§61.35 Knowledge test: Prerequisites and passing grades.
(a) An applicant for a knowledge test must have:
(1) Received an endorsement, if required by this part, from an authorized instructor certifying that the
applicant accomplished the appropriate ground-training or a home-study course required by this part
for the certificate or rating sought and is prepared for the knowledge test;
So something like this is fine:
“I certify that -- John Michael Smith -- has accomplished the appropriate ground training required by 14 CFR Section 61.105((1-13), [or 61.125 ( (1-16) for the commercial written test] as applicable, and is prepared for the “Private Pilot Balloon Hot Air” [or “Commercial Pilot Balloon Hot Air”] knowledge test.” Signed_______________________ Printed name___________________________ Commercial Pilot Certificate No.__________________
Not to confuse things, but that endorsement is not required to be in a logbook, (it just says “received an endorsement,” so a letter is allowable….or it can be tattooed onto his forehead!) though the logbook is the best place to put it because eventually, when the applicant takes the practical test, then a “logbook endorsement” covering the knowledge training is required [see 61.103(d)(1) and 61.123©(1)].
To accompany that endorsement, there must be evidence, in the log book (or some other recording document) that shows training in those areas was accomplished. 61.105 & 61.125 both require the applicant to “receive and log” ground training (or complete a home-study course, instead).