Distinct Small Errors Can Become Linked and Amplified into a Big Tragedy
On 27-March-1977, two fully loaded Boeing 747 passenger jets operated by Pan American World Airways (Pan Am) and KLM Royal Dutch Airlines collided on the runway, killing 583 passengers and crew on the two airplanes. Only 61 survived—all from the Pan Am jet, including its pilot.
These two flights, and a few others, were diverted to Tenerife after a bomb went off at the Gran Canaria Airport in Las Palmas, their original destination. Tenerife was not a major airport—it had a single runway, and taxi and parking space were limited. After the Las Palmas airport reopened, flights were cleared for takeoff from Tenerife, but the fog rolled in over Tenerife reducing visibility to less than 300 feet. Several airplanes that had been diverted to Tenerife had blocked the taxiway and the parking ramp. Therefore, the KLM and Pan Am jets taxied down the single runway in preparation for takeoff, the Pan Am behind the KLM.
At one end of the runway, the KLM jet turned 180 degrees into position for takeoff. In the meantime, the Pan Am jet was still taxiing on the runway, having missed its taxiway turnoff in the fog. The KLM pilot jumped the gun and started his take-off roll before he got clearance from traffic control.
When the pilots of the two jets caught sight of each other’s airplanes through the fog, it was too late for the Pan Am jet to clear out of the runway into the grass and for KLM jet to abort the takeoff. The KLM pilot lifted his airplane off the runway prematurely, but could not avoid barreling into the Pan Am’s fuselage at 240 kmph. Both the jets exploded into flames.
The accident was blamed on miscommunication—breakdown of coordinated action, vague language from the control tower, the KLM pilot’s impatience to takeoff without clearance, and the distorted cross-talk of the KLM and Pan Am pilots and the controllers on a common radio channel.
Breakdown of Coordination Under Stress
Sweeping changes were made to international airline regulations following the accident: cockpit procedures were changed, standard phrases were introduced, and English was emphasized as a common working language.
The surviving passengers’ first- and second-hand accounts recall the horror of those passengers on the right side of the Pan Am jet who saw the lights of the speeding KLM 747, just as the Pan Am pilot was hastily turning his airplane onto the grass to avoid the collision.
Ziomek describes how passengers escaped. Some had to make the difficult choice of leaving loved ones or friends and strangers behind.
Dorothy Kelly … then spotted Captain Grubbs lying near the fuselage. Badly burned and shaken by his jump from the plane, he could not move. “What have I done to these people?” he yelled, pounding the ground in anguish. Kelly grabbed him under his shoulders and urged “Crawl, Captain, crawl!”
Recommendation: Read Jon Ziomek’s Collision on Tenerife
Some of the bewildering details make for difficult reading—especially the psychological effects (post-traumatic stress syndrome) on the surviving passengers. But Jon Ziomek’s Collision on Tenerife is important reading, providing a comprehensive picture of the extensive coordination required in aviation, the importance of safety and protocols, and how some humans can freeze in shock while others spring into action.
The key takeaway is the recognition of how small errors and problems (an “error chain”) can quickly become linked and amplified into disastrous outcomes.