DEPARTMENT OF CIVIL AVIATION
Airworthiness Notices
T/16
ELECTRICAL GENERATION SYSTEMS – SINGLE-ENGINED AIRCRAFT
1. Applicability
1.1. Investigations into accidents and incidents involving loss of electrical power on
single-engined aircraft have shown that the standards for warning of failures of
generated power have not kept pace with such system developments and
inadequacies are all too often apparent.
1.2. The purpose of this Notice is to publish a requirement that clear and unmistakable
warning of the loss of generated electrical power (to the main bus-bar) aircraft as
detailed in paragraph 2.1.1, by the introduction, where necessary, of retrospective
modifications.
2. Requirements
2.1. For all single-engined aircraft fitted with systems or equipment as defined in
paragraph 2.1.1 of this Notice, compliance with paragraphs 2.2 and 2.3, or with a
DCA approved alternative providing an equivalent level of airworthiness, is
required.
2.1.1. Compliance with this Notice will be required on single-engined aircraft
equipped with electrically-operated systems or equipment the loss of which
could prejudice continued safe flight and landing. Such systems or equipment
include:
(a) electrically-powered mandatory flight instruments where no acceptable
alternatives are provided;
(b) electronic ignition;
(c) electrically-operated landing gear;
(d) a minimum radio fit;
(e) any other system which could prejudice continued safe flight and landing.
2.2. A clear and unmistakable red visual warning shall be provided, within the pilot’s
normal scan of vision, to give indication of the reduction of the voltage at the aircraft
bus-bar to a level where the battery commences to support all or part of the electrical
load of the aircraft.
2.3. Guidance shall be given in the appropriate aircraft manual(s) on any actions to be
taken by the pilot should the warning operate. See also paragraph 3.2.
10th June 2015 Page 1 of 2 Issue 01
DEPARTMENT OF CIVIL AVIATION
Airworthiness Notices
T/16
3. Additional information
3.1. The recommended voltage levels for operating the warning required under paragraph
2.2 of this Notice are 25 volts to 25.5 volts for a nominal 24 volt dc system and 12.5
volts to 13 volts for a nominal 12 volt dc system.
3.2. The battery duration should be sufficient to make a safe landing and should not be
less than 30 minutes, subject to the prompt completion of any drills. This duration
need only be a reasonable estimate and not necessarily calculated by a detailed
electrical load analysis. However, when making this estimate, only 75% of the
battery name plate capacity should be considered as available because of loss of
battery efficiency during service.
3.3. Guidance information for achieving compliance with this notice can be seen CAAIP
Leaflet 24-50. Owners and operators are recommended to contact the aircraft
constructor or main agent for information regarding suitable means of compliance
with this Notice.
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