LongHauler From Canada, joined Mar 2004, 4935 posts, RR: 43
Reply 2, posted (9 years 4 months 1 week 5 days 21 hours ago) and read 1413 times:
If I recall, the RMIs would have the fluxgate compass as their source. The compasses in the cockpit, ie the "whiskey" compasses are a backup.
The old fluxgate compass, with the sensing needle are 3 from the left on the top of the captain's panel. And, another one, 3 from the right on the top of the F/Os panel. Curiously, they are almost 180 degrees apart, one indicating approx 300, the other 150 degrees!
The manual backup compass, is probably above the top of the panel, out of the range of the picture, to keep it clear of interference from the instruments.
You probably know this, but Robert Serling, included a lot of information about Ivon Spong, and that crash is his book, "The Probable Cause". Suspicion about the fluxgate compass system was one of the possible causes of the crash.
Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
Not being a pilot myself, yet trying to understand the complexities of instrument operation, I was trying to further my limited cockpit knowledge with a better picture of the location of the various instruments.
"The Probable Cause" is an excellent book, and the place I first heard this crash many years ago. His other books, both non-fiction and fiction, are excellent reads, as well.
Tom at MSY
"The criminal ineptitude makes you furious"-Bruce Springsteen, after seeing firsthand the damage from Hurricane Katrina
411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 4, posted (9 years 4 months 1 week 4 days 21 hours ago) and read 1382 times:
A very similar DC-6 accident, with the compass system as the probable cause, occured on the east coast.
Early Sperry remote compass systems utilized three phase AC current for operation (provided by an inverter...IE: a DC motor driving an AC generator, not a static inverter) and every once in awhile, one of the phases would fail, providing an erroneous compass reading.
While flying the DC-6B, I experienced three such failures, and in each case, the compass (RMI) indicated a 120 degree bearing error.