Learn from the MISTAKES of others!

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Worst fears realized yesterday!! . . . I'm a pretty experienced flyer . . . retired career helicopter pilot with thousands of hours flying low level . . and now 250+ UAV missions in the past year . . you'd think I would know. Coming back to shore from a run in SPORT mode out over the bay, at what I knew and could see by the display was around 120ft+ Altitude. . . . as it crossed right to left about 20-30min front of me . . . I was blinded momentarily by the sun so . . . I looked down at the display quickly to see what the altitude actually was . . Knowing I was fairly low but expecting to be high enough to clear the 1 tall tree to my left . . .before I could focus on the DJIGO4 screen . . WHACK! . . just clipped the top bare branches of the only tall tree around . . and with at least 2 maybe 3 blades blown off it tumbled and hit the ground hard . . . broke just about everything. . . and continued to spin the bladeless motors. . . finally I issued a CSC and it stopped vibrating as I picked it up . .in pieces

HOW COULD THAT HAPPEN ?. . .The telemetry says it hit at 94.5 ft so I obviously was not above 120ft like I thought. The angle looked like I was passing behind and above the tree . . but depth perception is pretty low especially when looking upSun, into a bright sky.

CONTRIBUTING FACTORS:
1. It was cold and I was wearing special touch sensitive gloves but may NOT have been been able to feel the light pressure if I was exerting by resting my left thumb on the stick . . even a slight back pressure probably caused the bird to drop 10-20 ft in the 30-40 second prior to the event.
2. I was VLOS (Visual Line of Sight) not FPV (First Person View) . . if I had been flying just using the FPV camera view I would have noticed I was heading directly toward the tree not passing by it. . . here in Canada FPV flying is not allowed . . it means "no goggles" . . but technically means you should be VLOS looking at the drone not the display at all times.
3. Lack of a pre-planned IMMEDIATE RESPONSE. Flying helicopters in the military we often practiced what is the first automatic reaction to an emergency. . . like if you have an engine failure your immediate response should be to lower the collective and preserve rotor rpm . . you should not have to think about it . . it should be just an instinctive reaction. . . . .
4. Depth perception when looking into the sun or bright sky. Lack of shadows and a bright featureless sky background gives little visual aid in estimating distance or height.
5. Poor path panning. High rate of angular movement (due to close-in pass) leads to lack of situational awareness if you're visual field passes through 180 degrees in less than a second. It takes more than a second or two to become familiar of a rapidly changed scene . . unless your brain gets there before the aircraft as it should.

Being unexpectedly blinded by the sun but fully aware I was approaching obstacles at speed what is the best reaction? . . slow down yes . . but that takes time when not anticipated. You could instinctively turn away from the shoreline but at a critical moment you might just as likely hit something else. The only likely safe place is above you and so the immediate response SHOULD have been to slow down but immediately apply FULL UP command and head for the sky. . . . I waited barely a second too long by thinking "hey that looks a bit low . . woah! sun in the eyes . . . let's look at the display and see what it says" . . WRONG! . . .immediate reaction to my perception of a threat should have been back on the right stick and FULL POWER.on the left . . just for a full second or 2, so I would head for clean air above and give myself time to think and confirm there may be a potential threat here.

Yes this would likely not have happened anyway, had my decision to fly back towards home in SPORT mode been better thought out before I executed it . . . But even though I instinctively knew I was getting too close to the tree . . the only tall tree near me . . I had the presence of mind to be checking my altitude before arriving . . .but failed to account for a couple of seconds of sun in my eyes . . .This is now an rapid reaction I will practice until it is instilled as automatic. . . If I am ever unsure I am high enough . . my first instinct should be UP! . . not "I wonder if I'm high enough?"

The ONLY TREE! . . from where I was standing as it passed right to left at 94.5ft
 

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Thanks David. I know we all appreciate your posting. To bad about your drone. I am already beginning to think as to what would I do in your situation, up and back! I think I'll even practice it tomorrow, weather permitting.
Thanks,
Jim
WA5TEF
 
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Thanks David. I know we all appreciate your posting. To bad about your drone. I am already beginning to think as to what would I do in your situation, up and back! I think I'll even practice it tomorrow, weather permitting.
Thanks,
Jim
WA5TEF
I'll be practicing it too . . soon as I get it replaced . . . and see how aggressively I can make those control inputs without over correcting and making things worse . . before I adopt it as an "instinctive reaction"
 
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Followup after getting my machine back from DJI . . . two firmware upgrades later we are all ready to go. Brand new bird it looks like. . . weather has been awful all week so will not get to fly it for few days yet. Still, DJI came through with a DJI Care Refresh that looks and acts good as new!
 
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Great!! You are fortunate to get your drone back. Did you check serial numbers? You may have been sent a refurbished or even maybe a new one! Thanks for the followup you sent. keep us posted as to your flights, etc.
Thanks,
Jim
WA5TEF
 
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Appreciate the detailed synopsis of your tragic flight. Glad you got your drone back so quickly.
 
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Great!! You are fortunate to get your drone back. Did you check serial numbers? You may have been sent a refurbished or even maybe a new one! Thanks for the followup you sent. keep us posted as to your flights, etc.
Thanks,
Jim
WA5TEF
It is a DIFFERENT serial number . . in fact it looks brand new . . except no clear plastic or peal off labels you get with a new one. . . nary a scratch, smudge or even a finger print. Looks and acts new including start up and camera systems checkout after the two firmware upgrades. I'll come back with a full flight report soon as the weather clears here in Southern Ontario. It was gone from 3 April to 4 May so not too bad really. Given the bag of parts I sent back though I doubt it took them 3 weeks to diagnose.Not complaining, their DJI Care Refresh works as advertised.

Even when I sent my Mavic back for "grindy motors" when it picked up some grit on landing they turned it around fairly quickly and without any push back. Basically I got back a new machine that behaves exactly like the one I was flying before the incident. This has saved me two machines now at the cost of less than $210 each including shipping, Definitely recommended, even for experienced flyers . . Good system! . .
 
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I had a panic situation with my P3 and lost SA while trying to get it home and down low fast. It made it back, but when I viewed the video, it barley missed a couple trees--flew right next to them. Could have been a disaster.

That's why I now keep high altitude whenever possible.

 
Joined
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I had a panic situation with my P3 and lost SA while trying to get it home and down low fast. It made it back, but when I viewed the video, it barley missed a couple trees--flew right next to them. Could have been a disaster.

That's why I now keep high altitude whenever possible.

WOAH . . . that WAS close! . . . very lucky indeed.
 
C

Crack The Sky

Guest
Worst fears realized yesterday!! . . . I'm a pretty experienced flyer . . . retired career helicopter pilot with thousands of hours flying low level . . and now 250+ UAV missions in the past year . . you'd think I would know. Coming back to shore from a run in SPORT mode out over the bay, at what I knew and could see by the display was around 120ft+ Altitude. . . . as it crossed right to left about 20-30min front of me . . . I was blinded momentarily by the sun so . . . I looked down at the display quickly to see what the altitude actually was . . Knowing I was fairly low but expecting to be high enough to clear the 1 tall tree to my left . . .before I could focus on the DJIGO4 screen . . WHACK! . . just clipped the top bare branches of the only tall tree around . . and with at least 2 maybe 3 blades blown off it tumbled and hit the ground hard . . . broke just about everything. . . and continued to spin the bladeless motors. . . finally I issued a CSC and it stopped vibrating as I picked it up . .in pieces

HOW COULD THAT HAPPEN ?. . .The telemetry says it hit at 94.5 ft so I obviously was not above 120ft like I thought. The angle looked like I was passing behind and above the tree . . but depth perception is pretty low especially when looking upSun, into a bright sky.

CONTRIBUTING FACTORS:
1. It was cold and I was wearing special touch sensitive gloves but may NOT have been been able to feel the light pressure if I was exerting by resting my left thumb on the stick . . even a slight back pressure probably caused the bird to drop 10-20 ft in the 30-40 second prior to the event.
2. I was VLOS (Visual Line of Sight) not FPV (First Person View) . . if I had been flying just using the FPV camera view I would have noticed I was heading directly toward the tree not passing by it. . . here in Canada FPV flying is not allowed . . it means "no goggles" . . but technically means you should be VLOS looking at the drone not the display at all times.
3. Lack of a pre-planned IMMEDIATE RESPONSE. Flying helicopters in the military we often practiced what is the first automatic reaction to an emergency. . . like if you have an engine failure your immediate response should be to lower the collective and preserve rotor rpm . . you should not have to think about it . . it should be just an instinctive reaction. . . . .
4. Depth perception when looking into the sun or bright sky. Lack of shadows and a bright featureless sky background gives little visual aid in estimating distance or height.
5. Poor path panning. High rate of angular movement (due to close-in pass) leads to lack of situational awareness if you're visual field passes through 180 degrees in less than a second. It takes more than a second or two to become familiar of a rapidly changed scene . . unless your brain gets there before the aircraft as it should.

Being unexpectedly blinded by the sun but fully aware I was approaching obstacles at speed what is the best reaction? . . slow down yes . . but that takes time when not anticipated. You could instinctively turn away from the shoreline but at a critical moment you might just as likely hit something else. The only likely safe place is above you and so the immediate response SHOULD have been to slow down but immediately apply FULL UP command and head for the sky. . . . I waited barely a second too long by thinking "hey that looks a bit low . . woah! sun in the eyes . . . let's look at the display and see what it says" . . WRONG! . . .immediate reaction to my perception of a threat should have been back on the right stick and FULL POWER.on the left . . just for a full second or 2, so I would head for clean air above and give myself time to think and confirm there may be a potential threat here.

Yes this would likely not have happened anyway, had my decision to fly back towards home in SPORT mode been better thought out before I executed it . . . But even though I instinctively knew I was getting too close to the tree . . the only tall tree near me . . I had the presence of mind to be checking my altitude before arriving . . .but failed to account for a couple of seconds of sun in my eyes . . .This is now an rapid reaction I will practice until it is instilled as automatic. . . If I am ever unsure I am high enough . . my first instinct should be UP! . . not "I wonder if I'm high enough?"

The ONLY TREE! . . from where I was standing as it passed right to left at 94.5ft
Excellent self-critique. Thanks for sharing.
 
C

Crack The Sky

Guest
I had a panic situation with my P3 and lost SA while trying to get it home and down low fast. It made it back, but when I viewed the video, it barley missed a couple trees--flew right next to them. Could have been a disaster.

That's why I now keep high altitude whenever possible.

Well yea. You're flying backwards. How are you not going to hit something, eventually?
 

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