The aircraft took off from Amsterdam at 12:19 pm, with Captain Gerrit Lievaart as the pilot flying. Eleven minutes after takeoff, at 12:30 pm, the pilots received a low oil pressure warning on the No.2 engine. Then, before consulting the relevant checklist, the captain unilaterally set that engine's power to idle, probably to reduce the risk of damage. However, the oil pressure gauge was still showing above 50 PSI, indicating that the warning was false. As the relevant checklist recommended continuing the flight under the circumstances, the pilots did not return to Schiphol or divert. However, the captain did not return the engine to the previous throttle setting, leaving the aircraft effectively flying on one engine. As the Saab reached flight level 170, the loss of power prevented the aircraft from climbing further. The crew misinterpreted this as confirmation that the right engine was faulty, and made a Pan-Pan call, requesting to return to Schiphol Airport. On final approach, at a height of 90 feet, the captain decided to perform a go-around, as the plane's airspeed was not sufficient for landing. He commanded full throttle to the left engine, but did not touch the right, which was still at idle. As a result of the thrust imbalance, the aircraft rolled to the right, pitched up, stalled, and hit the ground at 80 degrees of bank. Of the 24 people on board, 3 were killed - the captain and 2 passengers. Out of the 21 survivors, 9 suffered serious injuries, including the first officer. Due to amnesia caused by the crash, the first officer could not recall the accident.
Aircraft and crew
The aircraft involved was a Saab 340, registration PH-KSH, which had first flown in 1990. The aircraft was powered by two General Electric CT7-9B turboshaft engines and had flown 6,558 hours at the time of the accident. The captain, 37-year-old Gerrit Lievaart, had been with KLM Cityhopper since 2 March 1992. He had a total of 2,605 hours flying time, including 1,214 hours on a Saab 340. However, training records revealed that he had failed two engine-out checks, and on his most recent one had been given a “standard minus,” the lowest passing grade. The first officer, 34-year old Paul Stassen, had been with KLM Cityhopper since 27 January 1992. He had a total of 1,718 hours flying time, including 1,334 hours on a Saab 340.
Accident investigation
The final report from the Netherlands Aviation Safety Board found that pilot error, through inadequate use of flight controls during unequal throttle go-around, resulting in loss of control, was the primary cause of the accident. In addition, the report included recommendations directed at KLM, regarding contributing factors, addressing: improved training on Crew Resource Management; improved pilot assessment techniques; and improved guidance on flying with an idle engine. In addition, the report found that the crash was generally survivable, with the Captain's death attributable to not wearing his shoulder restraints.
The crash of KLM Cityhopper Flight 433 was covered in 2019 in "Fatal Approach", a Season 19 episode of the internationally syndicated Canadian TV documentary series Mayday.
