14 CFR §61.115

1. (a)If a person who applies for a private pilot certificate with a balloon rating takes a practical test in a balloon with an airborne heater:
   1. (1)The pilot certificate will contain a limitation restricting the exercise of the privileges of that certificate to a balloon with an airborne heater; and
   2. (2)The limitation may be removed when the person obtains the required aeronautical experience in a gas balloon and receives a logbook endorsement from an authorized instructor who attests to the person's accomplishment of the required aeronautical experience and ability to satisfactorily operate a gas balloon.
2. (b)If a person who applies for a private pilot certificate with a balloon rating takes a practical test in a gas balloon:
   1. (1)The pilot certificate will contain a limitation restricting the exercise of the privilege of that certificate to a gas balloon; and
   2. (2)The limitation may be removed when the person obtains the required aeronautical experience in a balloon with an airborne heater and receives a logbook endorsement from an authorized instructor who attests to the person's accomplishment of the required aeronautical experience and ability to satisfactorily operate a balloon with an airborne heater.