# Flyers, what are "oleos"? **URL:** \ **Category:** Factual Questions\ **Created:** [June 10, 2003, 4:03pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890 "2003-06-10T16:03:29Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\ **Post date:** [June 10, 2003, 4:03pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/1 "2003-06-10T16:03:29Z")
On the NTSB web site, they have a description of an “incident” that occurred on March 4, 1994 when a China Airlines 747 tried to take off with the parking brake engaged. A summary is here, [http://www.ntsb.gov/ntsb/brief.asp?ev\_id=20001206X00827&key=1](http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001206X00827&key=1) > [@](#): > > The B747 began takeoff roll with parking brake engaged. The runway was covered with patches of ice, at approximately 60 knots, during engine accelleration [sic] in autothrottle mode, a caution panel warning light indicated parking valve was not open. The pilot rejected takeoff; however, 16 main tires blew out and ground down the wheels to the oleos as they dragged on dry pavement. > > [Changed from all upper case to improve readability.] What are the “oleos” referred to above? My dictionary only lists the usual definition of oleo: “margarine”. ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [June 10, 2003, 4:44pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/2 "2003-06-10T16:44:01Z")
From a bit of Googling, it appears that “oleos” are the name for the lower portion of the main strut which is the landing gear shock absorber. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [June 10, 2003, 4:56pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/3 "2003-06-10T16:56:55Z")
IIRC it is so named because it is filled with oil (an oil/air mix??) Brian ---
**Author:** ![Race\_Bannon](https://avatars.discourse-cdn.com/v4/letter/r/5f8ce5/32.png) [@Race\_Bannon](https://boards.straightdope.com/u/Race_Bannon)\ **Post date:** [June 10, 2003, 5:03pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/4 "2003-06-10T17:03:10Z")
rsa is correct. The oleo strut is the shock absorbing mechanism used in many aircraft landing gear. I think that a more complete word might be oleo-pneumatic. Struts like this use a combination of compressed air and oil to provide stiffness and damping. I think the oleo comes from oleoresin, a kind of oil. ---
**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\ **Post date:** [June 10, 2003, 6:36pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/5 "2003-06-10T18:36:24Z")
Thanks, guys. I must say, for pure drama expressed in utterly dry, technical prose, you can’t beat that NTSB site… ---
**Author:** ![Llama\_Llogophile](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@Llama\_Llogophile](https://boards.straightdope.com/u/Llama_Llogophile)\ **Post date:** [June 10, 2003, 7:19pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/6 "2003-06-10T19:19:18Z")
> [@](#): > > \*Originally posted by chukhung \* > \*\*I must say, for pure drama expressed in utterly dry, technical prose, you can’t beat that NTSB site… \*\* Slight hijack here: The NTSB is hilarious in some instances when describing accidents. I read one about a plane that had to make an emergency landing because the propeller fell off. The phrasing in the accident report was: “During level flight at 5,500 feet, the propeller departed the aircraft.” Sounds almost pastoral doesn’t it? It just… departed. **THE FREAKIN’ THING FELL OFF THE FREAKIN’ AIRPLANE!!!** They crack me up over there at the NTSB. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [June 11, 2003, 10:19am UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/7 "2003-06-11T10:19:38Z")
Ah, those wacky guys at NTSB. I was once on an airplane during an “incident” - smoke and fire pouring off a wing, people screaming, airplane jerking around, etc. Went back and read the NTSB report. When reading, it seemed so… so… calm and uneventful. You have to sort of key words like “departed” standing in for “parts fell off the freakin’ plane” and such. They never say stuff like “crashed, forming a small crater and parts were found in the next county”, it’s “impacted, with a substantial debris field” And, yes, by the way, “oleos” are the oil-filled part of the shock-absorbing strut(s) on the landing gear. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 11, 2003, 1:08pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/8 "2003-06-11T13:08:40Z")
> [@](#): > > **THE FREAKIN’ THING FELL OFF THE FREAKIN’ AIRPLANE!!!** Erm… I’ve been known to say “departed the aircraft”. :o What cracks me up is when they conclude that the reason the airplane crashed is that is hit the ground. (Just got up, so I don’t recall how they say it exactly.) I don’t remember the NTSB saying stuff like, “The pilot was killed.” They seem to like to say things like, “The pilot suffered fatal injuries.” Th OP has been answered; but for general information, light aircraft often have tubular or flat spring steel landing gear struts. For example, Cessnas have spring steel struts (flat ones until about 1971, and tubular after that) on the main gear and an oleo strut on the nose. Some airplanes like the Piper J-3 Cub used bungees for shock absorbtion. Question: Are trailing link landing gear struts considered oleo struts? They have an oleo component, but it’s more like a shock absorber on a car. ---
**Author:** ![Race\_Bannon](https://avatars.discourse-cdn.com/v4/letter/r/5f8ce5/32.png) [@Race\_Bannon](https://boards.straightdope.com/u/Race_Bannon)\ **Post date:** [June 11, 2003, 1:30pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/9 "2003-06-11T13:30:56Z")
Johnny, I’ve seen words like “controlled flight into terrain”. Funniest thing I’ve seen in a (Army) mishap report was for a birdstrike incident. In the section for injuries/fatalities, some wiseacre wrote “One Quail, DOA, Runway 19”. As for the tailwheel, I can’t say I usually hear people refer to it as “oleo” but if it is an oil/air device, the word fits. And I should mention that in helicopters, the oleos have another improtant function, they provide damping to prevent ground resonance. ---
**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\ **Post date:** [June 11, 2003, 8:08pm UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/10 "2003-06-11T20:08:06Z")
Well, I suppose this post probably belongs in MPSIMS–but what the heck. I like a good hijack as much as the next guy. I’ve been reading a lot of the [major aviation accident reports](http://www.ntsb.gov/Publictn/A_Acc1.htm) at the NTSB site recently and I’ll just post some comments–but please note that I’m not an aviator and anything I write below may well be wrong, technically. > [@](#): > > \*Originally posted by Race Bannon \* > \*\*Johnny, I’ve seen words like “controlled flight into terrain”. \*\* As far as I know, the NTSB only uses that term when the pilot has control of the airplane but doesn’t realize his altitude or the elevation of the terrain and hits the ground while still in full control (although, control is usually lost pretty darn quickly after that…). That scenario actually seems to happen relatively frequently with airline accidents. I guess by the time a someone gets his “airline transport pilot” certificate, it’s a pretty rare thing to actually lose control of a fully functional aircraft. The NTSB will actually use the word “crash” in some reports, for example in this [summary](http://www.ntsb.gov/publictn/2002/AAR0201.htm) of the Alaska Airlines Flight 261 accident: > [@](#): > > On January 31, 2000, about 1621 Pacific standard time, Alaska Airlines, Inc., flight 261, a McDonnell Douglas MD-83, N963AS, crashed into the Pacific Ocean about 2.7 miles north of Anacapa Island, California. Other times, though, they’ll use bizarre circumlocutions such as in this [abstract](http://www.ntsb.gov/publictn/1997/AAR9702.htm) of the crash that ended 7-year-old Jessica Dubroff’s attempt to be the youngest “pilot” to fly across the continental U.S. > [@](#): > > This report explains the accident involving a Cessna 177B airplane that collided with terrain after a loss of control following takeoff from runway 30 at the Cheyenne Airport, Cheyenne, Wyoming, on April 11, 1996. If you want to get the full drama of these reports, I’d suggest starting with the cockpit voice recorder (CVR) transcript if it’s available (usually it’s in Appendix B of the full report). Read that first and then read the rest of the report to figure out what acually happened. Sometimes you can tell things are going bad well before the accident. For example in the CVR transcript of Korean Air Flight 801 that crashed while trying to land in Guam on August 6, 1997, it’s obvious that the crew is confused about the glideslope > [@](#): > > Despite several indications that the flight crew was aware that the glideslope was inoperative, in the last 2 ½ minutes of the flight (beginning shortly after the airplane was established on the approach), the CVR recorded a series of conflicting flight crew comments concerning the operational status of the glideslope. About 0139:55, the flight engineer asked, “is the glideslope working?” The captain responded, “yes, yes it’s working.” About 0139:58, an unidentified voice in the cockpit stated, “check the glideslope if working?” One second later, an unidentified voice in the cockpit stated, “why is it working?” About 0140:00, the first officer responded, “not useable.” About 0140:22, an unidentified voice in the cockpit stated, “glideslope is incorrect,” followed by the captain’s statement, “since today’s glideslope condition is not good, we need to maintain one thousand four hundred forty [feet].” However, about 0141:46, after the airplane crossed the GUQQY outer marker (1.6 DME from the VOR), the captain again stated, “isn’t glideslope working?” When you read the CVR transcript and see the Guam center controller say to Flight 801, “glide slope unusable”, you keep wanting to shout to the pilot: “It’s not working! Fly the freaking plane and forget about it!” Other times, though, it’s hard for a layperson to know exactly when things started to go bad just by reading the CVR transcript. For example, when, on December 19, 1996, Continental Airlines Flight 1943 did a wheels up landing at Houston Intercontinental, things seems to be going smoothly at the start of the transcript. Unless you happened to understand that when the crew was doing the “in-range checklist” they skipped over the fourth item on the list: “hydraulics”. Without high-pressure hydraulics on a DC-9, the flaps don’t come down and the wheels stay up. Oops. Of course, some CVR transcripts are just boring. TWA Flight 800 was flying along without problems and then, all of a sudden, > [@](#): > > 2030: 42 > CAM (( sound similar to a mechanical movement in cockpit)) > > 2031: 03 > CAM \*. > > 2031: 05 > CAM (( sounds similar to recording tape damage noise)). > > 2031: 12 > end of recording. While most of the drama is often in the CVR transcripts, the reports themselves can be fascinating as well. For example, take a look at the photos included in the [full report](http://www.ntsb.gov/publictn/2002/AAR0201.pdf) of the crash of Alaska Airlines Flight 261. When you see the stripped out threads wrapped around the horizontal stabilizer jackscrew or see the cross section of the acme nut (with nothing but a smoothed off helical pattern where the threads should have been), you don’t have to be an expert to conclude “that’s pretty f\*\*\*ed up right there, dude.” The best reports are the ones where everybody walks away. My favorite is the [report](http://www.ntsb.gov/publictn/1996/AAR9605.pdf) on American Flight 1572 hitting the trees on a ridge before (barely) making it to Bradley International Airport at Windsor Locks, Connecticut. You almost feel like cheering when you see the co-pilot say, “God bless you, you made it.” Unfortunately, though, most of the reports are just tragedies. No real villains (there are no reports for the 9/11 crashes), just mechanical problems and human beings who get confused or forgetful and screw up. They make you think… ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [June 12, 2003, 12:06am UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/11 "2003-06-12T00:06:53Z")
Quick! Post before the mods close the hijacked thread! Hurry-hurry-hurry! > [@](#): > > _Originally posted by chukhung_ > > > [@](#): > > > > \*Originally posted by Race Bannon \* > > Johnny, I’ve seen words like “controlled flight into terrain”. > > As far as I know, the NTSB only uses that term when the pilot has control of the airplane but doesn’t realize his altitude or the elevation of the terrain and hits the ground while still in full control (although, control is usually lost pretty darn quickly after that…). That scenario actually seems to happen relatively frequently with airline accidents. I guess by the time a someone gets his “airline transport pilot” certificate, it’s a pretty rare thing to actually lose control of a fully functional aircraft. I’d say by the time you hit “commercial” or 500 hours of just plain experience “lost of control” gets pretty darn rare, assuming an intact airplane and decent weather. A lot of the “loss of control” and “controlled flight into terrain” (CFIT) involves flight in instrument weather conditions - that is, clouds and/or fog, or severe storms. In clouds, the only thing keeping you upright and on course are your instruments and your ability to use them properly - if either the instruments fail, or the pilot fails to heed what they are saying you can get some very tragic things happening. Severe storms, in and of themselves, can have conditions that can either damage the aircraft or destroy it. A third category involves what can only be called stupid human tricks - flying too low, low-level stunt flying, and other hijicks that carry a high risk of painful outcome. > [@](#): > > _Originally posted by chukhung_ > Other times, though, they’ll use bizarre circumlocutions such as in this abstract of the crash that ended 7-year-old Jessica Dubroff’s attempt to be the youngest “pilot” to fly across the continental U.S. > > > [@](#): > > > > This report explains the accident involving a Cessna 177B airplane that collided with terrain after a loss of control following takeoff from runway 30 at the Cheyenne Airport, Cheyenne, Wyoming, on April 11, 1996. Well, there’s a classic case of stupid human tricks - the CFI responsible for that flight had the following against him: [list=1] [li]He wasn’t used to flying at high altitude - most of his flying started from sea level or nearly so, not from the elevation of Cheyenne, WY[/li][li]The airplane was overloaded and probably out of balance[/li][li]There was a very unrealistic time schedule involved - their plan called for flying from California to the Atlantic in a C177 in _three days_. I have friends who have made “mere” 1800-2000 mile journies in comparable planes and budgeted a _week_.[/li][li]The weather was bad - they required a “special VFR” clearance from the tower, meaning instrument conditions. IIRC, there was freezing rain at the time - a VERY dangerous weather phenomena that can take down a much larger and better-equipped plane than what they had[/li][/list=1] Any one of the above could have caused or contributed to an accident - all four at once was asking for serious trouble. > [@](#): > > _Originally posted by chukhung_ > While most of the drama is often in the CVR transcripts, the reports themselves can be fascinating as well. For example, take a look at the photos included in the full report of the crash of Alaska Airlines Flight 261. When you see the stripped out threads wrapped around the horizontal stabilizer jackscrew or see the cross section of the acme nut (with nothing but a smoothed off helical pattern where the threads should have been), you don’t have to be an expert to conclude “that’s pretty f\*\*\*ed up right there, dude.” Yep. When a non-mechanic spots a problem that obvious you KNOW there’s a problem! My all time favorite recording from a crash was when Capt Al Hayes was approaching the Sioux City airport (this is the DC-10 that lost all hydraulics, _almost_ made it to the ground before cartwheeling, and 2/3 of the people still survived). Keep in mind, they _barely_ have control of the airplane: Tower: You are cleared for any runway Hayes: Oh, you’re going to get particular and insist we land on a runway? (any errors in quoting due to my faulty recollections) ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 12, 2003, 12:57am UTC](https://boards.straightdope.com/t/flyers-what-are-oleos/180890/12 "2003-06-12T00:57:21Z")
> [@](#): > > As for the tailwheel, I can’t say I usually hear people refer to it as “oleo” but if it is an oil/air device, the word fits. Was this in reference to my question about trailing link landing gear? When I think of an oleo strut, I think of a linear thing. There is a “shock absorber”-like strut with an axle on the bottom. A trailing link landing gear is more complicated. There is a link at the bottom of the vertical strut where a pivoting, trailing arm is attached. The wheel is attached to the end of the trailing arm. There is a “shock absorber” connecting the trailing arm to a point above the pivot on the vertical strut. I tend to think of oleo struts and trailing link landing gear as different things; but the trailing link clearly does have an oleo strut to absorb shock. > [@](#): > > 2.The airplane was overloaded and probably out of balance Not to mention that the C-177 Cardinal was notoriously under-powered.