Flight 401 - Possible Explanation

According to an excerpt from the book, The Ghost of Flight 401, by John G. Fuller, there is an explanation of how this tragedy actually took place.

First, the crew was on final decent when they discovered that the front landing gear light was not coming on to show that the front landing gear was locked down and ready for landing. Therefore, they radioed the tower and told them that they needed to circle around to make sure that this was just not a burnt out light or in fact they had a problem with the front landing gear.

The tower gave them the orders to climb to 2000 feet and circle around the airport, in which they did. Once at the altitude, they set the auto pilot and began to work on the light.

Officer Repo (The flight engineer) went down into the crawl space below the cock-pit (into the hell hole) to check on the gear. While the rest of the grew were testing out the light and talking with him through the open door.

At some point, the auto-pilot was pumped, turned-off, or failed and the plane began to descend.

In the book, it describe that the altitude gauges between Captain Loft and the co-pilot the first officer, Albert John Stockstill where not in sync or (mismatched); whereas, according to Stockstill's gauge the plane was holding at 2000 feet while Captain Loft's gauge actually showed the decent. The problem was that Captain Loft was busy talking with Repo and everyone else in the cockpit and not paying attention to his gauge, which in reality, the decent was so slight and the plane was on auto pilot, and on top of that the co-pilot had a gauge that showed the plane was fine.

There was an alarm that went off show that the plain was at a low altitude; however, the design at the time only had the alarm at the engineer's station. The problem was, the engineer was downstairs in the hell hole.

This leave the question. Was the cause of the crash due to pilot error or mechanical failure and poor design? The official investigation was that it was pilot error.