The Shell Model Analysis of British Airways Flight 5390

The SHELL Model Analysis of British Airways Flight 5390

Abstract

Human error in aircraft maintenance and inspection has been a factor in many air carrier accidents. Whenever humans are involved in an activity, human error is a certain sequel. To demonstrate the relevance of Human Factors in aviation safety, this analysis will utilize SHELL model where each of its components will be examined using the following interpretations: liveware (human), hardware (machine), software (procedures, symbology, etc.) and environment (the conditions in which the liveware functions).

On 10 June 1990, a BAC 1-11 aircraft departed Birmingham International Airport for Malaga, Spain, with 81 passengers, four cabin and two flight crew. As the aircraft was climbing through 17 300 feet pressure altitude, the cockpit windscreen had blown out and the pilot-in-command was partially sucked out. The investigation revealed that the accident occurred because a replacement windscreen had been fitted with the wrong bolts. However, this maintenance error is not a product of a sole factor but a result of a continuous breakdown in the system's safety net.

Liveware is at the center of the model. Human is generally considered the most critical component in the system as it is subjected to considerable variations in performance and many limitations. The assignment of changing the aircraft windscreen was undertaken by one technician who has not performed such task in two years, but who was fully responsible for the work carried out. Unfortunately due to various external factors, the work he produced unfolded inadequate care, poor work practices, failure to adhere to company standards and failure to use suitable equipment.

Liveware-Hardware refers to the human-machine interaction. In the case of the Flight 5390, the liveware-hardware mismatch transpired due to failure to use suitable equipment. The difference between the correct bolts and the bolts installed was minimal, only 200th of an inch,...