Virtually every place I have worked for over the years has engaged in team instruction. It could be a formal phase check with a different instructor. If could be a way of keeping the student on track when their primary CFI was out sick, on a charter, or otherwise unavailable. In other cases, it can be used to get a student through a learning plateau. Its a great way to foster a well rounded student through diversity of instructional techniques.
Communication and consistancy are key. As CFI’s we all have different ways of doing things, and in some cases, we may even consider one CFI’s approach to be totally wrong… However, we have to take a big picture view of this, and that is consistency for the students sake, even if it goes against our personal opinions and bias.
For example, I have always taken a dim view of 30 minute preflights. Other instructors seem to be pleased with such an approach. Now, if I’m working at a school that advocates a 30 minute preflight, then thats what I will teach to my primary students. If I’m working at a school that has a no lean policy below 5000 feet, then I will teach leaning as an academic exercise only. I will however take up these somewhat unusual practices with the chief instructor, or the owner in private. Their may be reasons why they wish to do these things. Such reasons may only be old wives tails, or they may be valid given other extenuating factors. Either way, they are the one paying the tab, and professionalism suggests I follow their lead even if I disagree. Of course this does not preclude going along with blatantly unsafe operating practices, nor breaking the law in order to please the boss.
The reason for this is not to be a wimp, but to provide a consistant and unified instructional environment for the student. Once they have their certificate or rating, at that time, if the owner of the flight school agrees, we can go into different ways of approaching flying. I think it is critical for every CFI candidate to be exposed to a wide variety of instructional and procedural techniques.