What happened
A charter flight operated by Saudi Arabian Airlines, traveling from Jeddah to Ankara, was forced to divert to Istanbul-Yeşilköy Airport after receiving reports of low visibility caused by fog. While performing the approach to runway 24, the crew noted that the Visual Approach Slope Indicator (VASI) displayed a red light and that the aircraft's altitude was too low. In an attempt to correct the descent, the captain increased engine power; however, the Boeing 747 continued to descend, striking the ground approximately eight meters before the runway threshold.
The impact caused significant structural damage, including the separation of the number one left engine and the loss of both the central and left main landing gear after hitting a concrete block at the runway shoulder. Following the impact, the aircraft slid several hundred meters on its fuselage, veered left, and eventually caught fire in a nearby grassy area. Despite the intensity of the fire, all 377 occupants were successfully evacuated from the wreckage, with 10 injuries reported.
Findings
Investigations revealed that the aircraft sighted the runway before reaching the NDB but crossed that waypoint roughly 600 feet below the required minimum altitude. During the final approach, the flight path remained consistently below the standard 3-degree glide slope indicated by the VASI. A significant contributing factor was identified regarding the crew's reliance on radio-altimeter call-outs for altitude monitoring, which led to a low approach due to local terrain characteristics.