Date: 201704
Local time of day: 1201-1800
Location: HPN.Airport, NY
Flight conditions: VMC
Weather elements / visibility: Turbulence; 10
Light: Daylight
Aircraft: Bonanza 36
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Descent
Airspace: Class E N90
ATC / advisory: TRACON N90
Aircraft component: Door
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Workload; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Aircraft; Weather
Primary problem: Aircraft

Narrative: VMC conditions but filed IFR because of over Canada route to White Plains; New York; HPN. Most of flight in level cruise at 11;000 feet. On descent into HPN moderate to worse turbulence. Other planes in area started making repots of bad turbulence. Had been given NOBBI FIVE DCY transition but then at NOBBI given direct route to another point I can't remember because just about then the copilot i.e. the front door on a Bonanza came open in flight. There was one passenger in the co-pilot seat and one passenger in the aft seat. It was very loud and there was a great deal of static or wind noise in my headset so I could not hear New York Center (it may have been NY Approach). Because of this and because I had HPN in sight; I [advised ATC] and turned directly toward HPN; and transmitted my intentions. Eventually I was able to hear ATC and was cleared direct to HPN and to land at any runway. On contact with HPN Tower I was cleared to enter a right downwind for 34 and landed without incident. 34 was the active runway. This is not the first time I've had trouble with the co-pilot door opening in flight. It has happened [twice in the past two years]. After each incident I've had the door gone over by an A&P. At each annual I have the door checked. At each flight I am the only one to close the door. I make everyone in the plane be quiet and I focus on closing the door and making sure it is fully closed. I've read everything there is to read about Bonanza doors. I feel the design is defective. There is simply no way to be sure the door is closed and that all the door lock pins are properly seated. I warn all passengers prior to each flight that the door may come open and that they should not panic and that the plane will fly just fine. As for what else I could have done differently; there was an AIRMENT for moderate turbulence below 8;000 feet for the HPN area but there were no pilot reports of turbulence. The turbulence seemed to build as I entered the area. Because I'm paranoid about the door during the descent I looked at the upper rear corner of the door and could see sunlight. That's never a good sign. I suspect the top latch pin/hook did not fully engage when I closed the door and one good bump was enough to pop open the door. I have the annuals performed by a premier Beech Bonanza/Baron service center. The door problems have been very frustrating.




Synopsis: BE36 pilot reported the front passenger door opened in flight due to turbulence while descending.