CS 31HB.47 Heater system

ED Decision 2009/005/R

1. The system must be designed and installed so as not to create a fire hazard.
2. Parts adjacent to a heater (and if applicable, its flame) and the occupants must be protected from excessive heat.
3. There must be controls, instruments, or other equipment essential to safe control and operation of the heater system. They must be shown to be able to perform their intended functions during normal and emergency operation.
   1. Where a heater system has more than one fuel supply or more than one control on each fuel supply, there must be unambiguous means to differentiate between each control, its source of supply and its function. (See AMC 31HB.47(c)(1))
   2. The heater system must have a device or other means to indicate the quantity of fuel available. (See AMC 31HB.47(c)(2))
   3. For a burner, each control system must have a device that indicates whether the heat output is high, normal or low. (See AMC 31HB.47(c)(3))
4. The reliability of the heater system must be substantiated by a test designed to reflect the limiting conditions likely to be encountered in service, both in kind and duration.
   1. For a burner, the test must include at least three flameouts and restarts.
   2. Each element of the system must be serviceable at the end of the test.
5. For a burner, the pilot light (or other means of ignition) must be shown to operate reliably in typical gusts and rain, must be readily accessible for relighting and must be easily relit. Continued operation of a heater must be possible in the event of a sustained pilot light failure.
6. Except in single-occupant balloons, the heater system must be designed so that in the event of any single failure, it will retain sufficient heat output to maintain level flight. (See AMC 31HB.47(f))

ED Decision 2009/005/R

Colour coding of controls and fuel feeds is an acceptable means of compliance.

ED Decision 2009/005/R

An indication whether the individual fuel cell is FULL and indication for the use of the last 30% (or more) of the usable amount of fuel is considered compliant with this requirement.

ED Decision 2009/005/R

A device that indicates the fuel pressure before entering each main blast valve is considered compliant with this requirement.

ED Decision 2009/005/R

For those single occupant balloons which do not meet the single failure criteria in the requirement, measures to compensate for the increased likelihood of a cold descent landing (i.e. one without the assistance of a heater system) should be discussed with the Agency.

→ CS 31HB.49