How many weeks' holiday a year are there? <a href="http://butwalpost.com/%E0%A4%B8%E0%A4%AE%E0%A4%BE%E0%A4%9A%E0%A4%BE%E0%A4%B0/2018/05/3944.html">quality meds delivery</a>  "No aircraft in the history of aviation has crashed because a pilot has gone to sleep at the controls," says David Learmount, a former RAF Hercules pilot and safety editor at trade magazine Flight Global. "It's never happened. On the other hand, crashes that have resulted from fatigue? There are many, many, many of those."