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primary flight instruments on partial panel
In primary and supporting method of attitude instrument flying, which
do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? thank you Greg greggordon.org/flying |
#2
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primary flight instruments on partial panel
You would use the TC or TB to control bank angle, it is the
instrument that you control, therefore primary. You monitor the compass to fly a heading which is the desired result. Using the compass as a control instrument generally requires a south heading so that the compass turning error is in the correct direction. -- James H. Macklin ATP,CFI,A&P "Greg" wrote in message ups.com... | In primary and supporting method of attitude instrument flying, which | do you consider the primary instrument for bank in the partial panel | situation (loss of both attitude indicator and heading indicator)? | Turn coordinator or magnetic compass? | thank you | Greg | greggordon.org/flying | |
#3
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primary flight instruments on partial panel
Greg wrote:
In primary and supporting method of attitude instrument flying, which do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? The magnetic compass isn't worth **** in a turn. It should only be used as a heading reference in straight-and-level flight. If you've got a good ADF you can tune in an AM broadcast station and that makes a dandy DG replacement. Pick a station that's far enough away that azimuth to the station is approximately constant but close enough that you get a good strong signal. Not that most planes have ADFs these days, and the ones that do exist tend to be pretty cruddy. With practice, you can fly a decent ILS with just a TC, ASI, and CDI. No AI, no DG, not even a wet compass. |
#4
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primary flight instruments on partial panel
Roy Smith wrote: Greg wrote: In primary and supporting method of attitude instrument flying, which do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? The magnetic compass isn't worth **** in a turn. It should only be used as a heading reference in straight-and-level flight. Actually compass turns are taught of all instrument pilots. An instrument pilot should be able to tell you what the compass will indicate in a turn and be able to turn to exact headings using just the compass. For most places in the U.S. the correction is +30/-30. See page 5-25 of the FAA's "Instrument Flying Handbook" http://www.faa.gov/library/manuals/a...-8083-15-1.pdf "...For example, when turning from an easterly direction to north, where the latitude is 30°, start the roll-out when the compass reads 37° (30° plus one-half the 15° angle of bank, or whatever amount is appropriate for your rate of roll-out). When turning from an easterly direction to south, start the roll-out when the magnetic compass reads 203° (180° plus 30° minus one-half the angle of bank). When making similar turns from a westerly direction, the appropriate points at which to begin your roll-out would be 323° for a turn to north, and 157° for a turn to south...." -Robert, CFII |
#5
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primary flight instruments on partial panel
If I had my druthers, compass turns would be eliminated from training and
timed turns used instead. The PTS does not require compass turns, but most CFII's teach them anyway. I'll bet my life on a timed turn, but not on a compass turn. Whenever this question arises I postulate this scenario: It is a dark and stormy night, ice is beginning to become apparent, the wife's knuckles are white and the kids are crying. The heading indicator craps out and the mag compass looks like a washing machine. What a fine time to be determining leads and lags and remembering rules. Bob Gardner "Robert M. Gary" wrote in message ups.com... Roy Smith wrote: Greg wrote: In primary and supporting method of attitude instrument flying, which do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? The magnetic compass isn't worth **** in a turn. It should only be used as a heading reference in straight-and-level flight. Actually compass turns are taught of all instrument pilots. An instrument pilot should be able to tell you what the compass will indicate in a turn and be able to turn to exact headings using just the compass. For most places in the U.S. the correction is +30/-30. See page 5-25 of the FAA's "Instrument Flying Handbook" http://www.faa.gov/library/manuals/a...-8083-15-1.pdf "...For example, when turning from an easterly direction to north, where the latitude is 30°, start the roll-out when the compass reads 37° (30° plus one-half the 15° angle of bank, or whatever amount is appropriate for your rate of roll-out). When turning from an easterly direction to south, start the roll-out when the magnetic compass reads 203° (180° plus 30° minus one-half the angle of bank). When making similar turns from a westerly direction, the appropriate points at which to begin your roll-out would be 323° for a turn to north, and 157° for a turn to south...." -Robert, CFII |
#6
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primary flight instruments on partial panel
Bob Gardner wrote: If I had my druthers, compass turns would be eliminated from training and timed turns used instead. The PTS does not require compass turns, but most CFII's teach them anyway. I'll bet my life on a timed turn, but not on a compass turn. Funny, I think compass turns are much easier under stressful situations. Having to start and stop the clock and compute the time necessary for the turn while holding an exact standard rate turn would be hard. Of course, in most situations, turning within 1degree is not required. -Robert |
#7
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primary flight instruments on partial panel
Funny, I think compass turns are much easier under stressful
situations. Having to start and stop the clock I disagree. A quick calculation tells me where the second hand should be when I'm done. I roll out, then make little corrections as needed. Jose -- The monkey turns the crank and thinks he's making the music. for Email, make the obvious change in the address. |
#8
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primary flight instruments on partial panel
I don't like purely timed turns because I rarely get them to work accurately. It takes time to bank into the turn and bank out and any inaccuracies in holding a standard rate turn you can be off by 20 or 30 degrees. Using compass turns, even if don't compensate for banking errors you will only be off by 30 degrees. What I teach is to make large turns using the compass turns (with or without banking errors), and then make fine adjustments. In a sense this is a combination of compass turns and timed turns, except you don't start and stop a clock. You time the fine adjustments in your head. Bob Gardner wrote: If I had my druthers, compass turns would be eliminated from training and timed turns used instead. The PTS does not require compass turns, but most CFII's teach them anyway. I'll bet my life on a timed turn, but not on a compass turn. Whenever this question arises I postulate this scenario: It is a dark and stormy night, ice is beginning to become apparent, the wife's knuckles are white and the kids are crying. The heading indicator craps out and the mag compass looks like a washing machine. What a fine time to be determining leads and lags and remembering rules. Bob Gardner "Robert M. Gary" wrote in message ups.com... Roy Smith wrote: Greg wrote: In primary and supporting method of attitude instrument flying, which do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? The magnetic compass isn't worth **** in a turn. It should only be used as a heading reference in straight-and-level flight. Actually compass turns are taught of all instrument pilots. An instrument pilot should be able to tell you what the compass will indicate in a turn and be able to turn to exact headings using just the compass. For most places in the U.S. the correction is +30/-30. See page 5-25 of the FAA's "Instrument Flying Handbook" http://www.faa.gov/library/manuals/a...-8083-15-1.pdf "...For example, when turning from an easterly direction to north, where the latitude is 30°, start the roll-out when the compass reads 37° (30° plus one-half the 15° angle of bank, or whatever amount is appropriate for your rate of roll-out). When turning from an easterly direction to south, start the roll-out when the magnetic compass reads 203° (180° plus 30° minus one-half the angle of bank). When making similar turns from a westerly direction, the appropriate points at which to begin your roll-out would be 323° for a turn to north, and 157° for a turn to south...." -Robert, CFII |
#9
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primary flight instruments on partial panel
Years ago a FSDO/GADO Inspector pulled that one on me on a instrument flight
check. Al " If you've got a good ADF you can tune in an AM broadcast station and that makes a dandy DG replacement. Pick a station that's far enough away that azimuth to the station is approximately constant but close enough that you get a good strong signal. Not that most planes have ADFs these days, and the ones that do exist tend to be pretty cruddy. |
#10
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primary flight instruments on partial panel
"Greg" wrote in message
ups.com... In primary and supporting method of attitude instrument flying, which do you consider the primary instrument for bank in the partial panel situation (loss of both attitude indicator and heading indicator)? Turn coordinator or magnetic compass? The turn co-ordinator is your primary measure of bank, for a couple of reasons. First, the compass doesn't measure bank angle - it just shows what direction you're pointing in - whereas the TC does show the degree to which you're banked. Second, and most importantly, because of the way it's put together, the compass doesn't turn steadily, and so it'd be wrong to fool yourself into thinking that the faster the compass was moving, the more you're banked. Have a go one day and you'll see. Take someone competent with you to look out of the window, get to a safe place and height, make sure your DI's set correctly, and do a rate-one turn through 720 degrees or more (go around as much as you like, in fact). In the northern hemisphere at least, you'll note that when the DI goes through 090 or 270, the compass stands a fair chance of agreeing with the DI. As you go through north, though, the compass will under-read, and as you go through south, it'll over-read. The only time you can rely on the compass is when going in a straight line - which is why you always check and adjust your DI when flying in a straight line. Hence if you want to do a partial-panel turn in IMC, you fly straight and check the compass, then do a rate-one turn (the turn co-ordinator shows you the bank angle) for the required number of seconds - three degrees per second for a rate-one turn, of course. You then level out, give the compass a few seconds to stop wiggling, and then adjust your heading if you're a little bit out. I seem to recall in the IMC rating test you have to get to within five or ten degrees of the desired heading with one initial turn and one "fine tune" adjustment - which is generally pretty achievable. David C |
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