Excellent summary here by Captain Steve, on the latest preliminary report by the NTSB. As has been earlier surmised, a dual engine flameout caused by complete fuel starvation forced the crew to make an immediate decision to locate any piece of concrete, to the right, and short of the runway. There does appear to be a complicated cascading of mechanical failures that contribute to the broken fuel line, exhausting all the fuel from both the right and left tanks. Whether the cross feed valve was opened by the crew and then subsequently locked in place by an electrical failure may be a key finding. I’m not familiar with that system to know if the crew can manually override a cross feed valve that is stuck in place because of electrical failure.

A complete metallurgical analysis of what went wrong will be the next step in the investigation. Obviously there was some kind of metal fatigue, or a propagation of a crack somewhere that resulted in multiple systems failures. Mechanical failure could have emanated from generators, fuel pressure switches, various clamps holding things together, punctured fuel lines, screws missing or popping out. There is simply too much complexity right now to offer a sufficient explanation as to what happened. That will come with a complete breakdown and analysis of all the failed parts, and the order in which they occurred. The crew knew they had a serious emergency developing because of the confusing array of CAS (crew alert system) messages. It’s extremely difficult to analyze inflight what was happening at that moment, given all the confusing alerts, so they correctly elected to divert immediately into Laredo and get the aircraft on the ground asap, once events began to cascade out of control. There will be an intense analysis on whether or not any scheduled inspections were missed or were coming due on various systems. Metal fatigue and propagating cracks, can be discovered early if correct quality control standards are in place to monitor and inspect these things. More to come in the final report.

The only point where I may disagree a bit with Captain Steve is his view on a communication hiccup between ATC and the flight crew concerning the lead-in distance to their final approach. The crew may indeed have insisted on a 5 mile final, but given their precarious fuel status, they stayed as high as possible, for as long as possible, to retain energy for the descent. Staying high preserves fuel, and a wide 270 degree base to final would also allow them to keep their throttles at idle for as long as possible during that extended, wide, and circular controlled descent, again maximizing fuel conservation. They were already very high, and positioned over the top of the field. So, it is possible that ATC knew, through experience, that the crew would need MUCH MORE TIME AND DISTANCE to get down, and setup checklists on final with enough time to extend gear/flaps and slow to approach speed. So, ATC extended their final out to 14 miles, instead of the 5 requested by the crew. It was a judgement call. Perhaps, it may have worked better to extend the final to something in between 5 and 14 miles. If the crew executed that wide descending turn to the point where they were only 5 miles out on final, it could have been entirely possible to be much too high and fast to land, in which case, a go-around would not be achievable if they were sucking fumes, and nearly out of gas. This was obviously a delicate maneuver that required perfect airmanship and coordination between both ATC and the crew to effect the optimum flight path to get the aircraft on the ground. In this case, an emergency aircraft and its crew CAN override ATC’s direction, and if the crew requested a 5 mile final, then it was incumbent on ATC to try and make that happen as best as possible. This maneuver will probably be played out in the simulator to see what would have been the optimum distance on final approach in order to make a safe landing onto the runway before flameout, without forcing them to land short on the freeway. Certainly this was a Herculean task for both the crew and ATC to collectively optimize the final descent and landing when they simply didn’t know how much fuel was left. Besides that, the gages were indicating spurious information, and their focus was on flying the damn aircraft and not measuring every once of fuel at that point. This isn’t something practiced every day, so I think the crew did an outstanding job getting this plane on Terra Firma, given all the pressure and unique challenges they were facing that night. The final report will thoroughly analyze these last minute decisions. But, right now, they are probably more laser focused on examining the metallurgy and mechanical failures so that fleet-wide inspections can be conducted asap to prevent this from happening again. YouTube: NetJets Citation Crash: New NTSB Findings Raise Serious Questions (Captain Steeeve)