Swissair Flight 306

Swissair Flight 306
	Crash site of SR 306 near Dürrenäsch
Accident
Date	September 4, 1963
Summary	In-flight fire leading to hydraulic failure and loss of control
Site	near Dürrenäsch, Switzerland ; 47°19′N 8°09′E
Aircraft
Aircraft type	Sud Aviation SE-210 Caravelle III
Aircraft name	Schaffhausen
Operator	Swissair
Registration	HB-ICV
Flight origin	Zurich Airport
Stopover	Geneva International Airport
Destination	Fiumicino Airport
Passengers	74
Crew	6
Fatalities	80
Survivors	0

Swissair Flight SR306, a Sud Aviation SE-210 Caravelle III, named Schaffhausen, was a scheduled international flight from Zürich to Rome, via Geneva. It crashed near Dürrenäsch, Aargau, on September 4, 1963, shortly after take-off, killing all 80 people on board.[1]

Timeline

Swissair's HB-ICX, sister aircraft to the aircraft HB-ICV lost in the accident.

Zurich Airport was in dense fog when the plane was due to take off at 06:00 UTC. At 06:04 the flight was allowed to taxi to runway 34 behind an escorting vehicle. At 06:05 the crew reported that they would taxi halfway down runway 34 to inspect the fog and then return to the take off point. This was done using high engine power in order to disperse the fog. Around 06:12 the aircraft returned to runway 34 and was allowed to take off, which it did 06:13, and started to climb to flight level 150, its cruising height.

Four minutes later people on the ground noticed a white trail of smoke coming from the left side of the aircraft. Shortly after, a long flame erupted from the left wing. Around 06:20 the aircraft reached a height of about 2700 m. It then began to descend, entering a gentle left turn before losing height more quickly. It then went into a final, steep dive.

At 06:21 a MAYDAY message was issued. At 06:22 the aircraft crashed into the ground on the outskirts of Dürrenäsch, approximately 35 km from Zürich Airport.[2]

Probable cause

The aircraft's brakes overheated due to the application of full engine power during taxiing. This caused the magnesium wheels to burst, one of them on the runway prior to departure. Upon retraction of the landing gear, the hydraulic lines in the gear bay were damaged. This was caused either by the wheels that had exploded, or the bursting of the other wheel rims during the climb. Subsequently, spilled hydraulic fluid ignited when it came in contact with the overheated landing gear rims. The fire damaged the gear bay, followed by the wing. Finally losing its hydraulic pressure, the aircraft became impossible to control. The cabin and the cockpit were filled with smoke, adding to the predicament of the crew. Control of the aircraft was lost totally at around 06:18, and the ensuing final dive and impact destroyed the aircraft.[1]

Result

As a result of this accident, all Caravelles were modified to use non-flammable hydraulic fluids.[2]

Casualties and aftermath

This crash severely affected the small village of Humlikon in the Canton of Zürich: 43 of its 217 citizens (20% of the population) had boarded the plane to visit a farm test site near Geneva. Among those who perished were the entire local council, all members of the local school board, and the village's post office clerk. A number of children who were orphaned were looked after at home by relatives, and six of these children had to move, all but one of whom went to live with relatives nearby. There were 74 Swiss nationals on board as well as two Americans (one dual citizenship with Iran), one Briton, one Egyptian, one Israeli, and one passenger either from Belgium or Austria.[3][4]

Further problems arose with the upkeep of the local farms, but people from the nearby villages helped. Apprentices came from local firms, students, firemen, soldiers, boy scouts, railroad workers and policemen, as well as volunteer school children, and even from abroad to help. Approximately 600 tons of potatoes were harvested manually, corn was threshed and the new crop seeds were sown in time. Just over a month after the crash, a new council was elected by the 52 remaining eligible voters.[5]

References

"Swissair 306 air crash". Pilotfriend.com. Retrieved 2 January 2013.
"Swissair HB-ICV – 4. September 1963". Sud Aviation. Retrieved 2 January 2013.
"Jornal do Brasil (RJ) - 1960 a 1969 - DocReader Web". memoria.bn.br. Retrieved Mar 25, 2019.
http://www.humlikon.net/geschichte/liste-schweiz.htm
"Der Flugzeugabsturz in Dürrenäsch 1963" (in German). Humlikon.net. Archived from the original on 17 July 2012. Retrieved 2 January 2013.