prob not the one you're thinking of but,

BOG....


ALPA Superior Airmanship Award
Late on the evening of April 13, 2004, United Flight 854,
Boeing 767-300 service from Buenos Aires, Argentina, to
Miami, Fla., was in cruise flight at FL310 over the jungles
of southern Colombia, South America. Capt. Brian Witcher
and First Officers Donald Arlotta and Ross Windom were
the flight crew that night.
Capt. Witcher later recalled the flight, up until that
moment, as “a normal all-nighter and the last leg of a fiveday
trip. With Don, the relief pilot, flying, I was moments
away from my rest period.”
Suddenly, the autopilot warning horn went off, the cockpit
went bright with standby lighting, and the first officer’s
panel went blank. In a proficiency checkride, Capt.
Witcher had seen a demonstration of what this problem
appeared to be—a complete loss of A/C power, with the
hydraulic motor generator (HMG) activating to supply
power to the captain’s instruments.
Capt. Witcher took manual control of the airplane and
called for a checklist to deal with the electrical failure.
The B-767 was fast approaching the terrain-critical area
south of Bogota, Colombia, and Capt. Witcher thought
about diverting to Caracas, Venezuela, to avoid the Andes
Mountains lurking below in the darkness. Then the pilots
realized that their “simple” electrical problem was
something else.
The overhead electrical panel appeared normal, with
no lights on except for the battery discharge light. In fact,
the entire overhead panel was normal, with only the autospeedbrake
and rudder ratio lights illuminated. The pilots
pressed the light-test switch and confirmed that all
the lights worked and none of the bulbs were burned out.
F/O Windom arrived from the crew rest area. The three
pilots discussed the situation and their options. Shortly
afterward, Capt. Witcher’s instruments began to fail.
The pilots immediately declared an emergency and
asked air traffic control for a clearance to Bogota. They
tried to establish radio communications with United’s
dispatch office, both through HF and satellite radios, without
success.
The EICAS displays were full of cautions. The pilots
soon realized that no checklist existed to cover the situation
in which they found themselves. They knew they
had a serious electrical problem, but the HMG should kick
in and keep the captain’s instruments powered—at least,
that’s what the book says.
The only radio still working gave up the ghost while
the pilots were trying to get vectors from Bogota Center.
So much for the book!
Capt. Witcher said later, “While I sat there watching
my instruments die, I decided to try something, anything,
to get some power back. The alternative was a totally black
cockpit in about 15 minutes or so and a night landing at
Bogota, an airport surrounded by very tall mountains,
with all of our electronic navigation and communication
equipment useless.”
Capt. Witcher reset the generator control circuit breakers.
The pilots were surprised when the VHF radio, and
Capt. Witcher’s instruments, came to life again.
“No problem now,” they thought. “We still have an
emergency, but with some electrical power.”
Their elation was short-lived: the VHF radio quit again,
and Capt. Witcher’s instruments began to fail, while the
airplane was still about 200 nautical miles from Bogota.
The FAA requires manufacturers to demonstrate that a
modern airliner can continue to operate safely for 30 minutes
with no electrical power except the juice in the battery.
That’s with a new battery, and after the 30 minutes
has gone by, it’s anybody’s guess how much longer the
battery will provide essential power.
The pilots of Flight 854 squeezed 41 minutes from their
30-minute battery because they turned off everything they
could, including the outside lights, to conserve battery
power.
The pilots were very relieved when the landing gear
lowered when commanded, because unlocking the gear
requires some electrical power. Capt. Witcher reset the
generator control circuit breaker three times before they
landed safely, but with no clearance from Bogota Tower,
because their radios still didn’t work. The pilots landed
with less than two volts of battery power left.
The airplane was certified for extended twin-engine
operations and has redundant electrical generating systems
to prevent total loss of both A/C and D/C power.
The pilots would not learn until after the flight that a single
bracket grounds both transformer rectifier units in the A/
C electrical system. United’s Maintenance Department
eventually found that corrosion had caused a short circuit
of the grounding bracket and that the HMG did not
come on line because it falsely sensed that the airplane
had normal A/C power.