*Article* **Aircraft-Assisted Pilot Suicides in the General Aviation Increased for One-Year Period after 11 September 2001 Attack in the United States**

**Alpo Vuorio 1,2,\*,†, Tanja Laukkala 3,†, Ilkka Junttila 4, Robert Bor 5,6, Bruce Budowle 7, Eero Pukkala 8, Pooshan Navathe 9 and Antti Sajantila 2**


Received: 13 September 2018; Accepted: 6 November 2018; Published: 12 November 2018

**Abstract:** Pilot aircraft-assisted suicides (AAS) are rare, and there is limited understanding of copyca<sup>t</sup> phenomenon among aviators. The aim of this study was to evaluate the possible effect the 11 September 2001, terrorist attacks had on pilot AASs in the U.S. Fatal aviation accidents in the National Transportation Safety Board (NTSB) database were searched using the following search words: "suicide", "murder-suicide" and "homicide-suicide". The timeline between 11 September 1996, and 11 September 2004, was analyzed. Only those accidents in which NTSB judged that the cause of the accident was suicide were included in the final analysis. The relative risk (RR) of the pilot AASs in all fatal accidents in the U.S. was calculated in order to compare the one, two, and three-year periods after the September 11 terrorist attacks with five years preceding the event. The RR of a fatal general aviation aircraft accident being due to pilot suicide was 3.68-fold (95% confidence interval 1.04–12.98) during the first year after 11 September 2001, but there was not a statistically significant increase in the later years. This study showed an association, albeit not determinate causal effect, of a very specific series of simultaneous terrorist murder-suicides with subsequent pilot AASs.

**Keywords:** September 11 terrorist attacks; pilot aircraft-assisted suicide; copyca<sup>t</sup> effect
