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Heat stress on helicopter pilots during ground standby.
Aviat Space Environ Med. 1991 Oct; 62(10):978-81.AS

Abstract

We attempted to use measurements of ambient thermal conditions to characterize and then predict thermal conditions in the cockpit before takeoff and during an hour standby period in Bell 206 and Bell 212 helicopters with a crew of two and with the cockpit doors opened. Dry bulb, wet bulb, and globe temperatures were measured on 28 separate summer days. The wet bulb globe temperature index (WBGT) was used to estimate heat stress. Ambient WBGT at time 0 ranged from 13 degrees C to 31 degrees C. There was a 2.9 +/- 3.7 degree difference in WBGT between ambient and cockpit conditions at time 0 which increased to 7.2 +/- 3.5 degrees after 1 h. Because of the cooling effect of opening the helicopter cockpit doors, the cockpit WBGT actually decreased over the standby period when cockpit WBGT values were 30 degrees C or more at time 0. Thus, there was an inverse correlation between cockpit WBGT at time 0 and the change in cockpit WBGT over the 1-h period (r = -0.767, p less than 0.001). The mean WBGT in the cockpit over the 1-h standby period was positively correlated with the ambient WBGT at time 0 (r = 0.783, p less than 0.001). We conclude that the greenhouse effect results in a cockpit WBGT which is significantly higher than ambient conditions. Subsequent changes in cockpit WBGT depend on the balance between heat transfer from the pilot's bodies to the cockpit and the loss of heat after the doors of the helicopters are opened. Ambient thermal conditions can be used to predict heat stress during the ground standby period.

Authors+Show Affiliations

Israel Air Force Aeromedical Center, Tel Hashomer.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

1764011

Citation

Froom, P, et al. "Heat Stress On Helicopter Pilots During Ground Standby." Aviation, Space, and Environmental Medicine, vol. 62, no. 10, 1991, pp. 978-81.
Froom P, Shochat I, Strichman L, et al. Heat stress on helicopter pilots during ground standby. Aviat Space Environ Med. 1991;62(10):978-81.
Froom, P., Shochat, I., Strichman, L., Cohen, A., & Epstein, Y. (1991). Heat stress on helicopter pilots during ground standby. Aviation, Space, and Environmental Medicine, 62(10), 978-81.
Froom P, et al. Heat Stress On Helicopter Pilots During Ground Standby. Aviat Space Environ Med. 1991;62(10):978-81. PubMed PMID: 1764011.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Heat stress on helicopter pilots during ground standby. AU - Froom,P, AU - Shochat,I, AU - Strichman,L, AU - Cohen,A, AU - Epstein,Y, PY - 1991/10/1/pubmed PY - 1991/10/1/medline PY - 1991/10/1/entrez SP - 978 EP - 81 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 62 IS - 10 N2 - We attempted to use measurements of ambient thermal conditions to characterize and then predict thermal conditions in the cockpit before takeoff and during an hour standby period in Bell 206 and Bell 212 helicopters with a crew of two and with the cockpit doors opened. Dry bulb, wet bulb, and globe temperatures were measured on 28 separate summer days. The wet bulb globe temperature index (WBGT) was used to estimate heat stress. Ambient WBGT at time 0 ranged from 13 degrees C to 31 degrees C. There was a 2.9 +/- 3.7 degree difference in WBGT between ambient and cockpit conditions at time 0 which increased to 7.2 +/- 3.5 degrees after 1 h. Because of the cooling effect of opening the helicopter cockpit doors, the cockpit WBGT actually decreased over the standby period when cockpit WBGT values were 30 degrees C or more at time 0. Thus, there was an inverse correlation between cockpit WBGT at time 0 and the change in cockpit WBGT over the 1-h period (r = -0.767, p less than 0.001). The mean WBGT in the cockpit over the 1-h standby period was positively correlated with the ambient WBGT at time 0 (r = 0.783, p less than 0.001). We conclude that the greenhouse effect results in a cockpit WBGT which is significantly higher than ambient conditions. Subsequent changes in cockpit WBGT depend on the balance between heat transfer from the pilot's bodies to the cockpit and the loss of heat after the doors of the helicopters are opened. Ambient thermal conditions can be used to predict heat stress during the ground standby period. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/1764011/Heat_stress_on_helicopter_pilots_during_ground_standby_ DB - PRIME DP - Unbound Medicine ER -