Dividing the floor

Looking forward from an area abeam the forward cabin door. Throttle quadrant, control yokes and rudder pedals were all left in place to facilitate future decisions about how to configure the underside of the forward floor.

Having removed almost everything above the waterline, I’m turning my attention to the remaining floor section, which one recent visitor said “looks more like a boat than anything else.”

A very leaky ‘boat’ is all that remains after the walls came off.

The strategy with this task is to divide the floor into pieces that are small enough to get through my basement door, taking advantage of the original Boeing structure to leave matched holes that will allow for realignment later.

The floor of the lav. The floor aft of the cockpit door is covered with composite panels, easy enough to remove once the incredibly thick, incredibly sticky tape is removed. Orange area is the part underneath the sink, flimsy plastic because no one ever stands on it.

After some investigation and feasibility experiments with drilling out various rivets, I settled on a line parallel with the lateral axis of the aircraft, about ten inches forward of the cockpit door frame. Underlying this line is a heavy spar that is attached to the aft part of the floor by six lighter spars that run longitudinally. Fortunately these lighter spars were secured to the heavy one with aluminum rivets, thankfully easy to drill out given the awkward spaces in which I had to use the right angle drill. I’m still looking for a more efficient way to drill out the steel huck rivets that continue to slow me down. An online hint to use a masonry drill bit did not seem to be much faster than the standard black oxide.

After drilling out the rivets attaching the longitudinal spars to the heavy lateral spars.

The dismantling continues

It’s been way too long since I updated this blog, but I have actually been busy making progress. The cockpit is now cut down to the flight deck floor, also known as the water line. To accomplish this I divided the structure above the floor into seven major pieces, all with the goal of preserving the geometry of the windows and doors. As I discussed in a previous post, I used custom fabricated angle brackets with pre-punched holes that were put in place with cleco fasteners prior to dividing each section. These brackets were labelled according to their location as unfortunately there is some variation in the location of the pre-punched holes. After drilling all the appropriate mounting holes in the original structure, the clecos and brackets were removed and the cutting process began.

The biggest challenge in making many of the cuts in the metal was finding a tool that was small enough to fit in the available spaces. The structure designed by Boeing becomes increasingly more robust as you move forward through the cockpit, and unfortunately the space also narrows simultaneously. I used a combination of a Ridgid 4.5 inch electric angle grinder and a reciprocating saw with various blades to make the cuts. A double cut saw from Harbor Freight also came in handy for some of the thicker pieces.

After cutting the aft part of the top off, I lifted it off the structure with ropes run over the ceiling spars in the hangar.

The resulting segments were awkward to move around but not especially heavy, probably on the order of about 100 pounds each. To make things safer and easier, I took advantage of a steel girder running across the ceiling in the hangar, and used a set of ropes to lift the pieces off the structure and slowly lower them to the floor. Once on the floor, the pieces were easy to slide around.

In order to preserve the geometry of the windows, I elected to remove the top of the cockpit in one piece. Red circles indicate predrilled holes for mounting custom made alignment brackets. This will preserve the geometry of the windows and maintain the proper angle of the overhead panel.

One major decision involved the roof of the forward part of the flight deck, which is relatively heavy with many thick  spars. As I now possess a complete set of real Boeing windows, I wanted to make sure that the window geometry was maintained, especially for the sliding P2 windows. Another goal was to preserve the positions of  the mounting brackets for  the overhead panels. I determined that the best way to satisfy both requirements was to remove the top as a single piece, cutting about two thirds of the way up the window pillars, with the exception of the center, which was cut at the top. These locations were chosen both to meet design requirements as well as for convenience of cutting.

After removing the top, the next decision was how to divide the remaining portion into manageable pieces. 


Following top removal. The galley remains in one piece at the rear of the trailer.
The top of the cockpit, successfully relocated to my basement.Note sliding P2 window track visible in the P3 window opening.

The removed top fit easily in the bed of my pickup truck, and was moved into my basement with the help of my good friend Miguel. Putting it back into place will require a crew of at least four of us.

After removing the instrument panel and CDU bay, it was time to make some important decisions about how to divide the remaining structure. Note the thick structure.

The next few weeks were taken up with identifying all the places the instrument panel and CDU bay were connected to the structure. This was removed as one piece, intact but not without some minor damage from the process.

Having exposed the structure, it was time to pick some lines to cut up what remained. It initially seemed appealing to make vertical cuts just under the window pillars between the P1 and P2 windows, but when the structure was fully revealed it became apparent that this would involve cutting some of the thickest parts in the whole setup.

Practical considerations led to choosing a vertical line aligned with the outer edge of the FO's left side rudder pedal.

Selecting a different line closer to the longitudinal axis of the aircraft led to a much easier cut that preserved the structure. The hardest part of removing these outer pieces proved to be cutting the spars along the floor line, several of which were in very tight spaces.

After making all the cuts, the FO side separates with a little coercion.

Having completed all of those cuts, the sides came off relatively easily and were lowered onto the floor with ropes.

After separation, the FO side of the forward cockpit rests on the floor of the hangar.

This left the center section, which was cut away from the floor relatively easily. There were only two thick spars to cut in this section, part of the radar mount.

The center section is all that remains after removing both Captain and FO side forward side sections.