5 Takeaways From The Times's Investigation Into the Jan. 29 Collision at National Airport

[Cirsium]

5. Five take aways

• The Black Hawk crew was under "see and avoid" rules. See and avoid lightens the controllers workload, but can go very wrong, as it did in this case. They didn't see and they didn't avoid.

• The FAA regulations say that the air traffic controller should “advise the pilots if the targets appear likely to merge.” The controller did not give an urgent or clear warning.

• "Some of the controller’s instructions were 'stepped on' — meaning that they cut out when the helicopter crew pressed a microphone to speak — and important information likely went unheard." Also, the Automatic Dependent Surveillance-Broadcast, or ADS-B, broadcasts an aircraft’s position, altitude and speed on the Black Hawk was turned off.

• "The route the helicopter was flying and the runway the jet was using to land formed a particularly dangerous combination." The controller was executing a "squeeze play" - "tightly sequencing runway traffic with minimal time between takeoffs or landings. " That meant there was little margin for error.

• The co-pilot on the Black Hawk told the pilot that the controller wanted them to turn, which would have prevented the collision. The pilot either did not hear that or ignored it.