AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Winds on approach Goto page 1, 2, 3  Next          AirTalk.org Forum Index -> Instrument Flight Rules View previous topic :: View next topic   Author Message kevmor Guest Posted: Fri Mar 30, 2007 12:59 am    Post subject: Winds on approach I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? Back to top Mark Hansen Guest Posted: Fri Mar 30, 2007 1:16 am    Post subject: Re: Winds on approach On 03/29/07 12:59, kevmor wrote: Quote: I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? I was taught that you should use the proper power settings during the approach. I would not change these due to my expectation of ground speed. However, with a higher than standard ground speed, you will have to adjust your descent rate to maintain the proper glide path. Here's a question for you to think about. If you have a tail wind which results in a ground speed of 95 knots, do you need to use the category 'B' approach minimums? -- Mark Hansen, PP-ASEL, Instrument Airplane Cal Aggie Flying Farmers Sacramento, CA Back to top Brad Guest Posted: Fri Mar 30, 2007 1:27 am    Post subject: Re: Winds on approach On Mar 29, 3:59 pm, "kevmor" <kev...@gmail.com> wrote: Quote: I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. Why does ground speed matter? Why does the 500fpm matter? Quote: This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. I agree. Quote: What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? What's wrong with a much lower descent rate? All that matters is that you keep your needles centered. Did you have faster traffic behind you and you increased speed as a courtesy? I presume you wanted to maintain 90 kts so that you could time the approach, but aside from it being an ILS where it doesn't matter, your GPS could tell you where to go missed if your glide slope goes TU. Back to top Tim Guest Posted: Fri Mar 30, 2007 1:33 am    Post subject: Re: Winds on approach It's probably a good idea to know the power settings for some high speed descent/approach. Like if you are asked to do maximum speed on approach or something like that. As long as you can handle it and can get the time right then no problem. kevmor wrote: Quote: I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? Back to top Jose Guest Posted: Fri Mar 30, 2007 1:33 am    Post subject: Re: Winds on approach Quote: What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? Exactly. Airspeed is what's crucial for aircraft control. Ground speed is just used for timing. Adjust the timing. If it's gusty, you might want a slightly higher airspeed, just like for VFR landings in gusty winds. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top Bob Gardner Guest Posted: Fri Mar 30, 2007 2:34 am    Post subject: Re: Winds on approach You are timing your ILS approaches? Any reason for this? I can't find anything in my 172P book that suggests 90 kts as an approach speed, even in gusty winds. Seems fast to me. Bob Gardner "kevmor" <kevmor (AT) gmail (DOT) com> wrote in message news:1175198395.920095.85110 (AT) n59g2000hsh (DOT) googlegroups.com... Quote: I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? Back to top Jose Guest Posted: Fri Mar 30, 2007 2:45 am    Post subject: Re: Winds on approach Quote: You are timing your ILS approaches? Any reason for this? I can't find anything in my 172P book that suggests 90 kts as an approach speed, even in gusty winds. Seems fast to me. IF one times their ILS, and loses the glideslope, one can often convert to a localizer approach easily. And approach plates give canned timings for various speeds, 90 knots is probably the best of the bunch for a 172. Of course that's ground speed, not airspeed. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top Mark Hansen Guest Posted: Fri Mar 30, 2007 2:47 am    Post subject: Re: Winds on approach On 03/29/07 14:34, Bob Gardner wrote: Quote: You are timing your ILS approaches? Any reason for this? I can't find anything in my 172P book that suggests 90 kts as an approach speed, even in gusty winds. Seems fast to me. Well ... 90 knots was the speed I was taught to use when flying precision and non-precision approaches (in the C-172 airplane in which I trained). Quote: Bob Gardner "kevmor" <kevmor (AT) gmail (DOT) com> wrote in message news:1175198395.920095.85110 (AT) n59g2000hsh (DOT) googlegroups.com... I flew yesterday and did some practice approaches, and the winds were about 20 knots gusting to 26-28. I've flown almost all approaches so far in a different 172 that had a 180hp conversion. Because of the winds, I kept almost full cruising power on the descents to try and maintain my normal 90 kts ground speed for timing and roughly 500fpm for the ILS. This plane did have an IFR GPS indicating ground speed, but the one I've been using for all other approaches didn't, neither DME. The CFI informed me I should have used known power settings. What are your thoughts? I'm not sure how I would've known the right power setting, unless I used what I normally do, and accept the lower ground speed, then adjust my descent for the ILS to a much lower fpm descent? -- Mark Hansen, PP-ASEL, Instrument Airplane Cal Aggie Flying Farmers Sacramento, CA Back to top Bob Gardner Guest Posted: Fri Mar 30, 2007 2:52 am    Post subject: Re: Winds on approach Conventional wisdom (as I see it) is to execute a miss if you lose the glideslope, go around, prepare and brief the localizer approach, then do it. Changing horses in midstream is not wise policy, especially in the clouds and close to the ground. YMMV, but I'll never teach or advocate the switch. Bob Gardner "Jose" <teacherjh (AT) aol (DOT) nospam.com> wrote in message news:wrWOh.1128$5e2.823 (AT) newssvr11 (DOT) news.prodigy.net... Quote: You are timing your ILS approaches? Any reason for this? I can't find anything in my 172P book that suggests 90 kts as an approach speed, even in gusty winds. Seems fast to me. IF one times their ILS, and loses the glideslope, one can often convert to a localizer approach easily. And approach plates give canned timings for various speeds, 90 knots is probably the best of the bunch for a 172. Of course that's ground speed, not airspeed. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top kevmor Guest Posted: Fri Mar 30, 2007 3:20 am    Post subject: Re: Winds on approach I think I should clarify a couple things from the original post, it was a headwind on the approach, and I also did a VOR, LOC, and GPS. If I used the normal power settings, then on the ILS I could just reduce my descent rate. After reading what you guys said, this should be fine unless I'm told to fly it faster. But either way, on the ILS if the needles are centered, you're good. On the others though, if I kept power at the normal settings with the headwind, I would've descended to the MDA further out... to me this seems like an added risk... For timing these, if I didn't have an IFR GPS or DME (they're new to me), how should I figure the ground speed for timing? On Mar 29, 1:16 pm, Mark Hansen <m...@NOSPAMwinfirst.com> wrote: Quote: I was taught that you should use the proper power settings during the approach. I would not change these due to my expectation of ground speed. However, with a higher than standard ground speed, you will have to adjust your descent rate to maintain the proper glide path. Here's a question for you to think about. If you have a tail wind which results in a ground speed of 95 knots, do you need to use the category 'B' approach minimums? Back to top Jose Guest Posted: Fri Mar 30, 2007 3:25 am    Post subject: Re: Winds on approach Quote: Conventional wisdom (as I see it) is to execute a miss if you lose the glideslope, go around, prepare and brief the localizer approach, then do it. That might be smart for some approaches, but if the only change between an ILS and a localizer is the minima and the timing, being in the habit of timing the ILS will save your bacon if you are low on fuel, racing a storm, or otherwise in a tight spot when the GS goes TU. IT also keeps you in the habit of timing other approaches, especially if you don't fly many. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top Jose Guest Posted: Fri Mar 30, 2007 3:27 am    Post subject: Re: Winds on approach Quote: On the others though, if I kept power at the normal settings with the headwind, I would've descended to the MDA further out... to me this seems like an added risk... For timing these, if I didn't have an IFR GPS or DME (they're new to me), how should I figure the ground speed for timing? As long as you are above the minima, and past any stepdown fixes, you're ok. (This is one reason localizer minima are higher.) And being down early gives you a better chance to break out to visual, and maybe fly around the one cloud that would otherwise be in the way. To figure ground speed, subtract the headwind from the airspeed. It will be close enough. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top Bob Moore Guest Posted: Fri Mar 30, 2007 4:16 am    Post subject: Re: Winds on approach Bob Gardner wrote Quote: Conventional wisdom (as I see it) is to execute a miss if you lose the glideslope, go around, prepare and brief the localizer approach, then do it. Changing horses in midstream is not wise policy, especially in the clouds and close to the ground. YMMV, but I'll never teach or advocate the switch. Nor do Part 121 Aircarriers permit their aircrews to change-over. Bob Moore Back to top Tim Guest Posted: Fri Mar 30, 2007 4:24 am    Post subject: Re: Winds on approach One should always time the approach. In some senses it is easier. if the GS goes bad, just go to the minimum altitude - one less needle to keep track of. Always time it. The wx could go worse or low on fuel - why abandon the approach if you have it set up already? What you advocate makes no sense to me. What is the rationale? Bob Gardner wrote: Quote: Conventional wisdom (as I see it) is to execute a miss if you lose the glideslope, go around, prepare and brief the localizer approach, then do it. Changing horses in midstream is not wise policy, especially in the clouds and close to the ground. YMMV, but I'll never teach or advocate the switch. Bob Gardner "Jose" <teacherjh (AT) aol (DOT) nospam.com> wrote in message news:wrWOh.1128$5e2.823 (AT) newssvr11 (DOT) news.prodigy.net... You are timing your ILS approaches? Any reason for this? I can't find anything in my 172P book that suggests 90 kts as an approach speed, even in gusty winds. Seems fast to me. IF one times their ILS, and loses the glideslope, one can often convert to a localizer approach easily. And approach plates give canned timings for various speeds, 90 knots is probably the best of the bunch for a 172. Of course that's ground speed, not airspeed. Jose -- Get high on gasoline: fly an airplane. for Email, make the obvious change in the address. Back to top Tim Guest Posted: Fri Mar 30, 2007 4:25 am    Post subject: Re: Winds on approach Is that FAA or air carrier rule? That does not mean it is a bad thing. It seems to me that abandoning an approach with the risk of fuel and worse weather is worse. Bob Moore wrote: Quote: Bob Gardner wrote Conventional wisdom (as I see it) is to execute a miss if you lose the glideslope, go around, prepare and brief the localizer approach, then do it. Changing horses in midstream is not wise policy, especially in the clouds and close to the ground. YMMV, but I'll never teach or advocate the switch. Nor do Part 121 Aircarriers permit their aircrews to change-over. 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