Had a very close call yesterday, and still trying to process it and keep replaying it in my mind.
Plane has Dynon Skyview touch, backup Garmin G5, about 900 hours and 11 years flying. Spends about 30-40 nights a year outside while traveling, and the rest of the time in a climate controlled hangar. About 3 months ago, on takeoff the AOA alarm starts beeping just as I pitch for climb. I am relatively light with the 390, so there is little chance of a stall on takeoff but I lower the nose regardless. Land for fuel 30 minutes later, and the AOA is beeping at me the whole time in the pattern. Im very familiar with the pattern sight picture, but keep my speed up anyway. Pull the aft baggage panel and everything looks connected. Ended up lowering the AOA volume and continuing on. Everything else appears normal. Airspeed seems to be working normally, but he Dynon AP is having pitch issues. Constantly hunting altitudes.
Re calibrate the AOA, do the AP calibration procedure a couple times. Things working normal ish for a while. Flew to NY from NV and everything working perfectly. Almost too good. Spent a few nights out in the rain before I put it in a hangar in NY. Do several local flights while in NY, and practice short field landings since we re landing at a friends 1700’ grass strip. The AOA was going off at 90KTS in the pattern. Went around and turned the volume to the AOA off. Did a few landings. Was concentrating more on the sight picture than the panel. Airspeed seems to be working properly, but on short final my eyes are outside so don’t notice any issues.
On 1 mile final at the 850msl grass strip in VA, the plane felt mushy, but was still at 75KTS. Dynon and G5 rereading the same. Kept slowing to get down to 70, but the pitch was way too high. Got this really bad feeling and added power. In hindsight sight, was starting to stall over the trees, 1/2 mile out. Went around for another try. Switched the ALT static source at pattern altitude, and the airspeed jumped up 30Kts. Switched it back closed and everything working normally again. In hindsight, I just equalized the pressure in the static line. Landing attempt #2, we never got below 75KTS indicated on final but still felt mushy. The plane started to stall just as crossing the runway threshold but still 10-20 feet off the ground. Added full power, to arrest the fall, and hit the runway. Was able to maintain directional control, and pulled the power when I realized we were on the ground and didn’t bounce. Minimal damage to the plane, and no prop strike. Tie her down and try to come up with a plan.
Today, start pulling panels, looking for breaks in static or pitot lines. In the tail section, I see some discoloration in the static lines about 3-4” up from the ports. There is NO loop to trap water. Bends up just near the ports. The discoloration has been there the last couple of inspections but figured the stock Vans tubing was getting old, and would come up with a plan to change it. Disconnected the line from the AHRS, and couldn’t blow through it. Compressed air was able to clear it after a few tries. Ended up cutting the tubing out and replacing it. It has some yellow crusty substance at the curve for a few inches. Totally clear near the ports, and further up. The pitot lines are all the high quality lines from Stein, but the static lines aft of the baggage bulkhead are the stock Vans vinyl lines, and refrigerator water lines included with the kit.
Im sure this will correct the airspeed errors, and the AP should return to normal working order. Unfortunately, we came very close to an accident before the problem was found.
Plane has Dynon Skyview touch, backup Garmin G5, about 900 hours and 11 years flying. Spends about 30-40 nights a year outside while traveling, and the rest of the time in a climate controlled hangar. About 3 months ago, on takeoff the AOA alarm starts beeping just as I pitch for climb. I am relatively light with the 390, so there is little chance of a stall on takeoff but I lower the nose regardless. Land for fuel 30 minutes later, and the AOA is beeping at me the whole time in the pattern. Im very familiar with the pattern sight picture, but keep my speed up anyway. Pull the aft baggage panel and everything looks connected. Ended up lowering the AOA volume and continuing on. Everything else appears normal. Airspeed seems to be working normally, but he Dynon AP is having pitch issues. Constantly hunting altitudes.
Re calibrate the AOA, do the AP calibration procedure a couple times. Things working normal ish for a while. Flew to NY from NV and everything working perfectly. Almost too good. Spent a few nights out in the rain before I put it in a hangar in NY. Do several local flights while in NY, and practice short field landings since we re landing at a friends 1700’ grass strip. The AOA was going off at 90KTS in the pattern. Went around and turned the volume to the AOA off. Did a few landings. Was concentrating more on the sight picture than the panel. Airspeed seems to be working properly, but on short final my eyes are outside so don’t notice any issues.
On 1 mile final at the 850msl grass strip in VA, the plane felt mushy, but was still at 75KTS. Dynon and G5 rereading the same. Kept slowing to get down to 70, but the pitch was way too high. Got this really bad feeling and added power. In hindsight sight, was starting to stall over the trees, 1/2 mile out. Went around for another try. Switched the ALT static source at pattern altitude, and the airspeed jumped up 30Kts. Switched it back closed and everything working normally again. In hindsight, I just equalized the pressure in the static line. Landing attempt #2, we never got below 75KTS indicated on final but still felt mushy. The plane started to stall just as crossing the runway threshold but still 10-20 feet off the ground. Added full power, to arrest the fall, and hit the runway. Was able to maintain directional control, and pulled the power when I realized we were on the ground and didn’t bounce. Minimal damage to the plane, and no prop strike. Tie her down and try to come up with a plan.
Today, start pulling panels, looking for breaks in static or pitot lines. In the tail section, I see some discoloration in the static lines about 3-4” up from the ports. There is NO loop to trap water. Bends up just near the ports. The discoloration has been there the last couple of inspections but figured the stock Vans tubing was getting old, and would come up with a plan to change it. Disconnected the line from the AHRS, and couldn’t blow through it. Compressed air was able to clear it after a few tries. Ended up cutting the tubing out and replacing it. It has some yellow crusty substance at the curve for a few inches. Totally clear near the ports, and further up. The pitot lines are all the high quality lines from Stein, but the static lines aft of the baggage bulkhead are the stock Vans vinyl lines, and refrigerator water lines included with the kit.
Im sure this will correct the airspeed errors, and the AP should return to normal working order. Unfortunately, we came very close to an accident before the problem was found.
