On March 27th 1977, the biggest accident in airline history took place (at least if we leave the attack on the Twin Towers out of the equation).

The accident happened due to a concurrence of circumstances and an accumulation of human errors escalating to a disastrous 583 casualties.

A few of those circumstances and/or causes were:

• Stressors: fog and drizzle (limited sight of 1000 to 3000 feet), pilots were stressed out because both Boeing 747’s were (inconveniently) diverted to Tenerife instead of their original destination, Las Palmas. They couldn’t go there because of a bomb alarm, causing serious delays.
• Human error: due to the limited vision, the PanAm reaches the junction too late causing them to remain on the runway (too long).
• Technical problems: part of the lighting (center line) wasn’t ready yet and they were experiencing radio interference.
  Authority: the KLM captain was (internationally) known for being ‘the exemplary pilot’ of KLM. He was a pilot and a flight instructor at the same time and KLM used him in advertising. They referred to him as Mr. KLM. Although his colleagues were uncertain about the position of the PanAm, they wouldn’t question his authority.

This story proves that a lot can go fundamentally wrong due to a couple of “human errors”. In order to reduce the risk on errors, making an overview of all possible “risk factors” and taking precautionary measures where possible (some factors are hard to prevent) is a good start. FMEA is a very know method originating from the automotive industry. On the other hand, FMEA doesn’t really consider human errors.

If you’re interested in some more background information about this accident, you can find a lot of opinions, details and multimedia on http://www.project-tenerife.com/