BOB O’QUINN
BETTER PILOT / SAFETY WIRE
When the Lights Go Out
How to handle electrical system failures
THERE’S AN OLD ADAGE that flying is 99 percent boredom and 1 percent sheer terror. A great deal of flight training is learning what to do
if we find ourselves in that 1 percent dealing with an emergency. One
area in which pilots could improve their training is what to do in an
electrical failure.
From January 1999 to April 2010 electrical failure was listed as a
cause of 109 GA aircraft accidents in the United States, according to
NTSB data. In 54 percent of those reports, the pilots’ response actually worsened the situation.
One example was the 100-hour student pilot who failed to identify the Cessna 152’s electrical system failure when the radio became
inoperative. Then noticing the fuel gauges showed empty, despite
topping off the tanks at her last departure point, she elected to make
a precautionary landing at a nearby airport. Misjudging her
approach and losing control, she landed in a cornfield, nose wheel
first, collapsing the nose wheel.
Pilot error rates increase significantly when a complex aircraft
experiences an electrical system failure. A typical example was the
Cessna 210 pilot who decided to execute a precautionary landing
after confirming a complete electrical failure. After only the nose
gear lowered, he attempted to lower the mains, using the alternative
extension system, but he failed to follow the pilot’s operating handbook (POH) procedures and landed with the mains retracted.
Accident Causes Following Electrical System Failure
Electrical System
68%
PIC Error
54%
Landing Gear Failure
71%*
Inadequate Maintenance
18%
Mechanical Failure
6.3%
Inadequate Manufacturer’s
Design (experimental)
5.5%
Known Deficiency—PIC
3.7%
* Of 109 accident aircraft, 55 had retractable gear and 71 percent of those had a gear failure.
Percentages add up to more than 100 because of multiple causes.
Source: 109 NTSB Electrical System Failure Accident Reports, Jan. 1, 1999, to Apr. 25, 2010
As student pilots, we learn that an electrical system failure in a non-complex aircraft is
serious enough to land at an airport as soon as
practical and have it repaired before continuing the flight. Because a total electrical
system failure will render all electrically
operated instruments and systems inoperative, pilots will need to plan their approach
and landing accordingly—a good reason to
stay current landing with no flaps or trim (if
electric). If the electrical system fails at night,
a significantly higher knowledge and skill
level are required to navigate the aircraft to a
lighted airport and land safely without benefit of instrument lights or landing lights.
When complex aircraft experience a total
electrical failure, the pilot is unable to operate boost pumps or transfer fuel, engage the
autopilot, or operate electrical flaps or trim.
Also, he or she will have to lower the landing
gear manually without any lighted indication of the landing gear’s position. Of the 109
accident aircraft, 55 had retractable landing
gear and 71 percent of those sustained landing gear failure, mostly because the pilot
failed to follow POH procedures for emergency gear extension.
Although nearly 20 percent of the accidents were attributed to inadequate
maintenance, electrical failures can occur
any time. Prevention begins with a good preflight, checking for any tripped circuit
breakers. If one is tripped, push it in and
turn on the electrical power. If it pops again,
the cause should be investigated and a repair
made before flight.
The potential for an electrical failure
turning into a disaster can be reduced by
reviewing the POH to understand the aircraft’s electrical system and emergency
procedures. This familiarization will increase
the likelihood of the pilot making good decisions promptly in the event of a partial or
total electrical system failure.
Robert O’Quinn, EAA 742434, is a certificated flight
instructor and advanced ground instructor whose primary
aviation focus is on tailwheel training.
