The Deadliest Plane Crash looks back at the crucial four hours before the disaster, when an improbable chain of coincidences, bad luck, and misjudgments snowballed into tragedy. The situation sounds eerily current. It all began with a terrorist bomb threat to the airport on Gran Canaria Island that diverted air traffic to Tenerife. The small Tenerife airport was soon overcrowded while, even as its control tower was understaffed. Thick fog rolled in and destroyed visibility as the KLM plane loaded up a full tank of fuel. A series of unclear communications and time pressure on the Dutch crew ultimately contributed to the KLM captain’s fatal error — one that violated the fundamental rules of aviation and baffled expert investigators for decades afterwards.

NOVA’s film reassesses the evidence and conclusions of the official accident investigations of by the Spanish and Dutch authorities. It features gripping first-hand testimony personal storiesrecollections from Pan Am co-pilot Robert Bragg, flight attendant Joan Jackson, and passengers who somehow fought their way out of the blazing, disintegrating Pan Am 747.

NOVA also investigates the improvements in runway safety that have been made in the three decades following the Tenerife crash. Disturbingly, runway incursions in the U.S. are still an everyday event: about 325 of them occur each year. (The FAA defines runway incursions as “any occurrence in the airport runway environment involving an aircraft, vehicle, person, or object on the ground that creates a collision hazard or results in a loss of required separation with an aircraft taking off, intending to take off, landing, or intending to land.”)