Nordeste Linhas Aéreas Flight 115

On 11 November 1991, an Embraer EMB 110 crashed on the domestic scheduled flight Nordeste Linhas Aéreas Flight 115 from Recife to Salvador, killing all 15 occupants and 2 people on the ground.

Sequence of events

While the EMB 110 was accelerating on the runway, an uncontained failure of the right engine occurred, after which a fire broke out. The takeoff was nevertheless continued and the aircraft rotated at 900 m instead of the usual 570 m. It climbed only slowly and there was another bang, after which parts detached from the burning engine, fell down and set a small area within the fenced airport grounds on fire. The aircraft reached a height of 30 m and then yawed to the right. After that it grazed 2 houses, crashed at 21:43, 30 s after liftoff, onto a public square and then exploded.

Accident investigation

The accident investigation was made more difficult by the fact that the aircraft had no flight recorders.

The investigations found that in the right engine a busbar of a sensor responsible for the temperature indication was inadequately secured and insulated, which is why parts of the insulation came loose. This had the consequence, on the one hand, that too low a temperature was indicated and, on the other hand, that the cooling holes of the so-called CT vane ring, on which the compressor turbine depended, became clogged. Because of this, the right engine operated for some time at an elevated temperature. In addition, due to a faulty casting the vanes had wall thicknesses that deviated from those in the design. Owing to these factors, cracks developed in the ring over time and ultimately the engine failure occurred when it failed.

According to the investigation, the pilots could have, and should have, aborted the takeoff. Although it could not be confirmed because of the lack of flight recorders, the rudder was possibly trimmed in the wrong direction (towards that of the failed engine). This would have happened either before takeoff or after the engine failure. Simulator flights at Embraer in any case showed that with correct trim a shallow climb would have been possible, whereas with incorrect trim continued flight was not possible. The night may also have adversely affected the pilots' behaviour, which is why they continued the takeoff.

Several serious deficiencies were found at the airline. It had no training programme and did not let the pilots train on the flight simulator, which would have prepared them for emergencies. The instructor had the same level of knowledge as the trainees. Maintenance was also deficient; there had been a total of 3 “Hot Section Inspections” (HSI) on the right engine of the crashed aircraft. In all of them the cracks on the CT vane ring were found. The maintenance manual stated that above a certain degree of material wear the entire vane assembly had to be replaced. Despite the cracks and an operating time of 1,250 hours, the ring was not replaced and was released for a further 1,250 hours of operation. This deviation from procedure had been neither supervised nor checked by the maintenance inspector. There was a signature from the maintenance engineer only for the 1st and 3rd HSI, while there was none from the inspector for any of the HSIs. The airline had also not properly supervised any of this.