Swissair Flight 306
| Industry | Airline |
|---|---|
| Headquarters | Zurich , Switzerland |
Swissair Flight 306, operated by a Sud Aviation SE-210 Caravelle III bearing the name Schaffhausen, was conducting a scheduled international service from Zurich to Rome, with a stopover in Geneva. On 4 September 1963, shortly after takeoff, the aircraft crashed near Dürrenäsch, Aargau, resulting in the fatalities of all 80 individuals aboard.
Timeline
On the morning of the accident, Zurich Airport was shrouded in thick fog. At 06:04 UTC, the plane began taxiing toward runway 34, following an escort vehicle. The flight crew communicated at 06:05 that they intended to taxi halfway down runway 34 to evaluate the fog conditions, utilizing high engine thrust to help clear the fog. By 06:12, the aircraft had returned to runway 34 and took off at 06:13, ascending toward its assigned cruising altitude of flight level 150 (approximately ).
Witnesses reported seeing white smoke emanating from the left side about four minutes after liftoff, followed by visible flames on the left wing. At around 06:20, near , the plane initiated a descent while executing a gentle left turn before entering a steep dive.
A Mayday distress signal was transmitted at 06:21. The aircraft impacted near Dürrenäsch, approximately from Zurich Airport, at 06:22.
Probable cause
The investigation determined that overheating brakes during taxiing—caused by applying full engine power—led to failure of the magnesium wheels, with one wheel disintegrating on the runway prior to departure. When the landing gear was retracted, hydraulic lines within the gear bay were compromised, likely damaged by fragments from the exploded wheels or rims during ascent. Leaked hydraulic fluid ignited upon contact with the overheated landing gear rims, causing fire damage to both the gear bay and wing structure. Analysis of flight recorder data and absence of further radio communication from the crew indicate that problems started at 06:18, with electrical malfunctions appearing two minutes later as fire progressively weakened structural components. The left engine had ceased operation before impact; however, it remains unclear whether this was due to crew intervention or fire damage. The exact cause of the loss of control could not be definitively established but may have involved fire damage affecting the left wing, rear fuselage, hydraulic flight control systems, or elevator controls.
Result
In response to this tragedy, all Caravelle aircraft were retrofitted to utilize hydraulic fluids that are non-flammable.
Casualties and aftermath
Among those on board were 74 Swiss citizens, two Americans (including one with dual Iranian citizenship), one British national, one Egyptian (notably Olympic rower Ibrahim Abdulhalim), one Israeli passenger, and an individual from either Belgium or Austria.
The disaster had a profound impact on the village of Humlikon, Canton of Zurich: 43 residents—constituting about 20% of its population—were passengers en route to a farm testing site near Geneva. The calamity claimed the entire local government council, school board members, and the post office clerk. Orphaned children were cared for by relatives; six required relocation mainly within nearby communities.
Despite setbacks in farm operations, assistance poured in from neighboring villages and further afield. Volunteers included apprentices, students, firefighters, soldiers, scouts, railway workers, police officers, and international aid personnel. Manual labor was employed to harvest roughly 600 tons of potatoes; corn crops were threshed and new seeds planted according to schedule. A little over one month later, elections were held for a new local council among remaining eligible voters.
See also
- Nigeria Airways Flight 2120 – 1991 accident resulting from a fire in the landing gear
- Air France Flight 4590 – 2000 disaster caused by an in-flight fire initiated by a tire blowout during takeoff
- Swissair Flight 111 – incident involving an in-flight fire on a Swissair flight
- Mexicana Flight 940 – 1986 crash linked to landing gear fire
- Propair Flight 420 – 1998 accident related to landing gear fire