Accident
On November 3, 1973, Pan Am Flight 160, a scheduled cargo flight operated by Pan American World Airways, departed John F. Kennedy International Airport in New York at 08:25 EST. The Boeing 707 was bound for Frankfurt, Germany, with a stop in Prestwick, Scotland, carrying 15,360 pounds (6,970 kg) of chemicals.
At 09:04 EST, the crew reported smoke in the lower 41 electrical compartment to air traffic control and indicated they would divert to Boston. ATC granted a return to JFK, but the cockpit soon became thick with smoke, prompting the crew to turn back toward Boston. To reduce weight for landing, the aircraft descended to 2,000 feet (610 m) to increase fuel burn. The crew requested and received approval to land on Runway 33 Left. They shut off all non-essential systems, and the transponder subsequently became inoperative.
During final approach, with the airplane properly configured, the yaw damper was disengaged due to critical errors in executing procedures, making control difficult at low speeds. Witnesses observed smoke pouring from the cockpit windows. The aircraft stalled and crashed in a near-vertical, nose-down attitude.
Cause
The accident resulted from several factors, including the continued generation of smoke in the cockpit. This smoke created an uncontrollable emergency, leading the crew to disable the yaw damper by turning off the essential bus. The smoke also impaired the crew's ability to perform tasks. Investigators could not identify the smoke's exact source but concluded it most likely originated from a nitric acid leak and improper packing of hazardous material, with a reaction between nitric acid and sawdust producing the smoke. Contributing factors included noncompliance with several laws governing hazardous material transportation, industry lack of knowledge, overlapping jurisdictions, and insufficient government surveillance.
Criminal Charge
Pan American World Airways was indicted on a charge of criminal negligence related to the crash, pleading no contest in 1976. The company that owned the chemicals and other firms involved in the shipment were also charged. This marked the first time an airline had been charged with criminal negligence in connection with a plane crash.