gravel from an improperly packed gravel runway to be sucked into the engines causing "foreign object damage", thus the need for the kit. In 1974 the Peruvian Air Force purchased two 25Bs with a belly pod that contained an aerial survey camera. Many Learjet 25 aircraft remain in regular use today, particularly in the United States, Mexico, and Canada. Noise compliance In 2013, the FAA modified 14 CFR part 91 rules to prohibit the operation of jets weighing 75,000 pounds or less that are not stage 3 noise compliant after December 31, 2015. The Learjet 25 is listed explicitly. Any Learjet 25s that have not been modified by installing noise compliant engines or "hushkits" will not be permitted to fly in the contiguous 48 states after December 31, 2015. Exceptions may be granted. Variants The ICAO designator as used in flight plans for all Learjet 25 models is LJ25. Learjet 25 FAA certified on October 10, 1967. Learjet 25B Improved version. FAA certified on September 4, 1970. Learjet 25C Improved version with greater fuel capacity. FAA certified on September 4, 1970. Learjet 25D Longer-range version. Learjet 25G Introduced September 23, 1980. During a series of demonstration flights lasting from June 9 to 18, 1982, the 25G broke a number of long-distance speed and fuel consumption records. Operators Civilian operators Olympic Airlines TAESA Military operators Bolivian Air Force Mexican Navy Former military operators Peruvian Air Force NASA Accidents and incidents On 18 January 1977, Džemal Bijedić, prime minister of Yugoslavia, his wife Razija and six others were killed when their Learjet 25 crashed on the Inač mountain near Kreševo, Bosnia and Herzegovina. The plane took off from Batajnica Air Base in Belgrade and was en route to Sarajevo when it crashed, ostensibly due to poor weather conditions. On May 18, 1983, a Learjet 25B flying from Wien-Schwechat International Airport, Vienna, Austria to Hamburg-Fuhlsbüttel Airport, Hamburg, Germany, did not respond to controllers' requests 40 minutes after takeoff. The aircraft, registered D-CDPD and operated by Air Traffic Executive Jet, was carrying two crew and one passenger. It continued in flight at until its fuel was exhausted. It crashed into the Atlantic 350 miles (560 km) northwest of Scotland. On 2 March 1996, the Brazilian comedy rock band Mamonas Assassinas were killed while approaching Guarulhos International Airport, the major airport serving the city of São Paulo. The plane made a previous landing attempt and