KLM flight 433
| KLM flight 433 | |
|---|---|
 An identical Saab 340B from the KLM Cityhopper |
|
| Accident summary | |
| Accident type | Loss of control due to asymmetrical thrust |
| place | at Amsterdam Airport Schiphol , Netherlands
|
| date | April 4, 1994 |
| Fatalities | 3 |
| Survivors | 21st |
| Injured | 9 |
| Aircraft | |
| Aircraft type |
 Saab 340B
|
| operator |
KLM Cityhopper on behalf of KLM
|
| Mark |
PH-KSH
|
| Departure airport |
Amsterdam Schiphol Airport , Netherlands
|
| Destination airport |
Cardiff Airport , UK
|
| Passengers | 21st |
| crew | 3 |
| Lists of aviation accidents | |
The KLM flight 433 (Flight number: KL433 ) was a scheduled flight of the Dutch regional airline KLM Cityhopper from Amsterdam to Cardiff , who, however, under a flight number of the KLM was performed. The incident is also known as KLM Cityhopper Flight 433 . On April 4, 1994, a Saab 340B crashed during a failed return flight to Amsterdam Schiphol Airport . In the accident, which was essentially caused by a chain of pilot errors, three people were killed.
plane
The affected machine was a Saab 340B from Swedish production. The machine was finally assembled in 1990 and had the work number 340B-195. The aircraft completed its maiden flight on May 19, 1990 with the test registration number SE-F95 and was newly delivered to KLM Cityhopper on June 25, 1990 with the aircraft registration number PH-KSH and has been operated by KLM Cityhopper since then. The twin-engine regional transport aircraft was equipped with two turboprop engines of the type General Electric CT7-9B equipped.
Passengers and crew
There was a three-person crew on board, consisting of a flight captain, a first officer and a flight attendant. For the regional flight from Amsterdam Airport Schiphol to Cardiff Airport , 21 passengers were seated in the plane.
the accident
Shortly after take-off from Amsterdam Airport Schiphol , the warning lamp for the oil pressure of the right engine unexpectedly lit up. Even before the first officer took the checklist to hand, the master lowered the power of the right engine to idle.
The first officer read on the checklist that action is required if the warning system lights up and the oil pressure falls below 30 PSI. Since the reading showed a normal value, the pilots decided to continue flying.
When the machine reached an altitude of 17,000 feet (about 5200 meters), it stopped climbing. The pilots suspected a connection with the previously lit oil pressure warning and decided to turn around. The first officer radioed an emergency message to air traffic control in Schiphol.
The oil pressure finally actually dropped as a result of the idling into which engine No. 2 had been switched. When the aircraft was on its final approach to Schiphol, the pilots realized that it was flying too slowly. The captain decided to take off , retracted the landing gear and increased the thrust. The machine rolled excessively to the right. At a roll angle of 80 degrees, the right wing tip shortly after grazed a field next to the runway, whereupon the machine crashed.
Victim
The captain and two passengers were killed in the accident. Of the other people on board, 9 people were injured, while 12 were uninjured. The first officer could not remember the accident due to amnesia .
root cause
It turned out that the warning lamp had come on because of a short circuit in the switch. This was the only technical defect that had occurred on the aircraft, there were no problems with the engine oil pressure. The accident was caused by the subsequent pilot errors.
The master's first mistake, which resulted in the others, was reducing the thrust in engine number 2. This was possibly done intuitively, with the good intention of protecting the engine in the event that it should actually be defective - but it wasn't Measure that was provided for by some checklist.
After consulting the checklist as a result of the lighting up of the control lamp, the pilots decided to continue the flight. Nevertheless, the captain had not restored the thrust in the engine. The climb was therefore carried out with one engine.
At an altitude of 17,000 feet, the power limit of the first engine was reached. To continue the climb, the thrust in engine no. 2 would have to be restored. The problem could have been solved by simply turning on the thrust of the right engine. Instead, both pilots assumed a technical cause and therefore turned back.
The crash during the go-around attempt on the final approach occurred because the propeller blades of the engine, which was mistakenly believed to be defective, were not brought into the sail position. For a flight with only one engine, the propeller blades of the inactive engine were in a misalignment. The result was a strong thrust asymmetry: while the left engine pulled the engine forward due to the increase in thrust, the right engine generated increased air resistance, which also slowed the engine down. This eventually led to a loss of control and the machine crashing.
Media reception
The accident was filmed under the title Fatal Error Chain ( Fatal Approach ) in episode 5 of season 19 of Mayday - Alarm im Cockpit .
swell
- Aircraft accident report in the Aviation Safety Network
- Description of the accident and transcription of the cockpit voice recorder
- Operating history of the machine on airfleets.net
Coordinates: 52 ° 17 ′ 26.2 " N , 4 ° 44 ′ 59.3" E