To: Nick Lappos,
I beg to differ with you regarding on what subterfuge aircraft companies enter into when selling a design to the military or to a civilian operator. In my line of work I get to see all of it. By the time it gets to people like yourself the design good or bad is cast in concrete and you have to work with it. Sometimes the problems manifest themselves in a short period and in other cases the design has to accumulate many hours before the problems manifest themselves. A perfect example of this is the fail safe design of the S76 rotor blade.
I have been in this line of work since 1968 and I have been involved in aircraft since 1949. I would say that this provides a good perspective as to what is good and what is bad.
Regarding your two friends at Agusta and Westland they had absolutely nothing to do with the preparation of the product assurance documents and as I stated above they had to work with the design that was presented for testing. Unluckily for those engineers and technicians at Agusta that lost their lives the design was defective and nobody was aware of it because the stated failure among many others were removed from the FMEA and consequently never were considered in the safety analysis.
Now, let’s get on the subject of how honest aircraft companies are when dealing with a customer when there is an accident. Although the following can be representative of any airframe manufacturer it is a story that happened at the Flying S the same company you work for. Put your self in the position of the two investigators from the Navy or, better still in the places of the crew involved in the accident.
I was a techrep for Sikorsky probably before you were born.
Our in plant education consisted of fourteen weeks of classroom study and eight to ten months in the shop. While in the shop, we did everything. We punched rivets, installed hydraulic systems and electrical systems. We built up and installed rotor blades, rotor heads, gearboxes, and clutches, fuel tanks and, flight control components. If it went into the three models being built by Sikorsky our group had our hands in it or on it.
It was during the shop program that the writer became aware of what is to follow. The writer had just completed a two-week stint in the gearbox and rotor head section. The trainees were usually asked to leave because they were building these units faster that the shop personnel. The writer moved into the adjacent group that built tail rotor and intermediate gearboxes, as well as mechanical and hydromechanical clutches. Shortly after moving into this area, the writer became aware of a hushed conversation between the shop foreman, the plant manager and two U.S. Navy Officers. They were reviewing some paper work. They would go off to the transmission run-in room and upon returning they would again look at the papers. They seemed to be in an argument, but they kept their voices down so as not to be overheard. Finally the group broke up and the two Navy officers left. They seemed to be in a heated conversation.
It took a while, but the writer eventually got the full picture. Actually it was two pictures. One was the company picture the other was the Navy picture. The Navy had recently lost a brand new helicopter. It crashed in San Diego Bay after losing its tail rotor. The three crewmen died in the crash. Within hours, the Navy recovered the helicopter with the tail rotor gearbox still attached. They also recovered the tail rotor, which was almost intact.
When the accident investigation began, the tail rotor gearbox was opened. The investigators found that a critical part was missing. It was thought that it may have fallen out of position and got entrained in the gear mesh. Closer examination proved this to be a wrong conclusion. The gears were unmarked and there was no debris inside the gearbox. The finding of the accident investigation team was that the snap ring had never been installed which lead to the accident. That is what the Navy Officers were saying, and the other two men were denying it. The papers they were looking at, were the inspection records for the tail rotor gearbox.
By the time the writer was to move to his next workstation, he had developed his own conclusions, which were in total agreement with the Navy investigation team.
As each element is installed the technician and the inspector sign it off. Then the next part is installed with the same double sign-off. On several occasions the writer saw the technicians install several parts without signing the work off. They would then sign off the work and the inspector would buy the work off on their say so, totally in violation of quality control regulations. This happened many times. In some cases, the gearboxes were closed up before the work was signed off. After the gearboxes are complete and all signed off they are sent to the run in room where they are placed under load and run in for an hour or so.
Under normal condition, the gearbox would be returned to the work area to be partially disassembled to allow the gear mesh pattern to be checked. Some times they would luck out when the pattern was found to be O.K. If the mesh pattern were unacceptable, it would normally be corrected by the second run. This gearbox was returned, not for a check of the gear mesh, but because it was leaking.
The gearbox was partially disassembled to install a new gasket. It was then returned to the run in room. Instead of creating new paper work, the technician’s double stamped the existing paper work. It took three more tries to fix the leak. Each time the gearbox was reassembled, a stamp would be made on the paper work. This time the gearbox didn’t leak and after the run in the gear mesh was checked. To do this, the end of the gearbox, which is held in place by several bolts, is removed. This provides a direct view of the snap ring. The only thing that was of interest at that time, was the gear mesh. The Navy postulated that they didn’t look at the lock nut, which was supposedly held in place by the snap ring. When the end closure was reinstalled and bolted in place all of that work was double stamped.
Some of the tasks on the paper work had as many as fourteen stamps, including the inspectors’ stamps. The technician and the inspector double stamped the end cap removal/replacement. It was the company’s argument that when the end plate was removed the technician not only checked the gear mesh pattern he also verified that the snap ring was in place. That may be true and if it was true, why didn’t the technician double stamp those tasks as well. Another point to ponder was that the two technicians were given time off with pay and the inspector was moved to another department during the period that the Navy Officers were in the plant. The two people that made the argument for the company had absolutely no knowledge of what happened and those people that did were not made available to answer the questions of the two Navy personnel.
Three good men died because of an error made by those technicians. However, it could have been worse. When that gearbox was signed off, it was painted and placed in free stock. As free stock it could have been placed on a commercial or U.S. Army version of the Navy helicopter. These helicopters carry a crew of two and up to twelve passengers.
[ 22 July 2001: Message edited by: Lu Zuckerman ]