BUTTE, Montana Plane Crash

[KSYR-pjr]

According to AvWeb:

The reason for the diversion has not been released but Butte would have been a closer alternative if the pilot had been experiencing problems.

I haven't looked at the charts to confirm if that's true or not.

FlightAware shows the aircraft's track as coming in from the southwest.  In looking at the sectional chart the two airports are about 57 nm apart, with the accident airport on the left of this image:



It doesn't seem that great a difference between the two considering the track from the southwest - perhaps only a few minutes closer.

[48t03c24]

Maybe the pilot decided to avoid a towered airport and the possibility of being reported for overloading a 12 seat plane.  So he opted for the uncontrolled field in Butte thinking they could meet car service there after landing.  Not sure how this will be confirmed unless or untill we review the communications between the pilot and tracon or the tower at the airfield in the original flight plan or some fllight following clips.

[KSYR-pjr]

Maybe the pilot decided to avoid a towered airport and the possibility of being reported for overloading a 12 seat plane. 

That's wouldn't happen, as ATC does not act as an FAA cop for those types of infractions.  I would bet that 99.9 percent of all controllers interviewed would not know the useful load of a PC-12, or most aircraft for that matter.  Add to this the fact that a controller would have to monitor and estimate the weight of each passenger disembarking, know the fuel loaded and then used for the flight, and monitor and estimate the weight of the luggage, all while coordinating the arrivals and departures of other aircraft (many smaller class D airport have one controller working both tower and ground), and you can hopefully see how impossible that would be.

The only pilot infractions that ATC would report would have to do with loss of controlled ground movement or air separation due to a pilot's (in)actions.

[Fourthwind]

If you look at the flight aware track on this plane you will notice that at the end he made a pretty big lockeed turn back to Butte.  Suggests in flight issue's.  As for the seating arrangment, that plane likely had the commuter seat set up.  No bathroom, which is why the kids had to use the bathroom in oroville. You could in that configuration have 12 seats in the back without an issue.  I can't remember if that was an approved amount or not, but it could be done.   I worked on that plane and did the avionics test flight back when I worked for Pilatus.  All the eyewitness reports tells me he stalled it trying to get into Butte.  Unrecoverable in the PC-12 which is why it has a stick pusher.  still leaves a lot of questions as to the type of emergancy he was having.  I doubt it was an overweight issue.  That plane is a flying tank.  God rest their souls.

[Hollis]

Latest FAA report says souls on board were 13 pax and 1 crew. Perfectly legal in the Commuter configuration.

[KSYR-pjr]

If you look at the flight aware track on this plane you will notice that at the end he made a pretty big lockeed turn back to Butte.

With regard to the diversion's alteration from the original plan, I would respectfully disagree.  Here is the track on FlightAware with an annotation where it seems the diversion occurred:



Again, in noting the time and fuel use difference between the two airports, the two appear minimal.  Also worth noting is that in looking at the track there were actually at least three uncontrolled public airports right over the aircraft's path or much closer at the point of the diversion than the accident airport.

Now, I am not stating that it wasn't an emergency diversion since it really is too early to know anything but rather that this diversion isn't an obvious indication of a mechanical issue to me given the above facts.


edit:  At a ground speed of 264 kts (reported by FlightAware), the difference in time between the two airports would have been 7 minutes.    KDLN (Dillon), an IFR uncontrolled airport, was actually seven minutes closer to the aircraft than the accident airport.

[mhawke]

Maybe the pilot decided to avoid a towered airport and the possibility of being reported for overloading a 12 seat plane.  So he opted for the uncontrolled field in Butte thinking they could meet car service there after landing.  Not sure how this will be confirmed unless or untill we review the communications between the pilot and tracon or the tower at the airfield in the original flight plan or some fllight following clips.

Butte is a towered and controlled field from dawn to dusk.

[KSYR-pjr]

Butte is a towered and controlled field from dawn to dusk.

According to AirNav.com, the field doesn't have a control tower:  http://www.airnav.com/airport/KBTM

[mhawke]

According to AirNav.com, the field doesn't have a control tower:  http://www.airnav.com/airport/KBTM

I stand corrected..... Some days I can't read as well as others..

[Fourthwind]

If you look at the flight aware track on this plane you will notice that at the end he made a pretty big lockeed turn back to Butte.

With regard to the diversion's alteration from the original plan, I would respectfully disagree.  Here is the track on FlightAware with an annotation where it seems the diversion occurred:



Again, in noting the time and fuel use difference between the two airports, the two appear minimal.  Also worth noting is that in looking at the track there were actually at least three uncontrolled public airports right over the aircraft's path or much closer at the point of the diversion than the accident airport.

Now, I am not stating that it wasn't an emergency diversion since it really is too early to know anything but rather that this diversion isn't an obvious indication of a mechanical issue to me given the above facts.


edit:  At a ground speed of 264 kts (reported by FlightAware), the difference in time between the two airports would have been 7 minutes.    KDLN (Dillon), an IFR uncontrolled airport, was actually seven minutes closer to the aircraft than the accident airport.

The lockeed turn I was refering to was at the Butte end of the flight.  Not a track change.  It was a wide sweeping turn which looks like someone doing energy managment.  He may have also made a judgment based on the capabilites of the airport.  We will likely never know.  The last Pilatus that made a nose down crash like this is still an unknown cause.  There were some pilots that were pulling the breaker on the stick shaker computer because they didn't like the shaker going off at touchdown.  If he did this then there would have been no stall warning. 

[KSYR-pjr]

The lockeed turn I was refering to was at the Butte end of the flight.  Not a track change. 

Okay, but in your first post you stated, "If you look at the flight aware track on this plane you will notice that at the end he made a pretty big lockeed turn back to Butte."

Interesting information about the pilots pulling the breaker, however.

[KSYR-pjr]

The lockeed turn I was refering to was at the Butte end of the flight.  Not a track change.  It was a wide sweeping turn which looks like someone doing energy managment. 

Are you, by chance, referring to this here?



This was the track out of the departing airport.

[KSYR-pjr]

USA Today, has an updated article that includes some more information about the accident.

Article is here:  Pilot gave no warning of trouble before Mont. crash 

Oh, and to offer another theory about the diversion:  Given that Bozeman had an ILS to 200ft minimums whereas Butte had an ILS to 1100 ft minimums, it is very prudent (and even regulatory) for pilots to file to a less-than-desired landing airport with a lower approach given early weather forecasts, and then divert to the "desired" airport with higher minimums once landing weather conditions are known en route.

[Fourthwind]

You are correct.  My mistake..  I didn't look at the identifiers when I browsed through flightaware.  I had it backwards.  My initial check in of the sight was to see if I had worked on that bird.  should have studied it further. 

I agree with the flight plan diversion theory.  We used to do the same thing going into Trukee. 

Still wondering about the stick shaker stall system.  The plane basically flies like a P-210 except the roll is heavier.  Heavily loaded the stall speed would have been about 5 to 10 knots faster than standard approach of 80 knots over the fence, and faster still if he had been in icing conditions. SOP for that series says you should only use 15% flaps after flying in ice.  Makes you wonder..  we will likely never know with the amount of damage to the plane.

[mhawke]

Latest info on MSNBC has family names and ages.  They were headed to the West Yellowstone club.  A bankrupt (but still operating) private ski resort and housing complex for the really rich.  Bill Gates just purchased a home there last year.

Anyways, my point is that the 'ideal' airport to go to, would be Bozeman to get to West Yellowstone club.  Doesn't mean they weren't planning on going to Butte for some reason, but then they would be making a longer drive.  Many of the people who live at West Yellowstone club actually have a rented garage at Bozeman airport for their car.  (There are multiple 2 car, heated garages, in the parking area of the airport).

[SJ30]

The very first thing I should do is extend my prayers for the families of those who survive [were left behind at home] this tragedy, for they are the one's who need the prayer the most.

Not a pilot yet, but doing lots of pre-study before I begin my training.  I do have designs on owning and flying a high-performance light business jet, which happens to be the highest performing and most capable in its class [if it even has a class].  I also plan to make aerobatic flying a integral part of my future personal flying career as well.  So, I want to make sure that I am as safe and proficient a pilot as I can be.

To that degree, I've been doing some study and came upon the topic of High Density Altitude.

I have not yet heard anyone string together the logic of where this pilot lived and operated his PC [Southern California] and compared that to where his ultimate destination was in Montana.  Granted, his destination airport was not KFTG at over 5,500 ft pressure altitude, but it was well over 4,000 ft pressure altitude.  I also realize that this is March and not middle July.  But, the probability is growing [the more we learn] that this aircraft might have been at the very least, carrying more passengers [under the rules] than it should have been - children included.  Children ranged from the middle teens down through two (2) years old.

Question:  Since I'm still learning the ropes, could this be an accident that couples an aircraft being operated too close to its OEM load limits in HDA conditions? 

This aircraft made more than one stop at low pressure altitude airports before initiating its final leg to its destination and entering the airspace of an airport sitting at nearly 4,500 ft pressure in Montana.  We don't know whether or not he picked up passengers and thus more weight [including baggage] along the way en route to Montana.

I've heard that density altitude is something to really pay close attention to at all time but especially under two limit conditions:  1) When the aircraft is being operated at or near its MTOW, and 2) When the aircraft is being operated at an HDA airport.

So, I would guess that the third logical extension of that would be when you combine BOTH of those limit conditions at the same time.  Again, there were no high temperatures involved, but it is my understanding that heat is one of the biggest HDA factors, not the only one.

I'm trying to learn here and make no judgments about the pilot.  I plan to fly with my family as well some day and I would like to be as safe a pilot as I can, so I can related to this accident in a big way regardless of the fact that I don't fly at this particular time with my family.   

[joeyb747]

How mountainous is the terrain around Butte? I'm recalling something about horizontal vorticies coming off mountains causing flight upsets. I believe that was in the Colorado Springs area. Any possibility that could have been a factor? I am not familiar with the Butte area.

[joeyb747]

Here is some information I found on the phenomenon called "rotors", or horizontal air disturbances associated with mountains. Montana is in the "Danger Zone" as having a higher chance of the event occurring.

Not putting too much into this, but it was just an idea...and some pretty interesting stuff.

Rotors gained attention after the crash of a United B737 at Colorado Springs a few years back, but they have been studied for years, all the way back to the 1950's. In this report, it notes a B747 suffering engine separation from this phenomenon while taking off from Anchorage.

http://www.etl.noaa.gov/about/eo/science/AC00571.pdf

[KSYR-pjr]

Question:  Since I'm still learning the ropes, could this be an accident that couples an aircraft being operated too close to its OEM load limits in HDA conditions? 

The airport has an elevation of 5,550 feet above sea level.  Considering the temperature (6c), dew point (-1c), and baro pressure (29.56) taken around the approximate time of the accident the density altitude calculates to 6,302 feet.    Wiki  reports (Pilatus site still unreachable for me) a service ceiling for the PC-12 of 30,000 feet.   

While operating over gross certainly affects the performance of an aircraft, it seems to me that this particular calculated density altitude would not have been a sizable performance detriment to this particular aircraft model. 

However, anything still goes at this point.

[KSYR-pjr]

I was looking at the Google Maps image of the Butte airport and noticed that the cemetery in which this accident occurred is actually to the side of the runways.  From the various news reports I was expecting the cemetery to be under the approach path of one of the runways.  This seems to indicate that the aircraft was maneuvering, or circling to land and not, as I assumed, approaching straight in:

[Hollis]

Prime suspect is now icing. Sound familiar?

[joeyb747]

Prime suspect is now icing. Sound familiar?

I was looking at the images from flightaware, and noticed weather all along the route. Icing flashed into my mind, but I wasn't sure about it. Who is reporting icing? Just curious.

[mhawke]

How mountainous is the terrain around Butte? I'm recalling something about horizontal vorticies coming off mountains causing flight upsets. I believe that was in the Colorado Springs area. Any possibility that could have been a factor? I am not familiar with the Butte area.

Just a few miles east of the airport is the continental divide, peaks there in the 8-10K ft range.  Same thing to south of airport.  To west is a large rise.

It is essentially in a valley and surronded by mountains on three sides, and large hill to the west.  I think that is way it is essentially a visual approach.  It has ILS, but from what I know, is flown uncoupled, and the minimums make it essentially a visual approach and landing because the mountains are so close there is no room for error.

It can be interesting to watch the planes fly in, coming over the hills to the north of the airport to land.

I have personaly only flown into Butte once.  I travel there fur business, but fly to Bozeman and drive over.  It seemed for a stretch that everytime I had tickets to Butte, I ended up landing in Helena or Bozeman anyway because the airport was closed.

[KSYR-pjr]

I have personaly only flown into Butte once.  I travel there fur business, but fly to Bozeman and drive over.  It seemed for a stretch that everytime I had tickets to Butte, I ended up landing in Helena or Bozeman anyway because the airport was closed.

AvWeb just put out an article that supported your question about the diversion being farther from the resort:  PC-12 Crash Probed, 14 Dead

The article seems to discount icing as a factor, since the PC-12 is certified for known ice and that the temperature a few thousand feet above ground was above freezing.    It also ponders the idea that this could be nothing more than a classic got-too-slow-while-maneuvering-and-stall/spun-it-in, which seems far fetched given the ex-Air Force, 2,000 hour-in-type pilot flying the aircraft.

[SJ30]

The airport has an elevation of 5,550 feet above sea level.  Considering the temperature (6c), dew point (-1c), and baro pressure (29.56) taken around the approximate time of the accident the density altitude calculates to 6,302 feet.    Wiki  reports (Pilatus site still unreachable for me) a service ceiling for the PC-12 of 30,000 feet.   

While operating over gross certainly affects the performance of an aircraft, it seems to me that this particular calculated density altitude would not have been a sizable performance detriment to this particular aircraft model. 

However, anything still goes at this point.

Thanks, this is what I was looking for.

Ok, I missed the part about the cancellation from the filed destination over to Butte, which according to Airnav.com, sits at 5,550 msl. 

I called ATIS [Bozeman] yesterday and got information enough to derive the density altitude and it was even lower than what you just listed for Bert Mooney Airport.  So, with a service ceiling of FL300, I guess this should have been no problem for this particular PC.

I hope this is NOT going to be another icing situation......again.  Every PC-12 that I've seen has de-icing boots on the leading edges of both wings and the horizontal.  Though, I've seen none with the boot on the leading edge of the vertical.