yesterday july 16 2020 i took a flight from tacoma narrows airport to packwood washington and on landing i experienced a lot of turbulence we got down on the ground safely and shortly thereafter we took off and that's where we experienced our wind shear issues this video includes a lot of analysis but it starts with simply with the takeoff so you'll just see in real time what we experienced on takeoff i had a camera mounted under the left wing and also had a point of view camera mounted on me the pilot so you get to see it from both perspectives you're going to hear the stall warning horn come on a couple of times during takeoff very close to the treetops the wind gusts in the area were reported at 27 knots and there was a lot of turbulence coming with the winds coming off the mountain and interacting with the trees and other terrain features in the valley so it made for the most dangerous takeoff that i've ever experienced if you're interested in seeing the post-flight analysis that i did which would include weight and balance data density altitude calculations and airplane performance data and then i'll reshow the video and stop it at certain points and talk about what was going on with the airspeed and the vertical speed indicator and where and why we were experiencing stalls so if you want to see that portion stick around if not you can just watch the take off itself and see what was happening with the airplane as we barely made it above the treetops this is the route of flight that i programmed into four flight departing packwood arriving tacoma narrows the total flight distance is 77 nautical miles estimated time 49 minutes and fuel burn 8.6 gallons let's zoom in on packwood and take a look at some of the surrounding terrain as you can see it sits in a valley surrounded by mountains on this side to the west 5442 southeast 5980 to the east 6754 so it's completely surrounded by mountains the winds yesterday were coming from this direction from the south west and then as they come over this mountain right here sky mountain they come down into the valley causing severe turbulence in the trees and other features down here in the valley around the airport [Applause] okay pov cam on check check check feet and speak valves trim setting neutral that flight controls right aileron left aileron elevator flight controls free and correct directional gyro re-checking going 2-9 or 0-2-9 or zero set artificial horizon that altimeter set to field elevation fuel quantity the efficient and balanced primer is in and lock mixture full rich and 1800 rpm [Music] good drop back to both rp check light drop scene oil pressure fuel pressure oil temperature ferro suction gauge in the green and pecking title going rpms back to 1000 ammeter check with load new pump and landing light on transponder squawk altitude radios and avionics on its debt for flight landing light is on strobe rotating beacon on flap set for takeoff cabin door latch tops bottoms window secure selector timer is on and switching thanks right tank set time is noted [Applause] ipad graphite connection and we are connected backward traffic cherokee 7428 romeo taking off runway 1-9 straight out departure backward traffic okay we have a slight crosswind the left variable to hold the flight controls to the left okay feet off the brakes full power engine instruments in the green power available for takeoff airspeed indicator is alive looking for 75. up on 70. off the ground [Music] me [Music] so here's an app i find extremely useful for flight planning purposes especially when there's an airport that does not have a weather station on the airport itself this is an app called windy.com up here in the search bar i'm going to go ahead and type in packwood which is the airport that we departed from in lewis county and we're going to go ahead and click on that and as you can see it shows the wind velocity and direction and it's gathering its information from numerous weather reporting stations in the region now this isn't the conditions as they existed yesterday when i took off this is current conditions this is a day later so the speeds and directions aren't necessarily going to be relevant let's go ahead and zoom in on the airport itself and as you can see it's showing the direction of the wind and it's pretty similar to the direction yesterday it was coming over sky mountain and cougar rocks right here and then coming down into the valley here and just above the treetops it was swirling around on the ground itself it was seven to ten knots from variable from about two zero zero to one seven zero which favored runway one nine that was great the problem started when as soon as the airplane got above the treetops and all that swirl started to happen windy.com yesterday around the time of takeoff reported the wind velocity again on the ground about 7 to 10 knots but it showed 27 knot gusts and that was what we experienced just after takeoff now that would be fine if the wind gusts were generally coming from our direction into our direction of flight but unfortunately that wasn't the case the wind was swirling around and so what would happen is on climb out that wind would come in behind the airplane essentially wind shear caused by the surrounding terrain and now all of a sudden you would go from a fairly steady air speed of 85 and then you would have this 25 knot gus come in behind you and it would shear 25 knots off your air speed and which place the airplane into its stall speed and that's why you were hearing the stall warning horn and the stall warning light was coming on on climb out and that fluctuated several times pretty much above the treetops until we got about five or six hundred feet agl so those were the conditions we experienced i highly recommend windy.com especially again when flying into an airport that doesn't have a on station weather and especially if you're flying in the mountains one of the cool things about the app if you look down here at the bottom it also gives you a prediction of weather and wind speed and direction throughout the day going on into the next two days current conditions are indicated right here and as we can see right now the wind gusts are already around 17 knots as we get more toward the middle of the day you can see it picks up to 26 27 knots and that's what we're experiencing yesterday right about here 27 knot winds and if you're interested to know where it's getting its information from in terms of weather you click right here the nearest weather stations and when you click on that you can see it brings up a number of weather stations including right in the town itself so this is a fantastic planning tool wendy.com and that's what we used yesterday but unfortunately you can't predict what the winds are going to be doing as it interacts with trees and other terrain features in and around the airport that's where we experienced our wind shear yesterday another thing i'd like to take a look at in for flight if you go down here where it says more and click on weight and balance right here now this is bringing up the performance profile of the airplane that i have programmed into it you can program in any number of airplanes and you put in its performance profile enter in the information that's relevant to your flight right here and it'll give you your weight and balance data so yesterday i it's just me on board 190 pounds no co-pilot had 36 gallons of fuel in the passenger seat i had my flight bag i estimate that at 10 pounds and then in the baggage area i had about 20 pounds that's just a maintenance kit and some other stuff that i have in there and it shows your total takeoff weight which is 1787 right here and uh it gives your center of gravity loaded as you see it right here and as you can see we're well within the the center of gravity um envelope and i'm going to go ahead and bring up here the weight and balance calculator that i also use and all the data here matches exactly what for flight does so that's a really fantastic tool in for flight that i uh refer to every time i load the airplane for a flight in addition to the weight and balance data for the airplane in terms of climb performance we also have to consider the density altitude at the time of takeoff now when planning a flight you can always go to four flight bring up the airport click on weather and then as you scroll down here it shows you the density altitude right here in in this case at this moment it's 273 feet but since i had to do a look back at what the conditions were yesterday i brought up this information on the internet so this is a terminal area forecast for yesterday july 16 21 35 zulu which is the time we took off this is the nearest airport kilopapa lima uniform which is thunfield in pierce county washington so at the time of time of takeoff we were showing a barometric pressure of 30.02 in inches of mercury and the temperature dew point spread was 26 16 celsius then i went ahead and entered that data into this calculator so we have a field elevation at the airport in packwood of 1057 feet air temperature 25 celsius altimeter setting 3002 in inches of mercury and dew point in celsius is 16. when we click calculate we see that the density altitude of the airport is actually 2580 feet that's what the airplane sees based on all of the conditions whereas the elevation the airport is one thousand fifty seven so we see we have about a fifteen hundred foot difference which also affects the climb performance of the airplane now that we know the density altitude of the airport we can take a look at a rate of climb chart for the pa28140 this is based on two different weights 1950 and 2150 the loaded weight of the airplane as we saw earlier is rounded up to 1800 pounds so we're going to go with the 1950 pound which is the solid line the density altitude the airport is rounded up to 2600 feet so that puts us about right here at 2600 and we take that all the way across to the solid line and we show about a 700 foot per minute climb performance again given the weight of the airplane and the density altitude at the airport at the time of takeoff which is normally a good rate of climb but factor in the wind shear conditions that we experienced and you saw the results of that and we'll take a little bit of a closer look what you're seeing here is track lock data from yesterday's flight taken from for flight and we're going to go ahead and play this in 3d the things to pay attention to here are our altitude in msl and then our ground speed unfortunately there's no way for for flight to portray airspeed keep in mind that there were some strong headwinds and so the ground speed at times is going to show a low number but this will show how the climb out performance was affected by the wind shear so pay particular attention here to the altitude as we climb out this is being played at normal speed this is our take off roll as you see the ground speed increasing 1057 is the altitude of the airport so you'll see just when we left the ground right there the climb out was decent initially we got just barely above the tree level and then we experienced the stall warning horn which was clearly evidence of a wind shear or wind gusts coming from behind the airplane and the climate performance was greatly degraded as you'll see in the video we'll zero in on the air speed indicator and the vertical speed indicator there were times when the climate was nearly flat to maintain a v y climb then all of a sudden when we got about roughly 500 feet hel the climb out normalized the wind gusts subsided and it was a fairly normal climb out after that in fact i experienced this strong updraft after getting above about 500 agl where the airplane was climbing better than the thousand feet per minute i maintain a stall speed table in the for flight checklist so if we click on more and go to checklist we'll see that for this airplane with zero degrees bank angle and no flaps the stall speed is 64 miles per hour this is based on a fully loaded airplane of 2150 pounds below this airspeed the airplane is unable to maintain lift here we are lined up on runway one nine getting ready to take off under normal circumstances given the weight and balance data for the airplane and the density altitude for the airport we would expect a rate of climb of about 700 feet per minute as you'll see just as we get above the treetops that climb performance greatly degrades and a couple of times we experience the stall warning we're going to freeze the video a couple of times and we'll look at the vertical speed indicator the air speed indicator and talk about what was going on at those various times during takeoff full power mention instruments in the green power available for takeoff airspeed indicator is alive looking for 75. everything's normal up to this point as soon as the we get off the ground though you'll see a strong wind gust push us way off center line so i'm correcting for that now okay right there you hear the stall warning horn it gives just a really quick blip now i want to go back a few frames just to see what was going on there so right now i'm going back i want to see what's happening with that airspeed indicator why did that happen and i'm not really sure because i'm not seeing the air speed degrade to the point where it should have gone into a stall so we're going back we're going back a few frames i see it probably right around 70. so i'm not really seeing anything that would give me an indication of why that came on nonetheless though it did come on so at least for a very brief moment that wing lost lift let's go ahead and resume the video i was definitely a little concerned when i heard that and very focused on what was going on so let's take a look at the vertical speed indicator so normally right here we're at a vy climb speed of 85 we should be expecting about 700 feet per minute but we're barely seeing one maybe 200 feet per minute on climb out and as you can see there's some pretty tall trees just ahead of us see the airspeed indicator is very erratic right there we get a full-blown stall warning all right so let's go back a few frames and see what was happening with the airspeed so here we're going back we were at a normal v y climb of 85 and then it went down to about 62 miles per hour and that happened in less than one second so we had about a 20 mile per hour swing in airspeed in less than one second and so we went from a normal vy climb of 85 to below stall speed in the clean configuration and so you can see how that triggered the stall warning light and horn and i knew that i didn't have a lot of altitude to play with so instead of pitching down to recover that air speed i just leveled the nose let it regain air speed and then resumed a v y climb at 85. so they were back at a normal v y so again the if you look at the the the speed we have here it is fluctuating probably between somewhere between 75 and 90. again that's due to the wind gusts but the vertical speed indicator is going from zero to maybe 400 there's zero so we're flat so it went from flat to about five or six hundred feet per minute and these tree tops are not very far below us here we might have 50 feet above those treetops and that obviously had me concerned see that vsi it goes flat it goes up to about 400 feet per minute and right about here you see we're getting kicked all over the place but right about here when we got to about 500 now look at the vertical speed indicator we're about 400 agl right here maybe 450 agl the vertical speed indicator goes from flat to about three maybe four hundred feet per minute all the way up to above a thousand feet per minute all in a couple of seconds and right there you'll see it goes to fifteen hundred feet per minute now i didn't change the pitch attitude of the airplane at all so clearly what we were experiencing before was a down draft and now we're experiencing a significant updraft so again no change in pitch attitude and we went from a vy climb of 85 up to 100 and 1500 feet per minute in rate of climb so there at vy we're at 1500 feet per minute right now on climb out now it's going back down to a thousand now we're going to see it normalize as we get out of that mechanical turbulence so there's about what we expected 700 feet per minute is a normal climb out at vy speed right here of 85 full power engine instruments in the green power available for takeoff airspeed indicator is alive looking for 75. up on 70 and off the ground [Music] me so [Music] so in conclusion what did i learn and what would i do different next time well i learned a great deal this flight allowed me to analyze some video footage from both the pov camera and a wing mounted camera the pov camera was able to see the instruments i was able to associate what i was seeing there with the stall warning horn and when that occurred and so it was an invaluable experience for me it also caused me to go back and do some research on weight and balance data and density altitude and the effects that those are going to have on client performance and i was able to put all of that stuff together and learn a great deal the simple answer to uh what i would do different is i wouldn't take the flight now that i understand the dynamics of valley flying and the summertime temperatures and winds and the effect of those winds accelerating over the mountains down into the valleys and the turbulence that they cause when they interact with terrain features and trees and that sort of thing i would select the time of day when the air is more stable like early morning or a time of year when you typically experience more stable air and do the flight then instead of a summer midday flight it's one thing to look at the weather and see wind direction and speed it's another to experience the types of turbulence that i experienced on this flight and as you saw from the video there were times when the airplane was not only not climbing it was losing altitude and at times even dipping below its stall speed while trying to clear trees at the other end of the runway so i hope that you were able to learn as much as i learned from this experience i appreciate you joining me and i hope to see you again next flight [Music] do [Music] do [Music] [Music] do [Music] so [Music] oh [Music] [Music] you