircraft to enter a valley which was not mentioned on approach charts. Due to poor visibility because of low clouds, the crew was unable to distinguish the mountain struck by the aircraft. The crew was misled by external factors inherent to weather conditions.

The accident was the consequence of the failure of the right engine during takeoff. It was determined that the temperature indicator for the right engine was faulty, displaying a lower than actual temperature. The engine operated for some time at high temperatures because of the faulty system. It was also found that, after completion, some maintenance and inspection tasks were just signed by the maintenance engineer. Signatures from the maintenance inspector were missing.
The following contributing factors were reported:
- Poor crew reaction to an emergency situation,
- Poor maintenance,
- Manufacturing deficiency,
- The crew failed to abort the takeoff procedure.