Date: November 3rd, 1973
Type: Boeing 707-321C
Registration: N458PA
Operator: Pan American World Airways
Where: Boston, MA (USA)
Report No.: (NTSB-AAR-74-16)
Report Date: -
Pages: -

This is not an accident investigation report.

The Boeing lost control and crashed on approach to Boston-Logan Runway 33. The aircraft had diverted to Boston due to the cockpit being filled with smoke. PROBABLE CAUSE: "The presence of smoke in the cockpit which was continuously generated and uncontrollable. The smoke led to an emergency situation that culminated in loss of control of the aircraft during final approach, when the crew in uncoordinated action deactivated the yaw damper in conjunction with incompatible positioning of flight spoilers and wing flaps. The NTSB further determines that the dense smoke in the cockpit seriously impaired the flightcrew's vision and ability to function effectively during the emergency. Although the source of the smoke could not be established conclusively, the NTSB believes that the spontaneous chemical reaction between leaking acid, improperly packaged and stowed, and the improper sawdust packing surrounding the acid's package initiated the accident sequence. A contributing factor was the general lack of compliance with existing regulations governing the transportation of hazardous materials which resulted from the complexity of the regulations, the industrywide lack of familiarity with the regulations and the working level, the over-lapping jurisdictions, and the inadequacy of government surveillance." (NTSB-AAR-74 -16)