Narrative:

After takeoff the right main landing gear did not retract. ATC also notified us that it was still down.both the sic and I preflighted the aircraft exterior simultaneously. I reached for the pin from behind the right main gear and did not feel it. I thought first officer (first officer) had already pulled it. This particular aircraft has extremely large and heavy gear-pin-flags and I'm used to grabbing for them and feeling my way up to the pin. This is much easier on the knees than getting them from the front. It was very windy outside and it must have blown up into the wheel-well and out of obvious sight. I also did a walk-around checking the fuel cap and pins before closing the door. When I got into the the plane; first officer had the pins laid out next to their respective bags and I put the bags away. Evidently; I didn't count very well. The flight was a relatively short one and we continued to destination at 250 knots and landed without further incident. We did run the abnormal checklist on the way. Not-seeing or feeling a very large flag is not enough to verify the actual pin has been pulled. I had heard of others doing this but I never thought it would happen to me. I will also do a much better job of counting the pins. I put them in the bag and put them away and obviously didn't do a good job of counting. This particular bag looks very full since the flags are so large and bulky.

Google
 

Original NASA ASRS Text

Title: Challenger 300 Captain reported the right main landing gear did not retract after takeoff due to a gear pin not being pulled during preflight. The crew decided to continue to the destination flying at 250 knots and landed uneventfully.

Narrative: After takeoff the right main landing gear did not retract. ATC also notified us that it was still down.Both the SIC and I preflighted the aircraft exterior simultaneously. I reached for the pin from behind the right main gear and did not feel it. I thought First Officer (FO) had already pulled it. This particular aircraft has extremely large and heavy gear-pin-flags and I'm used to grabbing for them and feeling my way up to the pin. This is much easier on the knees than getting them from the front. It was very windy outside and it must have blown up into the wheel-well and out of obvious sight. I also did a walk-around checking the fuel cap and pins before closing the door. When I got into the the plane; FO had the pins laid out next to their respective bags and I put the bags away. Evidently; I didn't count very well. The flight was a relatively short one and we continued to destination at 250 knots and landed without further incident. We did run the abnormal checklist on the way. Not-seeing or feeling a very large flag is not enough to verify the actual pin has been pulled. I had heard of others doing this but I never thought it would happen to me. I will also do a much better job of counting the pins. I put them in the bag and put them away and obviously didn't do a good job of counting. This particular bag looks very full since the flags are so large and bulky.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.