Predicting pilot-error incidents of US airline pilots using logistic regression.

In a population of 70,164 airline pilots obtained from the Federal Aviation Administration, 475 males and 22 females had pilot-error incidents in the years 1986-1992. A simple chi-squared test revealed that female pilots employed by major airlines had a significantly greater likelihood of pilot-error incidents than their male colleagues. In order to control for age, experience (total flying hours), risk exposure (recent flying hours) and employer (major/non-major airline) simultaneously, the author built a model of male pilot-error incidents using logistic regression. The regression analysis indicated that youth, inexperience and non-major airline employer were independent contributors to the increased risk of pilot-error incidents. The results also provide further support to the literature that pilot performance does not differ significantly between male and female airline pilots.

Policy improvements for prevention of alcohol misuse by airline pilots.

Alcohol abuse by airline pilots poses a potential danger to the safety and welfare of the flying public. This paper analyzes two strategies for reducing pilot-error aviation accidents: conducting background checks on pilots for driving-while-intoxicated (DWI) convictions and random preflight alcohol testing of airline pilots. Although both policies have been implemented, no empirical research had previously been conducted to justify either strategy. The results and conclusions of this study are based on analysis of data obtained from the Federal Aviation Administration on the flying performance of 70164 airline pilots. DWI convictions were found to be associated with a significantly greater risk of a pilot-error accident. In contrast, no evidence was found to validate the assumption that a random alcohol testing program could have prevented accidents. The results provide support for improving the existing DWI background check program and for reducing the sampling rate of random alcohol testing for airline pilots. This twofold strategy could result in greater improvements in aviation safety and reduced overall costs.

Evidence for short or ultrashort loop negative feedback of gonadotropin-releasing hormone secretion.

The present studies tested the hypothesis that either short or ultrashort loop negative feedback regulation of gonadotropin-releasing hormone (GnRH) secretion occurs in the ewe. As part of ongoing studies investigating the regulation of follicle-stimulating-hormone secretion, we obtained the unexpected result that a GnRH antagonist (Nal-Glu) may stimulate GnRH secretion. In that experiment, hypophyseal portal blood was collected from five short-term ovariectomized ewes at 5-min intervals for 6 h before and 6 h after intravenous injection of Nal-Glu (10 micrograms/kg body weight). An increase in GnRH pulse frequency in association with the blockade of luteinizing hormone (LH) release was evident in 3 of the 5 animals. To determine if an effect of Nal-Glu on episodic GnRH secretion would be more evident in an animal model in which low-frequency pulses of GnRH prevail, the study was repeated in six ewes in the midluteal phase of the estrous cycle and six ovariectomized ewes bearing estradiol and progesterone implants to suppress GnRH release (artificial luteal model). In luteal-phase ewes, administration of Nal-Glu was followed by an increase in GnRH pulse frequency, pulse size and the secretion of GnRH between pulses, and by a blockade of LH release. In ovariectomized ewes treated with estradiol and progesterone, Nal-Glu administration also stimulated GnRH and inhibited LH secretion. Our finding that the GnRH antagonist stimulated GnRH secretion is consistent with the hypothesis that endogenous GnRH may influence its own release via either a short or ultrashort loop feedback mechanism.