Change Forum... Civil Aviation Travel, Polls & Prefs Tech/Ops Aviation Hobby Aviation Photography Photography Feedback Trip Reports Military Av & Space Non-Aviation Site Related LIVE Chat My Starred Topics | Profile | New Topic | Forum Index | Help | Search
 Glide Distance
 Corsair2 From United States of America, joined Jan 2001, 248 posts, RR: 0Posted Mon Jun 20 2005 16:28:29 UTC (10 years 11 months 1 week 4 days 9 hours ago) and read 11558 times:

 What is a good rule of thumb for glide distance with an engine failure in a Cessna 172 as a function of altitude? 1000 ft per mile?
 "We have clearance Clarence. Roger, Roger. What's our vector Victor?"
 KFLLCFII From United States of America, joined Sep 2004, 3433 posts, RR: 24 Reply 1, posted Mon Jun 20 2005 21:26:58 UTC (10 years 11 months 1 week 4 days 4 hours ago) and read 11494 times:

 Quoting Corsair2 (Thread starter):What is a good rule of thumb for glide distance with an engine failure in a Cessna 172 as a function of altitude? 1000 ft per mile?

Appx. 1.5 NM per 1,000 feet at best-glide speed (68 knots). This, of course, will depend on total weight, flap setting, a windmilling propeller, and zero wind. Source: C172R Information Manual, Section 3, Figure 3-1 Maximum Glide.

(Edited for source)

[Edited 2005-06-20 21:34:24]

 "About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."
 Corsair2 From United States of America, joined Jan 2001, 248 posts, RR: 0 Reply 2, posted Tue Jun 21 2005 18:36:25 UTC (10 years 11 months 1 week 3 days 7 hours ago) and read 11359 times:

 Also, what FAR's apply to the crossing of water in single engine airplane. I remember one about minimum equipment needed but can't remember which one it is to refer to it?
 "We have clearance Clarence. Roger, Roger. What's our vector Victor?"
 KFLLCFII From United States of America, joined Sep 2004, 3433 posts, RR: 24 Reply 3, posted Wed Jun 22 2005 02:32:54 UTC (10 years 11 months 1 week 2 days 23 hours ago) and read 11308 times:

 There is no equipment requirement regarding the crossing of water in a single-engine airplane unless that aircraft is operated for hire: Sec. 91.205 Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements: (b) Visual-flight rules (day). For VFR flight during the day, the following instruments and equipment are required: (12) If the aircraft is operated for hire over water and beyond power-off gliding distance from shore, approved flotation gear readily available to each occupant and at least one pyrotechnic signaling device. As used in this section, ``shore'' means that area of the land adjacent to the water which is above the high water mark and excludes land areas which are intermittently under water. In reading a required-equipment regulation farther down part 91, one may confuse this next regulation as applying to all airplanes: Sec. 91.509 Survival equipment for overwater operations. (a) No person may take off an airplane for a flight over water more than 50 nautical miles from the nearest shore unless that airplane is equipped with a life preserver or an approved flotation means for each occupant of the airplane. (b) Except as provided in paragraph (c) of this section, no person may take off an airplane for flight over water more than 30 minutes flying time or 100 nautical miles from the nearest shore, whichever is less, unless it has on board the following survival equipment: (1) A life preserver, equipped with an approved survivor locator light, for each occupant of the airplane. (2) Enough liferafts (each equipped with an approved survival locator light) of a rated capacity and buoyancy to accommodate the occupants of the airplane. (3) At least one pyrotechnic signaling device for each liferaft. (4) One self-buoyant, water-resistant, portable emergency radio signaling device that is capable of transmission on the appropriate emergency frequency or frequencies and not dependent upon the airplane power supply. (5) A lifeline stored in accordance with Sec. 25.1411(g) of this chapter. Sound convincing for all small single-engine airplanes? Sure. But when you take a step back and check the applicability of the subpart having authority over this regulation (Subpart F), you will note this: Subpart F_Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft Sec. 91.501 Applicability. (a) This subpart prescribes operating rules, in addition to those prescribed in other subparts of this part, governing the operation of large airplanes of U.S. registry, turbojet-powered multiengine civil airplanes of U.S. registry, and fractional ownership program aircraft of U.S. registry that are operating under subpart K of this part in operations not involving common carriage. Hence, this regulation ALSO does not apply to all light single-engine airplanes. So, if you are in a light single engine airplane for private use, there is no over-water equipment requirement. These regulations only apply to aircraft operated for hire, or are large, turbojet-powered multiengines, or are operated under a fractional ownership program.
 "About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."
 ATCT From United States of America, joined Mar 2001, 2593 posts, RR: 34 Reply 4, posted Wed Jun 22 2005 02:35:08 UTC (10 years 11 months 1 week 2 days 23 hours ago) and read 11305 times:

 I believe the Bahamas require overwater equipment. I dont know the reg offhand, but I believe they have one for aircraft doing the FL-Bahamsa hop.
 Trikes are for kids!
 PlainSmart From , joined Dec 1969, posts, RR: Reply 5, posted Wed Jun 22 2005 08:05:51 UTC (10 years 11 months 1 week 2 days 17 hours ago) and read 11274 times:

 The best glide distance for a power off prop happends at the L/Dmax. This is the speed where there is the lowest drag between parasite and induced. As airspeed goes up so does parasite drag. On the other hand, as airspeed goes up, induced drag ultimately goes down. For each airspeed one can calculate what the total drag for an airplane is. At one point though, there will be a smallest total drag number. The airspeed that corresponds with this total drag value is your best glide airspeed. The 172 is 68 KIAS This is the speed that you will incur the least amount of drag possible. I do not know the L/D max of the 172 although a very close cessna I worked the numbers and the L/Dmax is 10.33 which means for every NM f altitude, the airplane will travel 10.33NM. About 85 kias at sea level.
 Corsair2 From United States of America, joined Jan 2001, 248 posts, RR: 0 Reply 6, posted Thu Jun 23 2005 22:49:43 UTC (10 years 11 months 1 week 1 day 2 hours ago) and read 11166 times:

 Thanks KFLL CFII. I didn't realize that the equipment requirement was for commercial operations. The trip I had in mind (Apostle Islands in Lake Superior) involves a short crossing of water (4-5 miles). Now I realize that all I need to do is fly >3000 ft and use some reasonable caution based on the wind conditions that day. If I were wanting to cross all the way across Lake Michigan (> 60mi) it would be wise to get a life preserver even though it is not required. Not a pretty situation to be stuck in the middle of Lake Michigan!
 "We have clearance Clarence. Roger, Roger. What's our vector Victor?"
 KFLLCFII From United States of America, joined Sep 2004, 3433 posts, RR: 24 Reply 7, posted Thu Jun 23 2005 23:30:44 UTC (10 years 11 months 1 week 1 day 2 hours ago) and read 11156 times:

 Quoting Corsair2 (Reply 6):If I were wanting to cross all the way across Lake Michigan (> 60mi) it would be wise to get a life preserver even though it is not required. Not a pretty situation to be stuck in the middle of Lake Michigan!

Not at all! For that trip I would also recommend renting a life raft (if such a service exists in your area), a flare gun with an adequate supply of flares, and a hand-held transceiver packed in a waterproof case with many sets of spare batteries. Prepare for the worst, hope for the best!

 "About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."
 B744F From Germany, joined Jan 2006, 0 posts, RR: 0 Reply 8, posted Fri Jun 24 2005 03:49:09 UTC (10 years 11 months 1 week 21 hours ago) and read 11139 times:

 Pilots practice water landing procedures but most know going down in water means almost certain death. There are life preservers and rafts on airplanes but they do little good unless you are just having a lucky day.
 KFLLCFII From United States of America, joined Sep 2004, 3433 posts, RR: 24 Reply 9, posted Fri Jun 24 2005 05:05:38 UTC (10 years 11 months 1 week 20 hours ago) and read 11131 times:

 Quoting B744F (Reply 8):There are life preservers and rafts on airplanes but they do little good unless you are just having a lucky day.

Adding to that, the best type of life preserver is the inflatable "vest" type, which can be worn in flight with little interference. Should you have to make an emergency egress into the water, you already have it donned, and all that's required is a tug on the CO2 cord to inflate. But you are right regarding the raft; They can be bulky, and can be difficult to get out of the plane if it's rapidly sinking. However, I'd rather have one onboard with the chance I may or may not be able to utilize it than not having one at all.

PS - 300th Post!

 "About the only way to look at it, just a pity you are not POTUS KFLLCFII, seems as if we would all be better off."
 Sccutler From United States of America, joined Jan 2000, 6062 posts, RR: 26 Reply 10, posted Sun Jul 3 2005 00:32:15 UTC (10 years 10 months 4 weeks 1 day 1 hour ago) and read 10979 times:

 Quoting B744F (Reply 8):Pilots practice water landing procedures but most know going down in water means almost certain death. There are life preservers and rafts on airplanes but they do little good unless you are just having a lucky day.

This may well be true for large, transport category aircraft, but in general aviation aircraft, nearly all ditchings are survivable, and the aircraft usually remains afloat for long enough to get out and into such flotation gear as you may have. I hope never to provide the proof myself, but I know people who have ditched and survived to tell all.

 ...three miles from BRONS, clear for the ILS one five approach...
 DH106 From United Kingdom, joined Jun 2005, 627 posts, RR: 2 Reply 11, posted Sun Jul 3 2005 01:13:41 UTC (10 years 10 months 4 weeks 1 day ago) and read 10976 times:

 Quoting PlainSmart (Reply 5):The 172 is 68 KIAS This is the speed that you will incur the least amount of drag possible. I do not know the L/D max of the 172 although a very close cessna I worked the numbers and the L/Dmax is 10.33 which means for every NM f altitude, the airplane will travel 10.33NM. About 85 kias at sea level.

Min Drag Speed = Min sink/Max Duration
Max L/D = Max range

As PlainSmart quotes, for a C172, 68KIAS give you min sink/max duration and 85KIAS gives max range achievable albeit in less time. So when your engine stops, an assessment of how terminal it is will dictate which of these to adopt.

 ...I watched c-beams glitter in the dark near the Tanhauser Gate....
 Corsair2 From United States of America, joined Jan 2001, 248 posts, RR: 0 Reply 12, posted Mon Jul 18 2005 15:40:58 UTC (10 years 10 months 1 week 6 days 10 hours ago) and read 10723 times:

 Thanks for all the good posts on this. I have always wondered too when flying along Lake Michigan (within glide distance of shore) how easy it would be to get out of a Cessna 172 if it went down in the water. How would one get the door open in the water and then get out given the possibility of the high wing being an obstacle. Water evacuation is something not practiced in our training but would be worth knowing how to do.
 "We have clearance Clarence. Roger, Roger. What's our vector Victor?"
 Top Of Page Change Forum... Civil Aviation Travel, Polls & Prefs Tech/Ops Aviation Hobby Aviation Photography Photography Feedback Trip Reports Military Av & Space Non-Aviation Site Related LIVE Chat Forum Index

Reply To This Topic Glide Distance
• Tech/Ops related posts only!
• Not Tech/Ops related? Use the other forums
• No adverts of any kind. This includes web pages.
• No hostile language or criticizing of others.
• Do not post copyright protected material.
• Use relevant and describing topics.
• Check if your post already been discussed.
• Check your spelling!
• DETAILED RULES

Please check your spelling (press "Check Spelling" above)

 Similar topics: More similar topics...
Help, FAA Landing F.L. & Real Landing Distance posted Tue Sep 26 2006 04:03:45 by AGANX
Contrail Horizon To Horizon? What Distance? posted Sat Jun 17 2006 02:35:04 by Ba757gla
Runway Distance Markers - When/Why? posted Sat Apr 29 2006 20:56:47 by AeroWesty
Max Distance For The Concorde? posted Tue Mar 28 2006 17:39:51 by 747LUVR
Landing Distance And Autobrakes posted Wed Nov 23 2005 21:40:53 by Julesmusician
C130 Stopping Distance posted Fri Oct 21 2005 18:38:52 by Gary2880
Climb Rate And Distance From LHR posted Sat Jan 15 2005 22:43:32 by Ba97
Shortest Stopping Distance On An Airliner posted Sat Jan 1 2005 14:54:17 by Soaringadi
ILS Glide Path Setup posted Tue Dec 21 2004 01:26:47 by TBA04
Distance To Fan On Jet Engines posted Mon Dec 20 2004 07:15:02 by Videns
How Accurate Of Runway Distance Markers? posted Thu Aug 18 2011 09:40:07 by DFWHeavy
Distance From Runway For 'Gear Down' posted Sat Sep 18 2010 01:55:08 by nema
Take-off Distance Requirements Question posted Tue Sep 14 2010 04:38:30 by kiwiflyer1
Distance To Destination Calculations? posted Wed Jul 14 2010 21:03:52 by wardialer
77W Takeoff Distance posted Wed May 26 2010 09:34:52 by mhockey31091
Why No Published Best Glide In Light Twins? posted Thu Nov 6 2008 01:04:51 by Bassbonebobo
Minimum Distance Allowed For Parallel Runways? posted Tue Jun 17 2008 13:22:04 by 8herveg
ULR's Unefficient With Distance? posted Tue Feb 12 2008 13:35:55 by Faro