Pilot Production can be used to produce actual production units for the purposes of testing your manufacturing process design and to gain regulatory approval.  

With the initial Manufacturing Process Design complete and the Test Fixtures and Jigs available, the Pilot Production run can be used to prove the production process is sufficient and outputs the intended Product. 

The Pilot Product is designed to yield true production units with the exception that the units are built under a controlled, but not proven process.  Once the manufacturing process is verified (and possibly validated), then the Pilot units can be said to be true production units and therefore suitable for sale. 

The Pilot Production run must be at least a minimum of units that: 

1. Can challenge the process properly.  This is usually a few dozen units, but it is dependent on the type of product and the degree of difficulty and risk.  See the section on Process V&V for more detail.  Some of the units may be scrap at the end of V&V testing.
2. Will yield a group of units that can be used for Regulatory Approval.  See the section on Regulatory Approval for more detail.  These units will be returned after Regulatory, but some may be damaged and may not be suitable for further use.
3. Will yield a group of units for use as Sales Demonstration devices or Training devices, depending on customer requirements.  If you think stress screening and drop testing is hard on a product, try giving one to a Salesperson.   

There is a bit of a challenge to setting a number for the Pilot Production because of the risks associated with Regulatory Testing and Process V&V. 

If the Regulatory Testing is completed and you have permission to mark the product, you must bring the existing Pilot units up to the design of the approved product – including mitigation – before they can be marked.  If there is mitigation for a failure, that must also be considered in the Process Design and some of the V&V may have to be repeated. 

Be aware that there may be some iteration between the Product Design / Process Design / Regulatory Approval before all three are satisfied with a single design and process.  There are strategies to minimize the iterations.