"My boss wants us to fly airplanes under FAR91 with small defects such as nav lights, inop radios etc, which is not a problem. But he wants the pilots to record those defects in the airplane deficiency log with the pilot name, certificate number and a statement that the airplane is safe to fly."
What, NOT A PROBLEM????? Those are things you keep to yourself or call the FAA over.
Must still comply with MMEL and have a MEL auth for part 91 to my knowledge, believe you would need a ferry permit to deviate from items listed in MEL or CDL.
Maintenance or pilot could determine safety of flight issues not covered by the doccuments... In the case of deciding the difference between cosmetic and structural damage with the aid of amm/srm etc. You should also have a NEF program for part 91 to cover most chapter 25 items.
But components, no. I think they could fly as an open log item as long as they comply with the MEL you can find a MMEL online.
Where would pilot A stand if pilot B, using the statement of pilot A as justification, got into trouble if the flight was not in fact safe without that piece of equipment and he did not make it back?
A pilot is not authorized to sign off a log page only generate one and make the decision if the aircraft is airworthy under part 91 with MMEL at hand. Follow the MEL you may be able to carry an open log under part 91 of items not restricting flight.
Call your local FSDO for proper clarification.
I googled part 91/mmel and got dizzy reading some of the publications.
Understand you are in a pinch but you should confront your boss, call the FAA (whistleblowers protection) or quit.....