History of Air Accident Investigation

International Civil Aviation Organisation

The procedures for air accident investigations were first laid down in 1928 by the US National Advisory Committee for Aeronautics. They required air accident investigators to consider the immediate and underlying factors of an accident in order to establish and apportion blame for its occurrence. A credit system was put in place that weighted causal factors according to their overall culpability – for example, an accident could be regarded 70% the result of pilot error and 30% the result of environmental factors. (Ames,1928).
In 1944 the Chicago Convention drafted a set of procedures and processes to govern the burgeoning international civil aviation industry.
Wright Flyer

Wright Flyer at Forty Myer, 3 September 1908. © NASA, sourced from Wikimedia Commons.

Included in these procedures were rules concerning the responsibilities of contracting states in the event of an aviation accident on their soil. These standards and recommended practices were developed by the Accident Investigation Division between February 1946 and February 1947, and were later designated as Annex 13 of the convention.  The convention allowed states to generate their own rules for accident investigation, so long as the core practices of Annex 13 were incorporated and investigative practices aligned with ICAO Doc 9620, the Manual of Aircraft Accident Investigation.
The primary focus of Annex 13 differed from that of the US National Advisory Committee for Aeronautics in 1928: it was no longer to find fault and apportion blame for an aircraft accident, but to provide a mechanism by which participants in the industry - pilots, aircraft manufacturers and regulatory agencies – could learn from their mistakes.
It was under the oversight of Annex 13 that the investigation into the Erebus disaster took place.