If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Anyone flown atn LPV yet?
John R. Copeland wrote:
"Ron Rosenfeld" wrote in message ... ) Yes, the approaches are a pleasure to fly, but the step change in course width can cause a coupled approach to give a small disturbance, for me. If the needle isn't exactly centered at the point of switching, my autopilot hunts for a few moments, until it stabilizes again. It's a small amount, and not an operational problem, but it makes the GPS approaches slightly less smooth than an ILS, which doesn't have that bump. My autopilot is a Collins AP-107. Who sees any similar effect with other autopilots? Is this a GNS 480 that is giving the step changes? Do you see these small incremental changes on your CDI or HSI? |
#12
|
|||
|
|||
Anyone flown atn LPV yet?
On Sat, 16 Dec 2006 11:52:57 -0500, "John R. Copeland"
wrote: "Ron Rosenfeld" wrote in message ... On Fri, 15 Dec 2006 06:56:17 -0800, Sam Spade wrote: Subject line says it all. If so, what was your impression? Not yet. But I have flown an LNAV with advisory vertical guidance. The needles were extremely stable -- more so than an ILS with my equipment. Pretty easy to fly. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) Yes, the approaches are a pleasure to fly, but the step change in course width can cause a coupled approach to give a small disturbance, for me. If the needle isn't exactly centered at the point of switching, my autopilot hunts for a few moments, until it stabilizes again. It's a small amount, and not an operational problem, but it makes the GPS approaches slightly less smooth than an ILS, which doesn't have that bump. My autopilot is a Collins AP-107. Who sees any similar effect with other autopilots? I've not noted a "step change" in my CNX80. The changes in sensitivity are supposed to be gradual, and at the FAF I believe the "scaling" goes to angular, to mimic an ILS. But maybe I've just missed it. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) |
#13
|
|||
|
|||
Anyone flown atn LPV yet?
Ron Rosenfeld wrote:
I've not noted a "step change" in my CNX80. The changes in sensitivity are supposed to be gradual, and at the FAF I believe the "scaling" goes to angular, to mimic an ILS. But maybe I've just missed it. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) As I understand it, it first ramps down to 0.3 from 1.0 starting at 2 miles from the LPV FAF, then it does a continuous angular "ramp down" from the FAF to the runway so it will be ILS-like close in. Have you noted that doing small incremental "stepping" on an LPV IAP during final approach? |
#14
|
|||
|
|||
Anyone flown atn LPV yet?
"Sam Spade" wrote in message ...
Ron Rosenfeld wrote: I've not noted a "step change" in my CNX80. The changes in sensitivity are supposed to be gradual, and at the FAF I believe the "scaling" goes to angular, to mimic an ILS. But maybe I've just missed it. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) As I understand it, it first ramps down to 0.3 from 1.0 starting at 2 miles from the LPV FAF, then it does a continuous angular "ramp down" from the FAF to the runway so it will be ILS-like close in. Have you noted that doing small incremental "stepping" on an LPV IAP during final approach? You say LPV course widths ramp down gradually over some miles? Should LNAV/VNAV approaches do the same? Around the FAF, it's usually too busy a time to collect every detail. If it's not a step change in course width, it seems at least pretty quick. Quick enough to disturb my autopilot a small amount, it seems. But the reason I asked was to learn if other CNX80 users see a similar effect. So far, the answer seems to be "no". The effect I see is small, though, so it could be ignored easily. If the blame turns out to be on my autopilot, I could send it back to Collins to get it re-calibrated. |
#15
|
|||
|
|||
Anyone flown atn LPV yet?
John R. Copeland wrote:
You say LPV course widths ramp down gradually over some miles? Should LNAV/VNAV approaches do the same? RNAV IAPs, other than LPV, ramp down from 1.0 miles to 0.3 miles starting two miles prior to the FAF, and completed at the FAF. Then, the sensitivity remains at 0.3 throughout the final approach segment. With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. |
#16
|
|||
|
|||
Anyone flown atn LPV yet?
"Sam Spade" wrote in message ...
With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. Thanks. I didn't know of the difference. I'll watch for it. |
#17
|
|||
|
|||
Anyone flown atn LPV yet?
John R. Copeland wrote:
"Sam Spade" wrote in message ... With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. Thanks. I didn't know of the difference. I'll watch for it. I getting up to speed on the 145/146 spec. The LNAV approach also reduces in the lateral mode similar to the laternal mode of the LPV approach. When you reach the MAP, it is only 350 feet full scale deflection, instead of the 0.3 mile defection for TSO 129 LNAV final. |
#18
|
|||
|
|||
Anyone flown atn LPV yet?
"Sam Spade" wrote in message ... John R. Copeland wrote: "Sam Spade" wrote in message ... With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. Thanks. I didn't know of the difference. I'll watch for it. I getting up to speed on the 145/146 spec. The LNAV approach also reduces in the lateral mode similar to the laternal mode of the LPV approach. When you reach the MAP, it is only 350 feet full scale deflection, instead of the 0.3 mile defection for TSO 129 LNAV final. Do you have a link to the TSO handy? And is it the full requirement? Last time I tried to read TSO C129, seems like it was a skeleton document, referencing a commercial spec that had to be purchased. |
#19
|
|||
|
|||
Anyone flown atn LPV yet?
"Sam Spade" wrote in message ...
John R. Copeland wrote: "Sam Spade" wrote in message ... With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. Thanks. I didn't know of the difference. I'll watch for it. I getting up to speed on the 145/146 spec. The LNAV approach also reduces in the lateral mode similar to the laternal mode of the LPV approach. When you reach the MAP, it is only 350 feet full scale deflection, instead of the 0.3 mile defection for TSO 129 LNAV final. I'm definitely gonna have to set up an experiment over that! I'd expect to have noticed it, if my CNX80 behaved that way. Is that a behavior demanded by TSO-C145/146, or merely allowed? |
#20
|
|||
|
|||
Anyone flown atn LPV yet?
Stan Prevost wrote:
"Sam Spade" wrote in message ... John R. Copeland wrote: "Sam Spade" wrote in message ... With LPV, the sensitivity continues to increase (course width decreases) from the FAF to the runway. That causes LPV to be an angular system from the FAF to the runway. Not so with other RNAV. Thanks. I didn't know of the difference. I'll watch for it. I getting up to speed on the 145/146 spec. The LNAV approach also reduces in the lateral mode similar to the laternal mode of the LPV approach. When you reach the MAP, it is only 350 feet full scale deflection, instead of the 0.3 mile defection for TSO 129 LNAV final. Do you have a link to the TSO handy? And is it the full requirement? Last time I tried to read TSO C129, seems like it was a skeleton document, referencing a commercial spec that had to be purchased. Same with 145/146. The nuts-and-boths is in RTCA Doument 229C. $350. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Haven't flown in a long while... | Flyingmonk | Piloting | 33 | April 5th 06 06:30 AM |
Total cross country distance flown | Bill Daniels | Soaring | 9 | November 4th 05 11:53 AM |
If there are any pilots here that have ever flown aerial surveys.... | terrygeosearch | Piloting | 1 | February 8th 05 06:45 PM |
If there are any pilots here that have ever flown aerial surveys.... | terrygeosearch | General Aviation | 0 | February 2nd 05 04:11 AM |
Most aircraft types flown by 1 pilot? | Chad Irby | Military Aviation | 10 | January 7th 04 03:47 AM |