So here is exactly how the FAA words it:
 

Sec. 61.63   Additional aircraft ratings (other than airline transport
pilot certificate).

(a) General. To be eligible for an additional aircraft rating to a pilot
certificate, for other than an airline transport pilot certificate, an
applicant must meet the appropriate requirements of this section for the
additional aircraft rating sought.
(b) Additional category rating. An applicant who holds a pilot certificate
and applies to add a category rating to that pilot certificate:
(1) Must have received the required training and possess the aeronautical
experience prescribed by this part that applies to the pilot certificate for
the aircraft category and, if applicable, class rating sought;
(2) Must have an endorsement in his or her logbook or training record from
an authorized instructor, and that endorsement must attest that the applicant
has been found competent in the aeronautical knowledge areas appropriate to
the pilot certificate for the aircraft category and, if applicable, class
rating sought;
(3) Must have an endorsement in his or her logbook or training record from
an authorized instructor, and that endorsement must attest that the applicant
has been found proficient on the areas of operation that are appropriate to
the pilot certificate for the aircraft category and, if applicable, class
rating sought;
(4) Must pass the required practical test that is appropriate to the pilot
certificate for the aircraft category and, if applicable, class rating
sought; and
(5) Need not take an additional knowledge test, provided the applicant
holds an airplane, rotorcraft, powered-lift, or airship rating at that pilot
certificate level.
(c) Additional class rating. Any person who applies for an additional class
rating to be added on a pilot certificate:
(1) Must have an endorsement in his or her logbook or training record from
an authorized instructor and that endorsement must attest that the applicant
has been found competent in the aeronautical knowledge areas appropriate to
the pilot certificate for the aircraft class rating sought;
(2) Must have an endorsement in his or her logbook or training record from
an authorized instructor, and that endorsement must attest that the applicant
has been found proficient in the areas of operation appropriate to the pilot
certificate for the aircraft class rating sought;
(3) Must pass the required practical test that is appropriate to the pilot
certificate for the aircraft class rating sought;
(4) Need not meet the specified training time requirements prescribed by
this part that apply to the pilot certificate for the aircraft class rating
sought unless the person holds a lighter-than-air category rating with a
balloon class rating and is seeking an airship class rating and
(5) Need not take an additional knowledge test, provided the applicant
holds an airplane, rotorcraft, powered-lift, or airship rating at that pilot
certificate level.
(d) Additional type rating. Except as specified in paragraph (d)(7) of this
section, a person who applies for an additional aircraft type rating to be
added on a pilot certificate, or the addition of an aircraft type rating that
is accomplished concurrently with an additional aircraft category or class
rating:
(1) Must hold or concurrently obtain an instrument rating that is
appropriate to the aircraft category, class, or type rating sought;
(2) Must have an endorsement in his or her logbook or training record from
an authorized instructor, and that endorsement must attest that the applicant
has been found competent in the aeronautical knowledge areas appropriate to
the pilot certificate for the aircraft category, class, or type rating
sought;
(3) Must have an endorsement in his or her logbook, or training record from
an authorized instructor, and that endorsement must attest that the applicant
has been found proficient in the areas of operation required for the issuance
of an airline transport pilot certificate for the aircraft category, class,
and type rating sought;
(4) Must pass the required practical test appropriate to the airline
transport pilot certificate for the aircraft category, class, and type rating
sought;
(5) Must perform the practical test in actual or simulated instrument
conditions, unless the aircraft's type certificate makes the aircraft
incapable of operating under instrument flight rules. If the practical test
cannot be accomplished for this reason, the person may obtain a type rating
limited to "VFR only." The "VFR only" limitation may be removed for that
aircraft type when the person passes the practical test in actual or
simulated instrument conditions. When an instrument rating is issued to a
person who holds one or more type ratings, the type ratings on the amended
pilot certificate shall bear the "VFR only" limitation for each aircraft type
rating for which the person has not demonstrated instrument competency;
(6) Need not take an additional knowledge test, provided the applicant
holds an airplane, rotorcraft, powered-lift, or airship rating on their pilot
certificate; and
(7) In the case of a pilot employee of a part 121 or a part 135 certificate
holder, must have--
(i) Met the appropriate requirements of paragraphs (d)(1), (d)(4), and
(d)(5) of this section for the aircraft type rating sought; and
(ii) Received an endorsement in his or her flight training record from the
certificate holder attesting that the applicant has completed the certificate
holder's approved ground and flight training program appropriate to the
aircraft type rating sought.
(e) Use of a flight simulator or, flight training device for an additional
rating in an airplane. The areas of operation required to be performed by
paragraphs (b), (c), and (d) of this section shall be performed as follows:
(1) Except as provided in paragraph (e)(2) of this section, the areas of
operation must be performed in an airplane of the same category, class, and
type, if applicable, as the airplane for which the additional rating is
sought.
(2) Subject to the limitations of paragraph (e)(3) through (e)(12) of this
section, the areas of operation may be performed in a flight simulator or
flight training device that represents the airplane for which the additional
rating is sought.
(3) The use of a flight simulator or flight training device permitted by
paragraph (e)(2) of this section shall be conducted in accordance with an
approved course at a training center certificated under part 142 of this
chapter.
(4) To complete all training and testing (except preflight inspection) for
an additional airplane rating without limitations when using a flight
simulator--
(i) The flight simulator must be qualified and approved as Level C or
Level D; and
(ii) The applicant must meet at least one of the following:
(A) Hold a type rating for a turbojet airplane of the same class of
airplane for which the type rating is sought, or have been appointed by a
military service as a pilot in command of an airplane of the same class of
airplane for which the type rating is sought, if a type rating in a turbojet
airplane is sought.
(B) Hold a type rating for a turbopropeller airplane of the same class of
airplane for which the type rating is sought, or have been designated by a
military service as a pilot in command of an airplane of the same class of
airplane for which the type rating is sought, if a type rating in a
turbopropeller airplane is sought.
(C) Have at least 2,000 hours of flight time, of which 500 hours is in
turbine-powered airplanes of the same class of airplane for which the type
rating is sought.
(D) Have at least 500 hours of flight time in the same type airplane as the
airplane for which the rating is sought.
(E) Have at least 1,000 hours of flight time in at least two different
airplanes requiring a type rating.
(5) Subject to the limitation of paragraph (e)(6) of this section, an
applicant who does not meet the requirements of paragraph (e)(4) of this
section may complete all training and testing (except for preflight
inspection) for an additional rating when using a flight simulator if--
(i) The flight simulator is qualified and approved as a Level C or Level
D; and
(ii) The applicant meets at least one of the following:
(A) Holds a type rating in a propeller-driven airplane if a type rating in
a turbojet airplane is sought, or holds a type rating in a turbojet airplane
if a type rating in a propeller-driven airplane is sought; or
(B) Since the beginning of the 12th calendar month before the month in
which the applicant completes the practical test for an additional airplane
rating, has logged:
(1) At least 100 hours of flight time in airplanes of the same class for
which the type rating is sought and which requires a type rating; and
(2) At least 25 hours of flight time in airplanes of the same type for
which the rating is sought.
(6) An applicant meeting only the requirements of paragraph (e)(5) of this
section will be issued an additional rating with a limitation.
(7) The limitation on a certificate issued under the provisions of
paragraph (e)(6) of this section shall state, "This certificate is subject to
pilot-in-command limitations for the additional rating."
(8) An applicant who has been issued a pilot certificate with the
limitation specified in paragraph (e)(7) of this section--
(i) May not act as pilot in command of that airplane for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 15 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in the same type of airplane to which the limitation
applies.
(9) An applicant who does not meet the requirements of paragraph (e)(4) or
paragraph (e)(5) of this section may be issued an additional rating after
successful completion of one of the following requirements:
(i) Compliance with paragraphs (e)(2) and (e)(3) of this section and the
following tasks, which must be successfully completed on a static airplane or
in flight, as appropriate:
(A) Preflight inspection;
(B) Normal takeoff;
(C) Normal ILS approach;
(D) Missed approach; and
(E) Normal landing.
(ii) Compliance with paragraphs (e)(2), (e)(3), and (e)(10) through (e)(12)
of this section.
(10) An applicant meeting only the requirements of paragraph (e)(9)(ii) of
this section will be issued an additional rating with a limitation.
(11) The limitation on a certificate issued under the provisions of
paragraph (e)(10) of this section shall state, "This certificate is subject
to pilot-in-command limitations for the additional rating."
(12) An applicant who has been issued a pilot certificate with the
limitation specified in paragraph (e)(11) of this section--
(i) May not act as pilot in command of that airplane for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 25 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in that airplane of the same type to which the
limitation applies.
(f) Use of a flight simulator or flight training device for an additional
rating in a helicopter. The areas of operation required to be performed by
paragraphs (b), (c), and (d) of this section shall be performed as follows:
(1) Except as provided in paragraph (f)(2) of this section, the areas of
operation must be performed in a helicopter of the same type for the
additional rating sought.
(2) Subject to the limitations of paragraph (f)(3) through (f)(12) of this
section, the areas of operation may be performed in a flight simulator or
flight training device that represents that helicopter for the additional
rating sought.
(3) The use of a flight simulator or flight training device permitted by
paragraph (f)(2) of this section shall be conducted in accordance with an
approved course at a training center certificated under part 142 of this
chapter.
(4) To complete all training and testing (except preflight inspection) for
an additional helicopter rating without limitations when using a flight
simulator--
(i) The flight simulator must be qualified and approved as Level C or
Level D; and
(ii) The applicant must meet at least one of the following if a type rating
is sought in a turbine-powered helicopter:
(A) Hold a type rating in a turbine-powered helicopter or have been
appointed by a military service as a pilot in command of a turbine-powered
helicopter.
(B) Have at least 2,000 hours of flight time that includes at least 500
hours in turbine-powered helicopters.
(C) Have at least 500 hours of flight time in turbine-powered helicopters.
(D) Have at least 1,000 hours of flight time in at least two different
turbine-powered helicopters.
(5) Subject to the limitation of paragraph (f)(6) of this section, an
applicant who does not meet the requirements of paragraph (f)(4) of this
section may complete all training and testing (except for preflight
inspection) for an additional rating when using a flight simulator if--
(i) The flight simulator is qualified and approved as Level C or Level D;
and
(ii) The applicant meets at least one of the following:
(A) Holds a type rating in a turbine-powered helicopter if a type rating in
a turbine-powered helicopter is sought; or
(B) Since the beginning of the 12th calendar month before the month in
which the applicant completes the practical test for an additional helicopter
rating, has logged at least 25 hours of flight time in helicopters of the
same type for which the rating is sought.
(6) An applicant meeting only the requirements of paragraph (f)(5) of this
section will be issued an additional rating with a limitation.
(7) The limitation on a certificate issued under the provisions of
paragraph (f)(6) of this section shall state, "This certificate is subject to
pilot-in-command limitations for the additional rating."
(8) An applicant who is issued a pilot certificate with the limitation
specified in paragraph (f)(7) of this section--
(i) May not act as pilot in command of that helicopter for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 15 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in the same type of helicopter to which the limitation
applies.
(9) An applicant who does not meet the requirements of paragraph (f)(4) or
paragraph (f)(5) of this section may be issued an additional rating after
successful completion of one of the following requirements:
(i) Compliance with paragraphs (f)(2) and (f)(3) of this section and the
following tasks, which must be successfully completed on a static helicopter
or in flight, as appropriate:
(A) Preflight inspection;
(B) Normal takeoff;
(C) Normal ILS approach;
(D) Missed approach; and
(E) Normal landing.
(ii) Compliance with paragraphs (f)(2), (f)(3), and (f)(10) through (f)(12)
of this section.
(10) A applicant meeting only the requirements of paragraph (f)(9)(ii) of
this section will be issued an additional rating with a limitation.
(11) The limitation on a certificate issued under the provisions of
paragraph (f)(10) of this section shall state, "This certificate is subject
to pilot-in-command limitations for the additional rating."
(12) An applicant who has been issued a pilot certificate with the
limitation specified in paragraph (f)(11) of this section--
(i) May not act as pilot in command of that helicopter for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 25 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in that helicopter of the same type as to which the
limitation applies.
(g) Use of a flight simulator or flight training device for an additional
rating in a powered-lift. The areas of operation required to be performed by
paragraphs (b), (c), and (d) of this section shall be performed as follows:
(1) Except as provided in paragraph (g)(2) of this section, the areas of
operation must be performed in a powered-lift of the same type for the
additional rating sought.
(2) Subject to the limitations of paragraphs (g)(3) through (g)(12) of
this section, the areas of operation may be performed in a flight simulator
or flight training device that represents that powered- lift for the
additional rating sought.
(3) The use of a flight simulator or flight training device permitted by
paragraph (g)(2) of this section shall be conducted in accordance with an
approved course at a training center certificated under part 142 of this
chapter.
(4) To complete all training and testing (except preflight inspection) for
an additional powered-lift rating without limitations when using a flight
simulator--
(i) The flight simulator must be qualified and approved as Level C or
Level D; and
(ii) The applicant must meet at least one of the following if a type rating
is sought in a turbine powered-lift:
(A) Hold a type rating in a turbine powered-lift or have been appointed by
a military service as a pilot in command of a turbine powered-lift.
(B) Have at least 2,000 hours of flight time that includes at least 500
hours in turbine powered-lifts.
(C) Have at least 500 hours of flight time in turbine powered-lifts.
(D) Have at least 1,000 hours of flight time in at least two different
turbine powered-lifts.
(5) Subject to the limitation of paragraph (g)(6) of this section, an
applicant who does not meet the requirements of paragraph (g)(4) of this
section may complete all training and testing (except for preflight
inspection) for an additional rating when using a flight simulator if--
(i) The flight simulator is qualified and approved as Level C or Level D;
and
(ii) The applicant meets at least one of the following:
(A) Holds a type rating in a turbine powered-lift if a type rating in a

turbine powered-lift is sought; or
(B) Since the beginning of the 12th calendar month before the month in
which the applicant completes the practical test for an additional powered-
lift rating, has logged at least 25 hours of flight time in powered-lifts of
the same type for which the rating is sought.
(6) An applicant meeting only the requirements of paragraph (g)(5) of this
section will be issued an additional rating with a limitation.
(7) The limitation on a certificate issued under the provisions of
paragraph (g)(6) of this section shall state, "This certificate is subject to
pilot-in-command limitations for the additional rating."
(8) An applicant who is issued a pilot certificate with the limitation
specified in paragraph (g)(7) of this section--
(i) May not act as pilot in command of that powered-lift for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 15 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in the same type of powered-lift to which the
limitation applies.
(9) An applicant who does not meet the requirements of paragraph (g)(4) or
paragraph (g)(5) of this section may be issued an additional rating after
successful completion of one of the following requirements:
(i) Compliance with paragraphs (g)(2) and (g)(3) of this section and the
following tasks, which must be successfully completed on a static powered-
lift or in flight, as appropriate:
(A) Preflight inspection;
(B) Normal takeoff;
(C) Normal ILS approach;
(D) Missed approach; and
(E) Normal landing.
(ii) Compliance with paragraphs (g)(2), (g)(3), and (g)(10) through (g)(12)
of this section.
(10) An applicant meeting only the requirements of paragraph (g)(9)(ii) of
this section will be issued an additional rating with a limitation.
(11) The limitation on a certificate issued under the provisions of
paragraph (g)(10) of this section shall state, "This certificate is subject
to pilot-in-command limitations for the additional rating."
(12) An applicant who has been issued a pilot certificate with the
limitation specified in paragraph (g)(11) of this section--
(i) May not act as pilot in command of that powered-lift for which the
additional rating was obtained under the provisions of this section until the
limitation is removed from the pilot certificate; and
(ii) May have the limitation removed by accomplishing 25 hours of
supervised operating experience as pilot in command under the supervision of
a qualified and current pilot in command, in the seat normally occupied by
the pilot in command, in that powered-lift of the same type as to which the
limitation applies.
(h) Aircraft not capable of instrument maneuvers and procedures. An
applicant for a type rating who provides an aircraft not capable of the
instrument maneuvers and procedures required by the appropriate requirements
contained in Sec. 61.157 of this part for the practical test may--
(1) Obtain a type rating limited to "VFR only"; and
(2) Remove the "VFR only" limitation for each aircraft type in which the
applicant demonstrates compliance with the appropriate instrument
requirements contained in Sec. 61.157 or Sec. 61.73 of this part.
(i) Multiengine, single-pilot station airplane. An applicant for a type
rating in a multiengine, single-pilot station airplane may meet the
requirements of this part in a multiseat version of that multiengine
airplane.
(j) Single-engine, single-pilot station airplane. An applicant for a type
rating in a single-engine, single-pilot station airplane may meet the
requirements of this part in a multiseat version of that single-engine
airplane.
(k) Waivers. Unless the Administrator requires certain or all tasks to be
performed, the examiner who conducts the practical test may waive any of the
tasks for which the Administrator approves waiver authority.
pilot certificates (for parts 121 and 135 use only).

[Amdt. 61-102, 62 FR 19298, Apr. 4, 1997; Amdt. 61-103, 62 FR 40899, July
30, 1997, as amended by Amdt. 61-104, 63 FR 20287, Apr. 23, 1998]