Several pro-LNA MiG-21 fighter jets were also lost between 2014 and 2017 – the first pro-LNA MiG-21bis crashed in the city of Tobruk on 2 September 2014 due to pilot error during a pull-up maneuver while performing in a memorial flypast for another pilot, Ibrahim Al-Manifi, who was also killed in a plane crash few days earlier (Islamists claim that they shot it down), killing its pilot Rafa al-Alani and at least one civilian on the ground. Another pro-LNA fighter jet, now MiG-21UM, crashed due to technical problems during takeoff for a training flight on 18 May 2016 at the Tobruk airport, pilot colonel Mohamed Rabie al-Shawa died in the crash while co-pilot captain Abdul Quader Mohamed survived the crash but was injured. On 29 March 2017, another pro-LNA MiG-21bis crashed at the city of Tobruk after returning from a bombing mission against Islamist positions in the town on Derna—its pilot, LNA air brigadier Saleh Joudah, the commander of the Gamal Abdel Nasser Airbase in Tobruk, was killed in the crash, along with four civilians on the ground. A third pro-LNA MiG-21bis was shot down over Al-Sabri district in Benghazi by Islamists on 17 April during a bombing raid against Islamist positions. Another pro-LNA MiG-21 fighter jet was shot down by Islamists MANPADS over the town of Derna on 31 July 2017 during its bombing raid on Islamist positions in the town of Derna, both of its pilots ejected safely and were then captured by the Islamists. Also, on 18 May, pro-GNA militias launched a successful surprise offensive on the pro-LNA Brak al-Shati air force base in the area of Fezzan in southern Libya, killing over 140 pro-LNA soldiers and civilians (of which 40 were executed after being captured), heavily damaging the Brak al-Shati air force base, and also destroyed one inoperable pro-LNA L-39ZO Albatros fighter jet on the ground.