I know the Commercial Pilot ACS has the matrices in the back for adding to your existing CP SEL certificate. But the way it's presented doesn't get me to 100% understanding....
Can someone explain to this Texas Aggie what happens during the oral and flight part of the Checkride that's different than the SEL ride? What subjects are covered and what maneuvers are performed in flight.
Oh, and on the same check ride flight, can I do the required items to add AMEL-Instrument to my list of ratings? If yes, what are these items?
Mike,
As you suggested, all of the answers to your questions can be found in the Commercial Pilot - Airplane ACS. Specifically, the Task table found on page A-14, "Addition of an Airplane Multiengine Land Rating to an existing Commercial Pilot Certificate."
Per the table, the oral portion of the practical test will only involve I.F., "Performance and Limitations," and I.G., "Operation of Systems."
Although the ACS allows for the examiner to select only one Knowledge element and one Risk Management for each Task (A-8), in the case of multiengine add-on rating, myself and most examiners I know will cover all of them (exception would be systems with which the aircraft is not equipped). It would be difficult to satisfactorily meet the Objectives and evaluate all of the Skills listed in both tasks without doing so. CA.I.F.K3, "Aerodynamics," is a comprehensive area of discussion as well.
Even with thorough coverage of these two areas, this oral tends to be on the short side, usually 1.3 to 1.5 hours for a well-prepared applicant, at least in my experience. Essentially, you need to understand and explain the systems of the multi-engine airplane presented for the checkride, demonstrate the use of manufacturer-provided performance charts and tables, have a thorough understanding of aerodynamics as they apply to multi-engine airplane flying, and understand how to deal with system failures and emergencies.
For the flight portion, you can also use the Task Table, and/or simply note which tasks have "AMEL" or are not restricted to specific classes (i.e. ASEL/ASES only).
You may include instrument rating privileges by accomplishing Task X.C and X.D. (p. A-16)
Hope this helps,