Causal Factors

(top ten updated - correct to end Q3, 2007)

	2004	2005	2006	Q1, Q2 & Q3 2007
Correct pilot readback followed by incorrect action	19.7%	23.1%	22.9%	26.6%
Failure to follow ATC instruction	3.7%	7.6%	9.7%	9.1%
Failed to follow cleared SID	8.4%	10.3%	10%	6.7%
Altimeter setting error	9.6%	7.3%	7.1%	5.5%
Mis Hear	5.2%	4.9%	6.8%	5.3%
Incorrect pilot readback by correct aircraft	8.6%	6.1%	4.3%	4.9%
Pilot readback by incorrect aircraft	7.4%	5.9%	3%	3.4%
Aircraft technical problem	5.7%	2.9%	2.6%	3.2%
Not Hear	3.9%	2.5%	1.5%	2.8%
Poor FMS Handling	5.7%	2.9%	2%	2.6%

Move your mouse over each causal factor above for an explanation.

By far and away the biggest causal factor is still ‘correct pilot readback followed by incorrect action’. ‘Altimeter setting error’ and ‘failure to follow the SID’ also remain very high.

Causal Factors as a PDF file

Event Factors of Level Busts since 2006

click on graphs below for larger version

Event Factors 2006

Source: NATS Division of Safety

Event Factors 2007

Source: NATS Division of Safety

Event Factors 2008 (to end of October)

Source: NATS Division of Safety

These graphs were updated in October 2008