Crew resource management: a simulator study comparing fixed versus formed aircrews.

BACKGROUND: Most airline and military transport planes are flown by crews that have been teamed together for a short amount of time before disbanding and becoming part of a different crew (formed crew concept). Some military operations use a fixed crew concept, pairing crewmembers together for an indefinite period. This research investigated the effect of crew formation policy on aircrew performance during missions in U.S. Air Force KC-135 (tanker) simulators. METHOD: The performance of fixed aircrews is compared to formed aircrews flying the same simulator mission scenario, which included an in-flight emergency. Cockpit resource management (CRM) behavioral data and error data were collected by trained observers for 17 crews (9 fixed and 8 formed). RESULTS: The results show that fixed crews committed more minor errors (4.4 per mission) than formed crews (2.6 per mission), t(14) = 2.32, p = 0.036. No differences were found concerning major errors or CRM behavioral indicators. CONCLUSIONS: The results suggest the possibility of a "familiarity decline," where aircrew performance declines when crewmembers become too familiar with each other and may affect flight safety.

Comparison of fixed versus formed aircrews in military transport.

Historically, transport crews are formed to fly a brief series of sorties together. But what would be the effect of keeping crews together longer? This research investigates the effect of crewing policies on accident rates. We compare the crew coordination performance of fixed teams that work together indefinitely with that of formed teams that work together for shorter periods. We researched 74 accident investigation records of two jet transport aircraft of the U.S. Air Force over 20-year periods. These aircraft used both fixed and formed crews. The "ineffective crew coordination" accident rates for formed crews were significantly safer (z = 12.5 for one aircraft and 2.1 for another p < 0.05). This may imply that airlines and military commands could enhance flight safety by following a formed crew policy. However, further study is needed to identify more completely the effects of crew policies on sortie effectiveness.