The NTSB has called the FAA’s response “unacceptable” to four out of six safety recommendations addressing human fatigue and duty-time limitations. The recommendations include requiring training, check flights, ferry and repositioning flights to be included in a pilot’s total revenue time; ensuring that flight- and duty-time limitations take into consideration research findings in fatigue and sleep issues; reviewing the issue of personnel fatigue in aviation maintenance; and taking into consideration the length of a duty day, starting time and workload when assigning flight crew hours. The FAA to date has not altered a 2001 Federal Register notice that calls for eight hours of rest in any 24-hour period that includes flight time. An FAA spokesman told AIN, “We believe the rules and guidance we have in place are fundamentally sound.”