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 |
#31
|
|||
|
|||
MSL vs. AGL (Again)
Oh boy...this sounds serious. Why is the altimeter involved in the landing in any way in the pattern? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl AGREED!, today on a rough thermal tow day with thermal induced turbulance and slack lines on tow, and after my student had a great "learn to center the thermal and climb" day, just sitting quiet in the back seat and let him learn by doing, toughest thing an instructor has to do. Then some review of all the stalls down to pattern and landing. On the second tow, just as we reached 2K AGL, on an MSL set altimeter, I took control of the glider on tow and gave him two suction cups to cover the altimeter and airspeed. As soon as they were set, I pulled the release, turned off tow and "Your airplane". He tripped into a thermal and climbed, and then I said, let's go home. Determining pattern altitude entry based on what it looks like, controlling airspeed by pitch reference to the horizon and sound of the wind over the canopy. An excellent pattern and landing. He is ready to solo. T |
#32
|
|||
|
|||
MSL vs. AGL (Again)
On Jul 16, 11:30*am, Chris Donovan wrote:
On Jul 15, 9:57*pm, "John Godfrey (QT)" wrote: On Jul 15, 9:37*pm, Eric Greenwell wrote: On 7/15/2011 1:16 PM, T8 wrote: On Jul 14, 10:20 pm, *wrote: The MSL/AGL issue has come before the Caesar Creek Soaring Club Board once again. Not only has the Club been thrown into turmoil again, this time it has specifically affected our instructors and how to most effectively teach our students. I am curious if there are other Clubs or organizations that teach using AGL. Rolf Hegele Member of the Board Is there even *one* good argument for setting the altimeter to zero on the runway? You live anywhere in Florida? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) I still think there is hope... Consider (from Wikapedia) Railway time was the name given to the standardised time arrangement first applied by the Great Western Railway in England in November 1840. This was the first recorded occasion when a number of different local times were synchronised and a single standard time applied. Railway time was progressively taken up by all of the other railway companies in Great Britain over the following two to three years. The times schedules by which trains were organised and the times train stations clocks displayed was brought in line with the local time for London or "London Time". This was also the time set at Greenwich by the Royal Observatory, Greenwich which was already widely known as Greenwich Mean Time or (GMT). The development of railway networks in India around 1860,[1] and North America in the 1850s,[2] as well as other countries in Europe, also prompted the introduction of standard time systems influenced by the specific, geographical, industrial development and political governance appertaining. The key purpose behind introducing railway time was twofold. Firstly, to overcome the confusion caused by having non-uniform local times in each town and station stop along the expanding railway network and secondly, to reduce the incidence of accidents and near misses which were increasingly occurring as the number of train journeys increased. The railway companies sometimes faced concerted resistance from groups of local people in a number of places where trains stopped, who refused to agree to adjust their public clocks to bring them into line with London Time. As a consequence two different times would be displayed in the town and in use with the station clocks and published in train timetables differing by several minutes from that on other clocks. Despite this early reluctance, railway time rapidly became adopted as the default time across the whole of Great Britain although it still took until 1880 for the government to legislate on the establishment of a single Standard Time and a single time zone for the country- Hide quoted text - - Show quoted text - Generally by the time a pilot gets about a hundred hours or so this discussion resolves itself! * Which is about the amount of time it takes when most Sailship pilots begin to wander from home field anyways....did you like the "sailship pilots" word I just thought up? * *Teach what the student can absorb at the time, and newbies need to absolutly know where they are in reference to the ground and not making mental calculations at every turn in the pattern! Additionally teach common sense first, keep your ****ing head on a swivil and out side of the cockpit not playing with computers and vario's at critical moments.- Hide quoted text - - Show quoted text - Intelligent. And... During the first instruction flight, and all other instruction flights for that matter, the student doesn't NEED to know anything, that is what the instructor is for. If the student cannot handle a particular task, say MSL altimeter calculations for example, then don't teach it at all until they can. Then, when they have learned ALL of the required skills they are ready for solo. |
#33
|
|||
|
|||
MSL vs. AGL (Again)
On Jul 16, 5:11*am, Burt Compton - Marfa wrote:
Now operating at Marfa, Texas (elevation 4849' MSL), Respectfully, If you are flying out of Marfa Texas, you cannot set "0" for AGL flying. The altimeter does not unwind that far. T |
#34
|
|||
|
|||
MSL vs. AGL (Again)
Is there even *one* good argument for setting the altimeter to zero on
the runway? -Evan Ludeman / T8 I learned how to fly at Caesar Creek Soaring Club (nee Soaring Society of Dayton operating out of Richmond, Indiana) in 1965. As now, the club used an altimeter setting of zero on the runway (AGL/QFE). I did, too, for years--with a lot of cross country hours--because I flew only in the Midwestern U.S. where the greatest difference between takeoff and landing altitude was a few hundred feet. I referred to those quaint Sectional charts we used for navigation back then to look up the field elevation at other airports, which I would have done anyway even if using MSL/QNH. There was a lot less controlled airspace so I almost never talked a tower, ATC, or powered aircraft. Most of the time, the altimeter told me about how high I was above the terrain. If it looked closer, I used judgment to gauge when it was time to land, just as I do today. I can't remember when I made the switch to MSL/QNH for all the right reasons. It wasn't a big deal. I'm sure using AGL/QFE was easier when I was an early student--one less thing to worry about--but that's something the instructor could have covered for me until I could learn, just as he compensated for my poor takeoff and landing skills initially. The biggest reasons AGAINST switching to MSL/QNH earlier were, interestingly enough, related NOT to staying around the home airport but to flying cross country and, especially, contests: 1. Start and finish gate altitudes were set AGL. In the olden days when we dove at high speed across a line on the ground, it was slightly easier to judge how far above or below the max height one might be when the big hand on the altimeter was unwinding towards zero and the hand on the ASI was hovering near redline (ah, the good old days....). 2. Final glides were MUCH easier to monitor. In those pre-computer days, I would sit in the cockpit with my cardboard calculator in my left hand monitoring landmarks as I flew on and comparing altitude needed with actual altitude above the finish line read directly from my altimeter. No subtraction required. After I made the switch to MSL/QNH, for a while copied a technique I'd read about some pilots using at the Worlds: i.e., I set my altimeter on zero on the grid and wrote down the pressure setting, then immediately set it back to field elevation. On final glide, I would reset the altimeter to the zero pressure setting (AGL/QFE) again so I could monitor altitude above the finish line. That worked well until I started flying out West where, as some have pointed out, higher field elevations made it impossible to reset the altimeter to zero. I read of at least one world-class pilot who installed two altimeters in the cockpit, one set to AGL/QFE and the other to MSL/QNH! With the advent of final glide computers, I no longer needed my cardboard calculator. I still carry it in the cockpit, however, and occasionally pull it out to "common sense" the numbers coming out of the computer. When I do, I mentally do the subtraction to determine my actual altitude above the goal and am thankful for all the technology that makes this decision such a no-brainer to younger pilots. Chip Bearden ASW 24 "JB" USA |
#35
|
|||
|
|||
MSL vs. AGL (Again)
N11rdbird wrote:
The MSL/AGL issue has come before the Caesar Creek Soaring Club Board once again. Not only has the Club been thrown into turmoil again, this time it has specifically affected our instructors and how to most effectively teach our students. I am curious if there are other Clubs or organizations that teach using AGL. Rolf Hegele Member of the Board I was taught that it is up to the. pilot in command. When flying around the local airport, agl zero is fine. when flying cross country, MSL zero is standard practice but not necessarily reliable since you do not know where you will be landing. |
#36
|
|||
|
|||
MSL vs. AGL (Again)
On 7/19/2011 12:10 PM, Tom Stock wrote:
wrote: The MSL/AGL issue has come before the Caesar Creek Soaring Club Board once again. Not only has the Club been thrown into turmoil again, this time it has specifically affected our instructors and how to most effectively teach our students. I am curious if there are other Clubs or organizations that teach using AGL. Rolf Hegele Member of the Board I was taught that it is up to the. pilot in command. When flying around the local airport, agl zero is fine. when flying cross country, MSL zero is standard practice but not necessarily reliable since you do not know where you will be landing. You've stated a couple of things in ways that aren't familiar to me. What does "MSL zero" mean? Or maybe you meant "set it to field elevation"? And why would it be more reliable if you knew where you were landing? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#37
|
|||
|
|||
Believe it or not, a major American airline flew using what I would label as "blended" QFE procedures for departure, approach and landing until ~mid 90's. Three altimeters in the cockpit, the one's directly in front of the pilots would be reset to QFE below approx. 10,000 AGL, the center would be used to comply with ATC clearances in MSL.
The logic given for QFE use was to "standardize" the CAT I ILS Decision Height for EVERY airport flown into 200' AGL and to enhance altitude awareness above terrain. Special altimeters were installed to allow the extra adjustment needed to fly into high altitude airports such as ABQ, DEN, JAC and the like. The company transitioned over to QNH in the 90's to standardize with the industry and save $$$ on the altimetry costs and training. As you can imagine, it made for some interesting instrument crosschecks inflight and puzzled looks when guests jumpseated in the cockpit. Thanks for the trip down memory lane.... Rob ps-teaching "ab initio"...QFE procedures...in today's airspace and traffic environment...does a disservice to the student and is potentially dangerous. My 2 cents... Last edited by RAS56 : July 19th 11 at 10:25 PM. |
#38
|
|||
|
|||
MSL vs. AGL (Again)
On Jul 20, 3:21*am, Chip Bearden wrote:
After I made the switch to MSL/QNH, for a while copied a technique I'd read about some pilots using at the Worlds: i.e., I set my altimeter on zero on the grid and wrote down the pressure setting, then immediately set it back to field elevation. On final glide, I would reset the altimeter to the zero pressure setting (AGL/QFE) again so I could monitor altitude above the finish line. I've only done a couple of comps, and in a low performance glider (PW5) but something I thought obvious, and found useful, was to annotate the task sheet before launch with the MSL height needed at the last few turnpoints for a final glide at McCready 0, 2, or 4. And maybe also at a few landmarks along the way. I also wrote down the distance to run from each turnpoint. There was one day that absolutely died, but I managed to get one final slow scratching climb and then final glide at M=0 (with a 500 ft safety height) from 3 turnpoints out. Which, to be fair, was only about 50 km. |
#39
|
|||
|
|||
MSL vs. AGL (Again)
Eric Greenwell wrote:
On 7/19/2011 12:10 PM, Tom Stock wrote: wrote: The MSL/AGL issue has come before the Caesar Creek Soaring Club Board once again. Not only has the Club been thrown into turmoil again, this time it has specifically affected our instructors and how to most effectively teach our students. I am curious if there are other Clubs or organizations that teach using AGL. Rolf Hegele Member of the Board I was taught that it is up to the. pilot in command. When flying around the local airport, agl zero is fine. when flying cross country, MSL zero is standard practice but not necessarily reliable since you do not know where you will be landing. You've stated a couple of things in ways that aren't familiar to me. What does "MSL zero" mean? Or maybe you meant "set it to field elevation"? And why would it be more reliable if you knew where you were landing? Sorry, typing on my iphone, made a few edits but did not proof read it again.. |
Thread Tools | |
Display Modes | |
|
|