Pilot DAR said:
To add to it, light aircraft do not come with MEL's (probably because there is no requirement for one, and people are not willing to pay the cost to create it). So, what does a pilot do when an unserviceable item is found? It's up to the pilot to judge, which puts a lot of responsibility on that pilot.
Not quite true, some do have the equivalent under the heading of 'Kind of Operations Equipment List' or similar in the Limitations section of the POH. The list in the POH for my Bonanza runs to three pages and covers all of the systems and equipment upon which type certification for each kind of operation (VFR Day, VFR Night, IFR Day, IFR Night) was predicated (some fifty items in total). It is prefaced with:
"The systems and equipment listed must be installed and operable for the particular kind of operation indicated unless:
1. The airplane is operated in accordance with a current Minimum Equipment List (MEL) issued by the FAA; or
2. An alternative procedure is provided in the Pilot's Operating Handbook and FAA Approved Flight Manual for the inoperative state of the listed equipment.
Numbers in the Kinds of Operation Equipment List refer to quantities to be operative for the specified condition. The list does not include all equipment that may be required by specific operating rules. It also does not include components obviously required for the airplane to be airworthy, such as wings, empennage, engine, etc."
And for the Bonanza, an operable stall warning horn is listed as mandatory for all four kinds of operations.