Early Analysis: PC-12 In-flight Breakup Over Stagecoach, Nevada

let's take an early look at the Pilatus pc-12 accident this one happened where a pc-12 with five people aboard a single pilot two medical professionals a passenger a patient and a patient's family member were departing Reno Nevada in route to Salt Lake City about 14 minutes into the flight the pilot loses control of the aircraft and it spirals down and crashes all five people aboard Parish so what happened we'll look at the conditions the pilot and the equipment so we start with the conditions they will almost certainly be a factor in this accident a winter storm was passing through the Reno area visibility was about a mile and three quarters in light snow and the temperature was negative one Celsius on the surface so the pilot was departing in demanding conditions single pilot Knight IFR into turbulence and moderate icing the pilot departs as we can see from the profile here in the first few minutes of the flight seemed to go normally but then in the last minute or so as the pilot levels off he's in route to flight level 250. and at about 19 400 feet or so according to adsb data the pilot loses control of the airplane we can see it peel off to the right and then enter a spiral and until the crash the conditions were certainly demanding and that kind of visibility in snow and ice now the Pilatus aircraft is made for this kind of flying it has fiki so flying into known icing capability the fact that there was a Signet for turbulence and moderate icing in root would certainly have gotten the Pilot's attention he would have wanted to plan for that so let's look at the likely causes or the things the NTSB will look at to investigate during this accident the Pilatus now this isn't a pc-12 but you can see the t-tail on this aircraft is like a Pilatus it's it's a hightail with a high horizontal stabilizer if you look at stalls of a Pilates when a Pilates stalls it breaks off pretty aggressively in One Direction or another in the videos I saw it would break off in more than 90 degrees of Bank when it stalled so if a Pilates stalls it is a pretty aggressive stall response we know the ntsbc said that the aircraft broke up before it impacted the ground in the NTSB said the horizontal stabilizer and the outboard right wing of the airplane broke off and they were found about a mile or so away from the impact site that's how they know it came apart before it hit the ground the NTSB mentioned they have difficulties there's no recording devices on the airplane but they may be able to download some data from the avionics inside the aircraft and that's what we're hoping they can find we mentioned the conditions will certainly be a factor in this accident so from the time the aircraft Departed the pilot was in icing conditions the segment had tops of the potential icing up to two zero zero the pilot enroute to flight level 250 but he never gets above 1904 before he loses the aircraft so if the icing systems weren't working if the icing was so heavy that it overcame the icing systems in the Pilatus or if the pilot was delayed in activating any of the icing systems that could have caused a loss of control the ice could have built up on the aircraft on the wing structures and the tail so fast and so rapidly or if the ice built up inside the engine and the inertial separator wasn't engaged in time or appropriately then reduced thrust could have happened and it could have choked the engine so those factors could have been a cause of why the aircraft didn't climb above 1904 and why the pilot lost control the second issue that could have happened is after the pilot loses control the airplane then pulled incorrectly I should say or too aggressively then he could have snapped off the horizontal stabilizer in the right outboard Wing in that case that would have made the aircraft unrecoverable and in fact looking at adsb data we can see that it's an aggressive descent profile once the aircraft departs it goes into a very NOS low spiral which indicates at some point the aircraft had come apart and was now completely unair Worthy the other factor in the environment that day was turbulence turbulence over that part of the country can get pretty aggressive pretty quickly it's a potential that the turbulence caused the breakup of the aircraft and turbulence caused the horizontal stabilizer to depart in that right outboard wing and that's what initiated the loss of control sequence so icing or turbulence are the factors that may have caused the loss of control to begin with a third factor is the potential for spatial disorientation the pilot is flying single pilot it's at night it's in IMC conditions and light blowing snow that can be disorienting to a pilot and if for some reason the pilot got disoriented and lost control due to spatial disorientation and then in the recovery maneuvered inappropriately or too aggressively and snap those control surfaces off that's another potential cause of the of the loss of control in the crash in the NTSB will try to determine that as well so what are the lessons learned that we can take away as pilots from what we know so far is to think heavily about the conditions that you're going to fly into night IMC blowing snow icing conditions turbulence and all of that single pilot IFR that is as demanding As It Gets in GA as demanding As It Gets in any kind of flying so the go no good go no-go decision and whether or not we would fly in those conditions is something to think hard about and a consideration for us to think about under this accident is to make sure we understand our icing equipment is it anti-ice or de-ice in this case this was a fiki equipped airplane flight into known icing to make sure that we get ahead of that anti-icing and de-icing because almost all of those systems anticipate you being ahead of the icing conditions or knowing that they're coming so if the pilot got into icing it was difficult to see maybe it was accumulating faster than he realized if he didn't get on his icing equipment and get onto that early and have it be preventive enough or to de-ice the airplane in time then that certainly could have caused degraded performance icing degrades everything about performance in an airplane it can degrade the thrust inside your engine or on your propeller it certainly degrades the lift it adds more drag it adds more weight so icing conditions are problematic this accident reinforces how important it is that if you know you're going to fly into icing conditions to make sure you're ahead of your icing equipment and get in front of it since this accident brings up ice in considerations another thing for us to review is the minimum air speed during a climate icing conditions that can be an Insidious problem for pilots and what happens is a lot of airplanes have a minimum climb speed so that your angle of attack doesn't get such that ice builds up underneath the control surfaces now I don't know if a pc12 has a minimum climb speed in icing conditions to it but it reinforces the point that as Pilots we need to check to see if our poh has such a limitation and if it does the importance of adhering to it and then the potential for spatial disorientation so let's try to put ourselves in the cockpit of this pilot he's in an airplane that's not performing as he's expecting there's some it's a high workload involved in the flying he's working his icing equipment he's on a departure and now suddenly if he goes heads down and the aircraft rolls off in some kind of unusual attitude how Insidious that can be to catch up to you so it reinforces the need for a cross check it reinforces the understanding of how that can happen and the importance of seeing it identifying it verifying it and then inputting the correct recovery response so again spatial D single pilot operations in blowing snow in these kinds of conditions would have been a potential Factor so we'll keep tracking this as NTSB releases a preliminary report and more information stay tuned thanks for supporting aopa and thanks for watching

Channel: Air Safety Institute

Views: 183,222

Keywords: institute, aopa, aviation, pilot, fly, flying, flight, plane, airplane, airport, air, safety, asi, air safety, training, aircraft, owners, pilots, Loc and Low-Altitude Flying, Icing and Cold Weather Ops, Advanced Training, Thunderstorms and Turbulence

Id: kVR_uA6bONY

Length: 9min 26sec (566 seconds)

Published: Tue Feb 28 2023