The morning in the shop started out well with the completion of the rivets in the front and rear seatbacks and the trimming of the nylon blocks that mount the flap actuator bar. From that point the shop session turned into an exercise in frustration.
The problem started with mounting the flap actuator bar so the second hole in the mounting blocks could be match drilled to the rear cockpit floor and the underlying mid cabin longeron. I tried everything but could not get the two bolts to thread into the existing nutplates that were installed on the longeron some weeks ago. I finally decided to take a break, watch a recorded episode of NCIS, and think through the problem. Finally, I decided to go to the bag of hardware, pull an example of the nutplates in question, and examine it for some defect.
Well, there was a defect all right but it wasn't the nutplates. The hardware bag originally contained four nutplates of similar configuration except two were for AN3 bolts and two were for number 8 screws. I inadvertently installed the wrong two nutplates on the longeron. Now the problem was to remove and reinstall the correct nutuplates in a very tight space.
Well, I corrected the problem but it took some time. To get access the floor had to be removed as did the seat belt attach brackets which are located just above the longeron and problem nutplates. The rivets had to be very carefully drilled out and the new hardware installed. RIveting the correct nutplates was challenge in the tight space. Finally, all the components were reinstalled and the actuator blocks were match drilled. Now it all has to come out again so two more nutplates can be installed on the longerons. Another tedious riveting task!
