14 CFR § 142.49

A certificate holder may allow an instructor to provide:

Instruction for each curriculum for which that instructor is qualified.

Testing and checking for which that instructor is qualified.

Instruction, testing, and checking intended to satisfy the requirements of any part of this chapter.

A training center whose instructor or evaluator is designated in accordance with the requirements of this subpart to conduct training, testing, or checking in qualified and approved flight training equipment, may allow its instructor or evaluator to give endorsements required by part 61 of this chapter if that instructor or evaluator is authorized by the Administrator to instruct or evaluate in a part 142 curriculum that requires such endorsements.

A training center may not allow an instructor to—

Excluding briefings and debriefings, conduct more than 8 hours of instruction in any 24-consecutive-hour period;

Provide flight training equipment instruction unless that instructor meets the requirements of § 142.53 (a)(1) through (a)(4), and § 142.53(b), as applicable; or

Provide flight instruction in an aircraft unless that instructor—

Meets the requirements of § 142.53(a)(1), (a)(2), and (a)(5);

Is qualified and authorized in accordance with subpart H of part 61 of this chapter;

Holds certificates and ratings specified by part 61 of this chapter appropriate to the category, class, and type aircraft in which instructing;

If instructing or evaluating in an aircraft in flight while serving as a required crewmember, holds at least a valid second class medical certificate; and

Meets the recency of experience requirements of part 61 of this chapter.