(CNN) More than 170 killed after South Korean jet crash-lands at airport. Here’s what we know. 

The crash is reported to be subsequent to a bird strike. In advance of technical details, there is an explanation with some plausibility. In what follows, supposition is stated as fact:

Ground-to-air photography shows the thrust reversal door open on the right engine. This is not the result of pilot action to a engage thrust reverser. The open door is the result of uncontained engine failure. Consequent to the bird strike, the engine containment structure failed, due to the high centrifugal acceleration of rapidly rotating engine components.

The right engine ejected shards of metal which impacted the right wing, severing hydraulic lines of multiple  redundant systems. These lines incorporate hydraulic fuses. When a hydraulic line ruptures, a fuse acts to isolate the ruptured section. Failure of a hydraulic fuse to perform this function may have contributed to severity.

The ejected metal also severed the manual cable backup for lowering the right landing gear. To avoid asymmetric friction on the runway, this left the pilot with no choice but to leave the left wing and nose landing gear retracted.

The above also explain the failure to  extend the flaps, which resulted in high approach speed, with touchdown further down the runway than would result from a normal glide path. Despite these difficulties, the pilots managed to control the plane to what could have been a successful belly landing.

As remarked by 737 pilot Denys in  (YouTube) Pilot Blog | Airline Pilot about Crash of Jeju B737 at Muan | No gear | Bird Skrike | Concrete wall, the ultimate cause of the tragedy was the decision of airport administration to place a completely unnecessary concrete wall at the end of the runway.