TC & PC, More in Depth
I have thought about writing this post for months, but the subject is so tedious, it was easy to put off. The machinations of Vern and his double speak was far more interesting as were other diversions like Brooke Shields. BTW, lest you think I might have overstated her appearance, I added to the Extreme Views post, her photo leaving a Rome Hotel on the way to Tom's wedding. A pretty sharp chick!
Back on topic, the blog is intended to be informative and at times entertaining. But this post is just plain boring though it might help explain some of the problems facing Eclipse as they seek to obtain their Production Certificate and why the window and wing fitting problem is not related to Airworthiness Certificates for the upcoming deliveries.
Type Certification is the responsibility of a regional ACO (Aircraft Certification Office). For the Eclipse, the Ft. Worth ACO. The role of this office is to ensure the applicant (Eclipse) complies with the technical requirements of 14 CFR Part 23, Part 34 and Part 36.
Every part in the airplane will have a discrete number tied to the drawing that creates the part. Also on the drawing will be a "Used On" number or the link to the next assembly drawing where the part is mated to other parts. This sub-assembly feeds a larger one and the process repeated until the major sub-assemblies like wings and fuselages feed into a single drawing, the completed airplane. Known in the industry as the "top drawing", it defines the airplane. Its number and revision level is stated in the Type Data Sheet. The important thing to remember is that each part in the airplane is linked to the "top drawing".
Any change to any drawing must be reviewed as to the significance of the change. Major changes like adding larger tip tanks will result in some level of retesting and re-certification. The new aircraft definition will be reflected by either a new "top drawing" number or a revision to the original. Minor changes can be written off (pencil whipped) by analysis.
This procedure is part of what fossilizes the aircraft industry, changes are not easy and everything is controlled.
With regards to the wing and window problem, it's the ACO's call. They are confident the windows are good for 50 hours and apparently satisfied the bushings in the wing fitting were not installed correctly. The company can fix the windows at their convenience, the operators will need to swap them out at the prescribed intervals.
Whatever spacers were needed adjacent to the bushings could be added and treated as a minor change and written off.
Production Certificates are issued by an FAA MIDO (Manufacturing and Inspection District Office). A PC gives the company authority to inspect each airplane and is intended to ensure that every airplane that is given a Certificate of Airworthiness, is built exactly to the design that was certified by the ACO. To achieve this, the company drafts a Quality Control Manual that describes in detail how the manufacturing process shall operate. Here are some basics:
Let's start with that discrete part mentioned earlier and assume it is a small aluminum sheet metal bracket.
Purchasing orders a quantity of sheet aluminum of a certain thickness. Before the order is issued, QC (Quality Control) has to review and sign off on the P.O. to ensure the material is ordered to the proper specification.
The material is received on the receiving dock, QC checks the material against the P.O., verifies the markings against the material certification documents provided with the aluminum and files the "certs".
The material goes into a controlled stockroom.
Manufacturing control issues an order for let's say 20 of the discrete parts. A planning sheet which exists for the discrete part is produced. It says to go to the stockroom and obtain 20 blanks of a particular size. The operator who pulls the blanks signs his name to the planning sheet, a QC inspector verifies the blanks and signs the planning sheet.
The parts are cut to shape and deburred per instructions on the planning. The operator signs the sheet, the parts are inspected and QC signs as well.
Next the parts are formed. Two more signatures from the operator and QC inspector.
The parts may get heat treated and/or corrosion protection. Again two more signatures on the planning.
Then the batch of 20 parts is part marked with the part number, production control's job number, the date and the inspectors stamp which signifies that every interim step on the planning sheet was bought off and the parts conform to the original drawing. This completed planning sheet now becomes a permanent record for the company.
Next manufacturing control will release an order and a planning sheet to build a sub-assembly for a particular aircraft serial number. One of the first items on the planning will be a list of all the parts needed for the sub-assembly. Our discrete part will get pulled along with the others. The operator will sign off on the planning as will a QC inspector.
The planning will detail step-by-step the assembly instructions, drill out the pilot holes, add nut plates etc. At interim steps, the operator will sign off, the work inspected and signed off by QC. Upon completion, the planning sheet will go into the permanent records related to a specific serial number. And so it goes until a completed airplane rolls off the assembly line.
This process applies to all sub-contractors. Their signed off planning sheets and functional test results must accompany the item they are supplying. The records will either go into general files or files specific to a particular airplane serial number.
The process applies in one form or another to everything that is covered by the "top drawing" from rivets to the engines.
The QC manual will have the company organization chart that will show some level of independence from manufacturing.
The QC manual will identify every device used in the inspection process and provide a tracking number along with a schedule for validating the device.
If an inspector on the shop floor has a six-inch pocket scale he uses to check parts, it must have an engraved tracking number and be periodically checked for condition and accuracy back to the U.S. Bureau of Standards.
Same for pressure gages used to check tire pressure or exotic electronic devices for checking systems.
The QC manual will define how often the assembly jigs should be checked and a procedure will be written for each jig. The equipment used to check the assembly jigs will get periodic checks back to the Bureau of Standards.
Then there is the validation of functionality of systems. Take for instance the landing gear. There will be detailed instructions to place the airplane on jacks, hook up a power cart and cycle the gear so many times, and record cycle times etc. Even pressure gages to check strut and tire pressures will get validated on a regular basis.
Relating this to Vern's recent statements, in his open letter to customers, he talked about two quality escapes. The first "aircraft build instructions" which I assume means his "planning", either for detail parts or for the assemblies was not complete. The second escape was, "clarity of functional test procedure". This probably relates to incomplete system testing before various systems were installed or just after.
What I don't understand is how you go back after the fact and show everything in compliance, but I am sure there is a way. Eclipse is not the first to run into these kinds of problems with the FAA.
On the AIN report, Vern stated that because Eclipse was asking for a PC rather than just an Airworthiness Certificate on an individual airplane, that there was a "more extensive inspection process". I don't know what he is talking about. You demonstrate to the FAA that all the elements are in place in the QC Manual and that they are rigorously followed for the first few airplanes and they award the PC.