Search

Introduction: Radio communication remains important for the delivery of safety-critical information in military aviation. Pilots are exposed to high noise levels. Noise attenuation provided by certain helmets is not sufficient, and resulting noise exposure can deteriorate operational effectiveness and flight safety. A need for hearing protection that enables efficient communication is obvious, especially for fighter and helicopter pilots. One possible solution for this issue is molded communication earplugs (m-CEP). Data about the advantages and disadvantages of m-CEPs are limited., Methods: To determine the usage rates, advantages, disadvantages and pilot opinions about m-CEPs, an anonymous survey study including 31 questions was conducted in fighter, fighter trainer, helicopter, and transport aircraft units of the Finnish Defense Forces., Results: Of the pilots who responded, 136 (93%) had used or tried m-CEPs and 90 (62%) were currently using them. There are many benefits to m-CEPs: they seem to enhance experienced speech intelligibility, since 85% of the pilots who had experience about them reported improved speech intelligibility under difficult hearing conditions, and 93% would recommend them to other pilots. It seems m-CEPs provide equal benefits to pilots with and without current hearing problems. They were also considered better than previously used hearing protectors. Still, problems were common: 82% of the pilots reported m-CEP related drawbacks, of which technical problems and discomfort issues were the most prevalent., Discussion: Most military pilots hold a positive opinion on m-CEPs and are willing to recommend their use. Technical problems and discomfort issues are, however, relatively common.

It was explored how three types of intensive cognitive load typical of military aviation (load on situation awareness, information processing, or decision-making) affect speech. The utterances of 13 male military pilots were recorded during simulated combat flights. Articulation rate was calculated from the speech samples, and the first formant (F1) and second formant (F2) were tracked from first-syllable short vowels in pre-defined phoneme environments. Articulation rate was found to correlate negatively (albeit with low coefficients) with loads on situation awareness and decision-making but not with changes in F1 or F2. Changes were seen in the spectrum of the vowels: mean F1 of front vowels usually increased and their mean F2 decreased as a function of cognitive load, and both F1 and F2 of back vowels increased. The strongest associations were seen between the three types of cognitive load and F1 and F2 changes in back vowels. Because fluent and clear radio speech communication is vital to safety in aviation and temporal and spectral changes may affect speech intelligibility, careful use of standard aviation phraseology and training in the production of clear speech during a high level of cognitive load are important measures that diminish the probability of possible misunderstandings., (© 2011 Acoustical Society of America)

Caffeine has been suggested to act as a countermeasure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown under sleep deprivation. However, subjective evaluation of overall flight performance in the caffeine group tended to be too optimistic, indicating a potential flight safety problem. Based on our results, we do not recommend using caffeine pills in military flight operations.