Complex sentence: While the Iraqi air force was busy fighting the Iranians and did not notice most of the time, on one occasion, an Iraqi Mig-21 chased an Israeli F-4; the Iraqi jet ran out of fuel and the pilot was forced to eject.
Split into simpler sentences: While the Iraqi air force was busy fighting the Iranians and did not notice most of the time. The Iraqi jet ran out of fuel and the pilot was forced to eject.