The National Accountability Bureau summoned Pakistan Tehreek-e-Insaf Chairman Imran Khan and the country's probable prime minister-in-waiting on August 7 in a case pertaining to misuse of provincial government helicopters.The spokesperson for the Khyber-Pakhtunkhwa division of the accountability body confirmed to The Express Tribune that Imran has been asked to appear before the panel on the given date.NAB is investigating the cricketer-turned-politician for causing Rs2.17 million loss to the provincial exchequer by using K-P government's helicopter for over 72 hours.Imran was summoned on July 18, however, he failed to appear before the panel sighting electioneering. His lawyer had filed an appeal requesting the accountability watchdog to fix the case after the general elections, "preferably on August 7."It is pertinent to note that NAB has already recorded statements of former K-P chief minister Pervez Khattak and four senior bureaucrats in the case.