FileMaker Go enables you to use a database created with FileMaker Pro or FileMaker Pro Advanced on an iPad, iPhone or iPod touch. This can be a database that is copied to the mobile device or it can function as a client (via wiFi or 3G) of FileMaker Database that is hosted on a server.
If your engineers will be limited to only adding new records (such as a record of work done on the remote site for billing/payroll purposes), then you can probably get this to work without too much trouble if you choose to invest the time needed to learn how to work with FileMaker and FileMaker Go or hire the services of a consultant to do it for you. The engineers can return to the home office or other site with WiFi or 3G service and then use Import Records to add the new database to the main copy in the office. Uploaded copies of this updated database can then by copied back to the iPad.
If your engineers need to be able to change existing data in the database, then the project gets much more complex as you'd need to develop a system for merging the changes back into the main database without losing some of the changes when one user's changes overwrite those made by another.