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#21
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Richard Kaplan wrote:
A vacuum faliure with a gradual spooldown of the AI and DG at vary rates is a subtle process, very different from having an instructor suddenly cover up a gyro. You are correct that there is enough redundancy in a typical GA plane to FLY partial panel; the problem is that there is not enough information for most pilots to IDENTIFY a partial panel situation before the situation has become critical. Richard, There seem to be a number of instances where the pilot was aware of the problem -- had described it to ATC and possibly requested some form of assistance -- had been flying the plane for some time more or less under control, and then lost it. So the pilot did identify a partial panel situation before it became critical, he simply couldn't FLY partial panel. The accident Julian posted the link for more-or-less seems to fall into this case, as did a couple of local accidents. Cheers, Sydney |
#22
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"Sydney Hoeltzli" wrote in message ... There seem to be a number of instances where the pilot was aware of the problem -- had described it to ATC and possibly requested some form of assistance -- had been flying the plane for some time No doubt there will always be crashes we cannot avoid. I am sure there are people with tip tanks who run out of fuel; that does not mean tip tanks fail to increase an airplane's range. The fact is that any sim instructor will tell you many pilots have a difficult time identifying gradual loss of the vacuum system and that redundant gyro equipment helps to identify this failure earlier. -- Richard Kaplan, CFII www.flyimc.com |
#23
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On 13-Jul-2003, "Richard Kaplan" wrote: I think that is a really worrisome location. I just flew last month with a very experienced instrument student who had a similar arrangement in his 182RG and developed vertigo and nausea while flying partial panel with his primary AI covered up Our electric AI isn't THAT far to the right. Actually, it's mounted in the right-hand radio stack, right above the DME. (Arrows and other Cherokees from the late 1960s on have a double radio stack. With modern avionics typically taking up less space, there is often room left over. It is a simple matter to fashion a "blank" with a 3" instrument hole to fit in this space, and that places the backup AI within reasonable scan distance for the pilot.) -Elliott Drucker |
#24
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"Sydney Hoeltzli" wrote in message ... | C J Campbell wrote: | Newer vacuum AIs have warning flags, dual vacuum pumps, and vacuum warning | lights on the annunciator panel. If I had an electric AI and a vacuum AI and | they disagreed markedly, I would be suspicious of the one having warning | lights and flags all over it. | | CJ, | | How do newer vacuum AIs come with dual vacuum pumps? | They come with a new airplane attached to them. Not unlike the $350,000 Cessna ball cap I bought. |
#25
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Sydney Hoeltzli writes:
We have a "warning flag" on our newer AI. I note that it is really a low vacuum flag. It doesn't say a thing about how reliably the instrument itself is operating. Yup, I had one freeze but the vacuum was fine so it didn't complain. --kyler |
#26
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Big John wrote:
Sidney - just think out of the box Take AI out of panel leaving hooked up. With power (air/electric) applied rotate the instrument through all attitudes and see if it tumbles and where. If it does not meet specs go get your money back. I don't know, Big John. I still want my turn coordinator left in my primary scan area. Call me old-fashioned, call me a stick in the mud, don't call me too late for dinner. Here's a link to the original post: http://makeashorterlink.com/?Z27312245 The part about the Safety Board conclusion that an R/C plane was involved is at the bottom of the post. But the whole post IMO is very well worth reading. I fly R/C and doubt if any collision took place. Never heard of it in AMA magazine and something like that would be a high profile story for risk of lives and insurance problems. FWIW, this didn't happen in the US. Australia I think. Whether or not it was an R/C plane is really a moot point. It could have easily been a large bird (no feathers or blood though). IIRC an R/C guy in the vicinity of the collision admitted he lost contact w/ his plane when it flew into cloud. The point is, one minute the guy was flying along VMC over a layer, next minute WHUMP! pilot window and right rear window blown out, pilot's headset thrown into baggage, plane flipped inverted and dropped into IMC. Vacuum gyros tumbled, pitot-static instruments unreliable. Pilot saved his butt using T/C, tach, and stall warning. So I'm not exiling my T/C or tach to Siberia on the right side of my panel to make way for an electric horizon which might or might not save my soup partial panel, accident record seems mixed on this point (see for example King Air and Bandierante accident described earlier in thread) IMO both the T/C and the tach have proven value, both in daily flying, partial panel, and in plausible emergencies. I want 'em where I can see 'em, right in the primary scan. Cheers, Sydney |
#27
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On 14-Jul-2003, "Richard Kaplan" wrote: Our electric AI isn't THAT far to the right. Actually, it's mounted in the right-hand radio stack, right above the DME. (Arrows and other Cherokees from the late 1960s on have a double radio stack. With modern avionics OK, that sounds fine... in fact perhaps a good location for others searching for a location for an electric AI. Yes, it works for us. Also, it should be an easy and relatively inexpensive installation (unlike swapping instruments with resultant requirements for changes in wiring harnesses). In our plane, this installation also allowed plenty of space to install an ON/OFF switch next to the electric AI. We leave it off when flying in solid VFR conditions, with the understanding that this will extend its life. So far, so good. It's required no maintenance in over 7 yrs/1400 hrs (knock on wood). -Elliott Drucker |
#28
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On 14-Jul-2003, Roy Smith wrote: Not really. When I'm doing partial panel work, I find I miss the DG much more than I miss the AI. A yoke-mounted GPS in either HSI or moving map mode is a good substitute for a failed DG. Strictly for "situational awareness" of course! You have to be careful in that the update of the GPS display is not instantaneous like the DG's response to heading changes, so it's easy to find yourself "chasing the needle". That's where the backup AI comes in. |
#29
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Why do you think leaving it off most of the time will extend its life?
wrote in message ... ... We leave [our electric AI] off when flying in solid VFR conditions, with the understanding that this will extend its life. So far, so good. It's required no maintenance in over 7 yrs/1400 hrs (knock on wood). -Elliott Drucker |
#30
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I thought that gyro bearings were very susceptible to damage if subjected to
mechanical shock while not turning. If that is true, then turning it off in flight may actually reduce the service life. wrote: In our plane, this installation also allowed plenty of space to install an ON/OFF switch next to the electric AI. We leave it off when flying in solid VFR conditions, with the understanding that this will extend its life. So far, so good. It's required no maintenance in over 7 yrs/1400 hrs (knock on wood). -Elliott Drucker -- --Ray Andraka, P.E. President, the Andraka Consulting Group, Inc. 401/884-7930 Fax 401/884-7950 http://www.andraka.com "They that give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, 1759 |
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