MOONEY
M20TN - MODEL TYPE-S
SECTION VII
AIRPLANE AND SYSTEM DESCRIPTION
7 -- 27
AIRPLANE FLIGHT MANUAL
ORIGINAL ISSUE -- 04-02-2008
connected to the aircraft electrical system at the main bus. In the event of an alternator failure, a
20 Amp standby alternator, actuated by the pilot using a manual switch in the cockpit labeled
EMER BUS, powers Essential systems as presented on the fascia of the Circuit Breaker Panel. If
the Primary and Standby charging systems fail, the ship’s battery(s) provide the system with
electrical power.
The M20TN has 2 separate 11 ampere/hour batteries, which are mounted in the tail cone. Either
battery can be selected to power the electrical bus using the BATT 1/BATT 2 select rocker switch
mounted on the LH side of the Pilot’s Flight Panel. Only one battery will power the bus at any one
time. The unselected battery will be trickle charged by the ship’s alternator when the engine is
running and the ammeter shows a positive charge condition. The selected battery is connected
to the aircraft bus by the BATT MASTER rocker switch located on the LH side of the Pilot’s Flight
Panel. The aircraft has an External Power receptacle located on the left side of the tailcone, aft of
the tailcone access panel. When external power is connected to this receptacle, either or both
batteries may be charged. The External Power receptacle can also be used for maintenance
activities, or to start the engine.
In the event of an alternator failure, selecting EMER BUS will:
S
Power the standby alternator.
S
Shed unessential loads and power Essential systems consisting of:
S
G1000 system, which is comprised of the PFD/MFD, AHRS, ADC, Com1, Nav1, GPS1,
transponder, audio panel, and Engine Instruments;
S
An independent, standby attitude indicator (artificial horizon);
S
Aux. Overhead Equipment, Aux Panel Equipment, and Ice Protection
Activating the EMER BUS switch bypasses the master switch and electrically feeds the standby
attitude indicator and all standby lighting using both main batteries in the event that the Standby
Alternator also fails.
NOTE:
In flight, NEVER deselect the BATT MASTER switch unless the EMER BUS switch
is energized.
ESSENTIAL BUS
The Essential bus is tied directly to the main aircraft battery via the non--essential bus. When the
master switch is turned on, power is immediately supplied to the Essential and non--Essential
busses. The Essential bus provides power to the G1000 equipment and to the backup instru-
ments. When the Emergency Bus switch is activated by the pilot, the standby alternator is
brought online and two relays close to power the essential bus via a secondary path. The se-
lected main battery (two main batteries are available) remains online.
NON - ESSENTIAL BUS
The non--essential bus powers the autopilot, turn coordinator required for the autopilot, the
Stormscope, and GIA #2. This bus is load shed manually by the pilot by pulling the BATT circuit
breaker when the standby alternator and emergency bus switch are activated.
EQUIPMENT LOCATION
The G1000 ADC and GEA LRU’s are located behind the PFD and MFD, which may be removed
using a hexagonal tool. The magnetometer is located in the right wing outboard of the landing
light. The AHRS, and remaining LRU’s are located in the forward section of the tailcone near the
main batteries.
