TymnBalewne From United States of America, joined Mar 2005, 798 posts, RR: 0 Posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12395 times:
I vaguely remember seeing movies from the early days of jets where when an engine catches fire and the firebottles are unable to extinguish the blaze, the cockpit had the ability to jettison the engine. (Of course I can't remember a movie's title but my mind visualizes a 707 in peril).
Could 707's and DC-8's actually jettison an engine? Can modern-day aircraft jettison engines?
Stitch From United States of America, joined Jul 2005, 23614 posts, RR: 79 Reply 1, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12406 times:
I know modern day aircraft cannot, and I'd be very surprised if this was a feature on any aircraft - civilian or military.
Mmedford From United States of America, joined Nov 2007, 417 posts, RR: 8 Reply 2, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12368 times:
jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
BMI727 From United States of America, joined Feb 2009, 11545 posts, RR: 27 Reply 3, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12303 times:
Quoting Mmedford (Reply 2): jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
That was not a CG issue. When the engine went the hydraulics on that side lost pressure, either due to the loss of the engine or damage to the area around it. (I think it was the damage, but I don't remember for sure) When that happened, the slats on that side retracted causing that wing to stall and the plane to roll over and crash.
The El Al 747 in Amsterdam was also not a CG problem but the loss of the engines damaged the leading edge of the wing. When they tried to slow down to make an emergency landing, the damaged wing stalled and the aircraft went in.
Quoting Stitch (Reply 1): I know modern day aircraft cannot, and I'd be very surprised if this was a feature on any aircraft - civilian or military.
I've never heard anything about an engine jettison system. I would be shocked if it existed.
On a somewhat tangential note, I do recall that the 707 (Dash 80 actually at the time) was originally going to have its engines in pairs, like on the B-52 but this was changed when engineers worried that an uncontained failure of one engine could potentially destroy both.
Why do Aerospace Engineering students have to turn things in on time?
71Zulu From United States of America, joined Aug 2006, 2334 posts, RR: 1 Reply 4, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12280 times:
Quoting Mmedford (Reply 2): jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
Well, that aircraft rolled into the lost engine. Seems like if would have made that much of a difference, it would have rolled the other way. Plus aircraft have lost an engine in flight before and landed safely, a Kalitta 747 and a NW 727 come to mind, so don't think it is anything that can't be handled as far as CG is concerned.
ZANL188 From United States of America, joined Oct 2006, 2991 posts, RR: 0 Reply 5, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12271 times:
Many Boeings have fuses in the engine mounting system that will allow the engine to depart cleanly in certain circumstances...
Theory being that it's better to let the engine go than possibly sustain damage to the aircraft structure.
Legal considerations provided by: Dewey, Cheatum, and Howe
SPREE34 From United States of America, joined Jun 2004, 1991 posts, RR: 10 Reply 6, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12246 times:
Quoting 71Zulu (Reply 4): Well, that aircraft rolled into the lost engine. Seems like if would have made that much of a difference,.......
The DC-10 rolled into the side with less lift. Less lift because the slats were retracting as a result of lost hydraulic pressure. The only part the engine played in that, was ripping out the hydraulic lines.
I don't understand everything I don't know about this.
As others have said, I don't think there ever has been a commercial type with provision to allow the crew to jettison engines. 747's are equipped with fuse pins in the struts however, so an engine could "tear away" if it subjected the strut to immense forces.
There was the case of BOAC flight 712, which suffered an engine failure shortly after takeoff. A fire ensued which eventually become hot enough to structurally weaken the strut to the point where the engine came away.
Nwarooster From United States of America, joined Feb 2005, 677 posts, RR: 3 Reply 8, posted (2 years 5 months 1 week 6 days 2 hours ago) and read 12200 times:
If an aircraft has an engine that becomes so out of balance that it shakes itself to the point that it could cause the failure of the wing, it will break free and fall off the aircraft.
There are what is called fuse pins that hold the engine to the wing or side of an aircraft.
They are designed to break and let the engine fall off the aircraft before any other serious damage could occur to the aircraft. The hydraulic and fuel line automatically seal in the pylon when this happens.
Tofen From Sweden, joined Feb 2009, 46 posts, RR: 0 Reply 9, posted (2 years 5 months 1 week 6 days 1 hour ago) and read 12177 times:
Quoting Mmedford (Reply 2): jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
Still, probably more pleasant than having that fire spreading up to the wing and reaching the fuel tank.
There's quite many airliners that have landed with one engine less than they had when they took of. The Kalitta B742 as well as the Nationwide B732 a few years ago comes to mind.
Even if they don't have "jettison systems", most planes have enginemounts designed to brake off in extreme conditions.
DenverDanny From United States of America, joined Sep 2007, 190 posts, RR: 0 Reply 10, posted (2 years 5 months 1 week 6 days 1 hour ago) and read 12177 times:
I remember reading in one of my aircraft disaster books that some aircraft have the pylons or pins connecting them to the engine that when there is a fire, it burns through the pin or pylon and the engine is freed from the plane. I think they are magnesium or something. I should run downstairs and look at my disaster book. Hold on... stomp stomp stomp... stomp stomp stomp OK so Chapter 7 Air Disaster Volume 1 by Macarthur Job, On April 8 1968, a BOAC 707 lost its number 2 engine. Aircraft had "magnesium alloy engine pylon...designed to burn through in the event of an uncontrolled engine fire, allowing the complete engine pod to drop off before damage is done to primary wing structure."
Alphaomega From United States of America, joined Aug 2005, 461 posts, RR: 0 Reply 11, posted (2 years 5 months 1 week 5 days 19 hours ago) and read 11754 times:
Quoting ZANL188 (Reply 5): Many Boeings have fuses in the engine mounting system that will allow the engine to depart cleanly in certain circumstances...
Theory being that it's better to let the engine go than possibly sustain damage to the aircraft structure.
Quoting Nwarooster (Reply 8): If an aircraft has an engine that becomes so out of balance that it shakes itself to the point that it could cause the failure of the wing, it will break free and fall off the aircraft.
There are what is called fuse pins that hold the engine to the wing or side of an aircraft.
They are designed to break and let the engine fall off the aircraft before any other serious damage could occur to the aircraft. The hydraulic and fuel line automatically seal in the pylon when this happens. old
This is all correct, and may have been what was alluded to in the first post - the engines can separate from the aircraft, however the pilots cannot just flip a switch on the flight deck to jettison the engine at will.
If there is enough vibration and side-to-side movement (the result of a catastrophic engine failure such as throwing a blade, etc) the fuse pins will break and allow the engine to fall away without damaging the aircraft.
This doesn't cause as much of a CG issue as you would think (maybe on the MD-80s and 727s it would be more extreme) and better to fight the CG effects than fight the uncontained engine failure, leading to a wing fire, etc.
Are there any examples of the fuse pins breaking in flight?
MSYPI7185 From United States of America, joined Oct 2007, 690 posts, RR: 0 Reply 12, posted (2 years 5 months 1 week 5 days 19 hours ago) and read 11690 times:
IN short the answer to the question is no!
There have been more than a handful of airliners that have had an engine separate from the aircraft and the aircraft lands safely. You can add Piedmont 732 at ORD to the list and a South African (?) 737 to that list also.
After AA191 crash at ORD many changes were made to help prevent a similar mishap when an engine separtates from a wing.
It all depends on if the engine separates cleanly from the wing without causing structural damage. If it does not all bets are off.
71Zulu From United States of America, joined Aug 2006, 2334 posts, RR: 1 Reply 13, posted (2 years 5 months 1 week 5 days 19 hours ago) and read 11636 times:
ADent From United States of America, joined Dec 2006, 960 posts, RR: 0 Reply 14, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11602 times:
AA191 was due to the pylon failing, not the normal fuse pins. The pylon was damaged by AA using a forklift to install engines instead of GSE. All this was compounded by MDC's not so great design/routing of the hydraulic system.
There was a grouping of reported 727 engines getting whacked by blue ice leaks - and at least one of those was a separation of the engine and completion of the scheduled flight - so not in all cases will the physical loss of an engine be a major event.
There are some JATO setups, but doesn't look like they were jettisoned after takeoff after WWII. For example the B36 was a propeller plane - and it could be equipped with 4 jet engines, but they were not jettisoned.
UAL747DEN From United States of America, joined Dec 2003, 2175 posts, RR: 15 Reply 15, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11570 times:
Quoting ADent (Reply 14): There was a grouping of reported 727 engines getting whacked by blue ice leaks - and at least one of those was a separation of the engine and completion of the scheduled flight - so not in all cases will the physical loss of an engine be a major event.
I don't care why, where, how, what, WHATEVER, if the engine rips off of an airliner it is a major event. I can't think of a more major even the pilot will live to talk about!
ULMFlyer From Brazil, joined Sep 2006, 470 posts, RR: 1 Reply 16, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11517 times:
Quoting UAL747DEN (Reply 15): I don't care why, where, how, what, WHATEVER, if the engine rips off of an airliner it is a major event. I can't think of a more major even the pilot will live to talk about!
That's an easy one. Being hit by a SAM, losing part of the wing, ALL hydraulics, and still landing safely:
Tdscanuck From Canada, joined Jan 2006, 11034 posts, RR: 72 Reply 17, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11503 times:
Quoting UAL747DEN (Reply 15): I don't care why, where, how, what, WHATEVER, if the engine rips off of an airliner it is a major event.
If it rips off, that's almost certainly better than it staying attached. To fuse the engine mount requires enormous amounts of energy (either heat or applied force). Applying that to the engine is bad. Applying it to the wing is much much worse.
Quoting UAL747DEN (Reply 15): I can't think of a more major even the pilot will live to talk about!
JBirdAV8r From United States of America, joined Jun 2001, 4399 posts, RR: 23 Reply 18, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11501 times:
Quoting ADent (Reply 14): There was a grouping of reported 727 engines getting whacked by blue ice leaks - and at least one of those was a separation of the engine and completion of the scheduled flight - so not in all cases will the physical loss of an engine be a major event.
Dl767captain From United States of America, joined Mar 2007, 2539 posts, RR: 0 Reply 19, posted (2 years 5 months 1 week 5 days 18 hours ago) and read 11476 times:
I think it would be interesting as a possibility for something like a water landing or a landing without a landing gear. Being able to jettison the engines would make for a smoother surface for that type of landing. Although you would have to find somewhere for then engines to drop safely
JBirdAV8r From United States of America, joined Jun 2001, 4399 posts, RR: 23 Reply 21, posted (2 years 5 months 1 week 5 days 17 hours ago) and read 11414 times:
Quoting Dl767captain (Reply 19): I think it would be interesting as a possibility for something like a water landing or a landing without a landing gear. Being able to jettison the engines would make for a smoother surface for that type of landing. Although you would have to find somewhere for then engines to drop safely
The cost and hazards involved in installing, maintaining, and just having that system onboard would far outweigh any benefits. As evidenced by AWE1549, airplanes can ditch successfully with wing-mounted engines. I think at least one of the engines (probably both) sheared off in the impact, and all video evidence seems to suggest they didn't cause the aircraft to wheelbarrow into the water.
Engine technology has come a long way since the early days, and the risk of uncontained engine failures (those most responsible for leading to uncontrollable fires) has significantly decreased. The engineering of an engine nacelle is quite remarkable; in fact an engine nacelle will cost a pretty penny.
On a semi-related note the landing gear on many large aircraft have shear pins. I seem to remember driving on Wallace Neel Rd (I think) in CLT and you could drive over the ruts dug by the DC-9 (USA1016) crossing the road on its MLG stubs...
Ual747den From United States of America, joined Dec 2003, 2175 posts, RR: 15 Reply 22, posted (2 years 5 months 1 week 5 days 16 hours ago) and read 11329 times:
Quoting Tdscanuck (Reply 17): If it rips off, that's almost certainly better than it staying attached. To fuse the engine mount requires enormous amounts of energy (either heat or applied force). Applying that to the engine is bad. Applying it to the wing is much much worse.
I agree its much better but still its a pretty big deal when you have an engine break away from the aircraft!
Quoting JBirdAV8r (Reply 18):
I can. A fire on the airplane. I shudder at the thought...
My wife actually had to deal with this as the lone FA on an EMB145. She (and of course the pax) noticed smoke and she called the pilots who told her to go check it out and figure out where the smoke was coming from before they declare an emergency. She replied to the Captain that if he was stupid enough to die on this little POS that was his problem but she was not about to go down with him and if he didn't land this F' ing plane she would come up there and do it for him! Luckily for her there was an entire off duty crew onboard and while she worked to move pax up the pilots were able to take care of the fire.
I flew into where the aircraft landed to see my wife because she was so shaken up. (The airline she was working for bought me a seat on a different airline and put me on the next flight out.) I had dinner that night with both crews onboard and they told me that my wife did her job very well but scared the s**t out of all off them! They didn't think that such a nice small young southern woman could talk like that! The Captain of her flight told me that he has flown with her many times before and he just didnt think that she had it in her to say the things that were said! I say good job and we are all alive happy and well from it
***** I think I got that out before the Ambien stated working if not im sorry
VirginFlyer From New Zealand, joined Sep 2000, 4502 posts, RR: 52 Reply 23, posted (2 years 5 months 1 week 5 days 13 hours ago) and read 11142 times:
A little tangent on fuse pins - they don't always work as advertised. A 767 departing Brisbane a few years back had a turbine disc failure. The engine came to a grinding halt (literally) very promptly (I believe the figure was within one revolution!), with enough force being generated that should have caused it to separate. It didn't, and the force was transmitted into the pylon and wing. The aircraft was on the ground for a number of months for some fairly extensive structural repairs. I never did hear what became of why the fuse pins didn't work as intended. I wonder how many other times such an event has occurred?
V/F
"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh
MD11Engineer From Germany, joined Oct 2003, 12568 posts, RR: 68 Reply 24, posted (2 years 5 months 1 week 5 days 13 hours ago) and read 11103 times:
Quoting Nwarooster (Reply 8): If an aircraft has an engine that becomes so out of balance that it shakes itself to the point that it could cause the failure of the wing, it will break free and fall off the aircraft.
There are what is called fuse pins that hold the engine to the wing or side of an aircraft.
They are designed to break and let the engine fall off the aircraft before any other serious damage could occur to the aircraft. The hydraulic and fuel line automatically seal in the pylon when this happens. old
Nope. You are right about the fuse pins, which are designed to break before the stresses damage the wing, but there are no "automatically sealing" connections on the lines. They will just tear and unless the crew e.g. activates the fire handle. fuel and hydraulic fluid will run out of the torn pipes.
Aesma From France, joined Nov 2009, 3001 posts, RR: 3 Reply 25, posted (2 years 5 months 1 week 5 days 8 hours ago) and read 9617 times:
Quoting Dl767captain (Reply 19): I think it would be interesting as a possibility for something like a water landing or a landing without a landing gear. Being able to jettison the engines would make for a smoother surface for that type of landing. Although you would have to find somewhere for then engines to drop safely
For a water ditching I agree it could be useful, you would probably ditch because of loss of power anyway. However for a landing without wheels, that happens generally because the gear fails, other than that the plane flies well. So the only way to jettison engines that would help would be just before putting the plane down, you're not gonna intentionally turn your flying airliner into a glider. Dropping the engines at the threshold would be the way, and it would be quite dangerous. Imagine if they bounce !
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
C133 From United States of America, joined Jan 2005, 222 posts, RR: 0 Reply 26, posted (2 years 5 months 1 week 5 days 6 hours ago) and read 8811 times:
Another thing, not mentioned, is that the mounts on wing mounted engines are designed so that if the airplane lands gear up, or the gear collapses, the engines should flip up away from the ground. This is to prevent them from digging in and going under the wing, likely rupturing fuel tanks. The engines are heavy items hanging out there and best efforts are made in design to anticipate and minimize what might happen to them.
Fine: Tax for doing wrong. Tax: Fine for doing well.
SEPilot From United States of America, joined Dec 2006, 5908 posts, RR: 39 Reply 27, posted (2 years 5 months 1 week 5 days 6 hours ago) and read 8546 times:
Quoting Mmedford (Reply 2): jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
Think AA-191...
Wrong. Many aircraft have lost engines and landed safely. It was not CG that doomed AA-191; it was a combination of the fact that the leading edge slat control lines were severed causing them to retract and that the pilots had no way of knowing this and the book called for slowing down to minimum control speed (which they did) which caused the left wing to stall. If the pilots had known that the slats were asymmetric and had kept the speed up they would have had little trouble in landing safely. Also, at least one NW 727 had an engine fall off (thanks to a leaking lavatory causing the engine to ingest ice chunks) and landed safely. Several 737's have had engines fall off, and all of them landed safely. A couple of 747's have as well, but a couple have crashed when the departed engine was the inboard one and struck and knocked off the other one as it departed. But CG issues due to an engine departing has NEVER caused a crash.
Quoting UAL747DEN (Reply 15):
I don't care why, where, how, what, WHATEVER, if the engine rips off of an airliner it is a major event. I can't think of a more major even the pilot will live to talk about!
I can think of many things much worse. Seeing as how the engines are DESIGNED to break free under excessive vibration or other stress, it generally is a non-event. It is only a problem when unforeseen events happen, such as AA191, and the two 747's where the departing engine struck the other one on the same wing.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
A333TS From Canada, joined May 2008, 160 posts, RR: 0 Reply 28, posted (2 years 5 months 1 week 5 days 5 hours ago) and read 8160 times:
Am I the only person worried that if the crew will jettison the engine in flight it may do a lot of damage on the ground also.
Can you imagine an engine falling on a populated area from a high altitude? We have seen it before, somewhere in South America a DC10 lost an engine in flight couple of years ago and killed 2 people on the farm. So, I don't think jettisoning an engine is such a good idea. Just my .
SEPilot From United States of America, joined Dec 2006, 5908 posts, RR: 39 Reply 29, posted (2 years 5 months 1 week 5 days 5 hours ago) and read 8009 times:
Quoting A333TS (Reply 28): Am I the only person worried that if the crew will jettison the engine in flight it may do a lot of damage on the ground also.
A single engine still would do less damage that the whole airplane.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
Stratosphere From United States of America, joined Sep 2007, 1522 posts, RR: 4 Reply 30, posted (2 years 5 months 1 week 5 days 4 hours ago) and read 7632 times:
Quoting ADent (Reply 14): There was a grouping of reported 727 engines getting whacked by blue ice leaks - and at least one of those was a separation of the engine and completion of the scheduled flight - so not in all cases will the physical loss of an engine be a major event.
There was two that I can recall that physically lost an engine both were blue ice events. One was an AA 727 over New Mexico I believe and the NW 727 which it fell off over North Florida. Both Engines were recovered.
KennyK From United Kingdom, joined Apr 2005, 473 posts, RR: 0 Reply 31, posted (2 years 5 months 1 week 5 days 4 hours ago) and read 7309 times:
Was there an incident with a 707 in the UK that lost both engines on one wing just after take off, I vaguely remember reading a report written by one of the pilots, so they must have got down OK ?
Lightsaber From United States of America, joined Jan 2005, 8534 posts, RR: 100 Reply 33, posted (2 years 5 months 1 week 5 days 1 hour ago) and read 6063 times:
Quoting MSYPI7185 (Reply 12): IN short the answer to the question is no!
It would be crazy and dangerous to jettison an engine.
Quoting Mmedford (Reply 2): jettison an engine would throw off the CoG numbers by an insane amount...with nasty effects...
Not to mention the FOD.
Quoting JetMech (Reply 7): As others have said, I don't think there ever has been a commercial type with provision to allow the crew to jettison engines. 747's are equipped with fuse pins in the struts however, so an engine could "tear away" if it subjected the strut to immense forces.
There is a shear pin designed to let the engine be 'ripped off' in a ground crash. The idea is that if the wing tilts and the engine 'digs into' the ground (or water) it is better to loose the engine with *known* consequences than to have the airframe pivot around the one engine stuck in the mud (or if there is that much drag in the water). For at that point the plane could cartwheel, rip off a wing, or do something far worse than ripping off an engine if the engine became lodged in the dirt/mud/high drag of water. So the engines do shear off. But under pretty extreme conditions.
Those shear pins are tough! They are usually nickel or stainless bolts precision machined to a precise diameter. They are 'batch tested' to verify their failure modes (shear, axial, etc.).
Magnesium is banned from any modern aircraft's material list due to the fire danger. (I should say any aircraft I've worked on. It is like Tin, just a bad thing to have around aircraft). A burning magnisium pin would burn at 3100C! Plus magnesium is easy to light. That heat would set the aluminum in the wing on fire (plus of course the eventually the wing fuel)! Recall, aluminum is a fuel that is mighty tough to put out once it catches fire.
Tofen From Sweden, joined Feb 2009, 46 posts, RR: 0 Reply 34, posted (2 years 5 months 1 week 5 days ago) and read 5983 times:
Slightly of topic, but does anyone know if it's worse to loose an engine on a plane where they are wingmounted compared to tailmounted?
I can imagine that there will be a much bigger roll tendency if you loose one on a plane with wingmounted engines, since they sit further away from the centerline. I can also imagine there being more sensitive stuff they could damage during the brake, specially on a quad.
On a plane with tailmounted engines i guess you will have more of a CoG issue though, but maybe that's not much of a problem? What about on a VC-10 or IL-62? must be quite bad if you loose a whole pylon on one of those?
What about the number 2 engine on a trijet, are there any way one of those could brake free, or do you just have to pray that you can get the thing on the ground before any damage spreads throughout the tail section?
Lightsaber From United States of America, joined Jan 2005, 8534 posts, RR: 100 Reply 35, posted (2 years 5 months 1 week 5 days ago) and read 5948 times:
Quoting Tofen (Reply 34): Slightly of topic, but does anyone know if it's worse to loose an engine on a plane where they are wingmounted compared to tailmounted?
This is pure opinion on my part, but Center of Gravity issues would be the big difference between losing a wing or tail mounted engine.
The roll issues would be bad, but the control surfaces are large enough to compensate.
Tdscanuck From Canada, joined Jan 2006, 11034 posts, RR: 72 Reply 36, posted (2 years 5 months 1 week 4 days 23 hours ago) and read 5854 times:
Quoting Tofen (Reply 34): Slightly of topic, but does anyone know if it's worse to loose an engine on a plane where they are wingmounted compared to tailmounted?
I don't know for sure, but I'd rather lose a tail-mounted engine. The chances of it getting away cleanly seem much higher.
Quoting Tofen (Reply 34): I can imagine that there will be a much bigger roll tendency if you loose one on a plane with wingmounted engines, since they sit further away from the centerline. I can also imagine there being more sensitive stuff they could damage during the brake, specially on a quad.
The critical roll authority case is considerably worse than losing an engine, so that shouldn't be an issue.
Quoting Tofen (Reply 34): On a plane with tailmounted engines i guess you will have more of a CoG issue though, but maybe that's not much of a problem?
CG forward is stabilizing, so you're not really at a huge loss-of-control risk. It should be one of the design cases for pitch control authority but, even if it's not, landing fast would be enough to hold it.
Quoting Tofen (Reply 34): What about the number 2 engine on a trijet, are there any way one of those could brake free, or do you just have to pray that you can get the thing on the ground before any damage spreads throughout the tail section?
I think the latter...there is some really huge structure carrying the fin loads around the engine and I don't see any way for the engine to cleanly escape that "cage".
JBirdAV8r From United States of America, joined Jun 2001, 4399 posts, RR: 23 Reply 37, posted (2 years 5 months 1 week 4 days 22 hours ago) and read 5776 times:
Quoting Tdscanuck (Reply 36): I don't know for sure, but I'd rather lose a tail-mounted engine. The chances of it getting away cleanly seem much higher.
Phew, not me. I can't imagine a "good" scenario where a DC-10/MD-11 engine departs the tail without seriously endangering the tail itself. A traditional aircraft without a tail has generally lousy chances of making it to the ground in one piece.
Tdscanuck From Canada, joined Jan 2006, 11034 posts, RR: 72 Reply 38, posted (2 years 5 months 1 week 4 days 20 hours ago) and read 5651 times:
Quoting JBirdAV8r (Reply 37): Phew, not me. I can't imagine a "good" scenario where a DC-10/MD-11 engine departs the tail without seriously endangering the tail itself.
I meant tail engine as in MD-80 installation. For the tail engine on a DC-10 type aircraft, I agree with you:
Quoting Tdscanuck (Reply 36): there is some really huge structure carrying the fin loads around the engine and I don't see any way for the engine to cleanly escape that "cage".
Luv2cattlecall From United States of America, joined Sep 2007, 1648 posts, RR: 2 Reply 39, posted (2 years 5 months 1 week 4 days 18 hours ago) and read 5565 times:
Is there a reason why Ethiopian 961's engines didn't cleanly break off, instead turning into huge buckets that flipped the aircraft?
When you have to breaststroke to your connecting flight...it's a crash!
ADent From United States of America, joined Dec 2006, 960 posts, RR: 0 Reply 40, posted (2 years 5 months 1 week 4 days 17 hours ago) and read 5502 times:
Quoting UAL747DEN (Reply 15): I don't care why, where, how, what, WHATEVER, if the engine rips off of an airliner it is a major event. I can't think of a more major even the pilot will live to talk about!
It wasn't major enough to cause a diversion. Of course they did not know until they landed that it actually fell off.
These guys were smart enough to realize an engine was missing and did divert:
VirginFlyer From New Zealand, joined Sep 2000, 4502 posts, RR: 52 Reply 41, posted (2 years 5 months 1 week 4 days 14 hours ago) and read 5344 times:
Quoting Luv2cattlecall (Reply 39): Is there a reason why Ethiopian 961's engines didn't cleanly break off, instead turning into huge buckets that flipped the aircraft?
The wingtip struck rocks and caused the aircraft to cartwheel...
V/F
"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh
DenverDanny From United States of America, joined Sep 2007, 190 posts, RR: 0 Reply 42, posted (2 years 5 months 1 week 4 days 7 hours ago) and read 5041 times:
Quoting Lightsaber (Reply 33): Magnesium is banned from any modern aircraft's material list due to the fire danger. (I should say any aircraft I've worked on. It is like Tin, just a bad thing to have around aircraft).
Magnesium alloys are indeed used in aircraft, perhaps less so than before. I think you shouldn't fixate on a small part of my post, and instead read my whole post. I started talking about vaguely remembering something that I had read, then went and got the book and clarified what I had remembered. I was talking about the 707 that had the engine fall off, as it was designed to do. The 707 does utilize magnesium alloy parts.
As far as magnesium being banned... that's from being carried in the hold of an aircraft, I believe.
Quoting Lightsaber (Reply 33): A burning magnisium pin would burn at 3100C! Plus magnesium is easy to light. That heat would set the aluminum in the wing on fire (plus of course the eventually the wing fuel)! Recall, aluminum is a fuel that is mighty tough to put out once it catches fire.
And keeping a burning engine on the wing would be swell too? Again, read the whole post. I was talking about what I remembered reading, which wasn't exact. You've far extrapolated it.
SEPilot From United States of America, joined Dec 2006, 5908 posts, RR: 39 Reply 43, posted (2 years 5 months 1 week 4 days 2 hours ago) and read 4851 times:
Quoting Tdscanuck (Reply 36): I don't know for sure, but I'd rather lose a tail-mounted engine. The chances of it getting away cleanly seem much higher.
Of all the aircraft that have had engines fall off, the only ones that have crashed have been 2 747's. I don't know of any MD-80's or DC-9's that have had it happen, but 2 727's have and landed safely. So I don't see it as a big issue; the one really dangerous scenario seems to be losing an inboard engine on a quad, because of the chance of taking the other one with it.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
Lightsaber From United States of America, joined Jan 2005, 8534 posts, RR: 100 Reply 44, posted (2 years 5 months 1 week 4 days 1 hour ago) and read 4793 times:
I appreciate the correction. Very interesting tidbit! I didn't know that. I should have read the whole post.
Its before my time.
Quoting DenverDanny (Reply 42): Magnesium alloys are indeed used in aircraft, perhaps less so than before. I think you shouldn't fixate on a small part of my post, and instead read my whole post. I
Ok, below I have a link proving me wrong. Oops. Every project I've worked on in my career has put Magnesium and its alloys, as well as Tin, on the 'not approved' material list. I probably typed too strongly, but we are not allowed to engineer any parts out of magnesium. It has been removed from the material property databases to keep anyone from even being tempted to engineer with it.
Quote: Incendiary use: Magnesium is flammable, burning at a temperature of approximately 2500 K (2200 °C, 4000 °F), and the autoignition temperature of magnesium is approximately 744 K (473 °C, 883 °F) in air. The extremely high temperature at which magnesium burns makes it a handy tool for starting emergency fires during outdoor recreation. Other related uses include flashlight photography, flares, pyrotechnics, fireworks sparklers, and incendiary bombs.
Magnesium die casting metal and its alloys are explosive hazards; they are highly flammable in their pure form when molten or in powder or in ribbon form. Burning or molten magnesium metal reacts violently with water. When working with powdered magnesium, safety glasses with welding eye protection are employed, because the bright white light produced by burning magnesium contains ultraviolet light that can permanently damage the retinas of the eyes.
I didn't know! That is the fun of a.net. Being corrected and learning! Thank you DenverDanny. I didn't realize that on the other side of the pond they were extensively using magnesium today. Even an A320 generator housing.
Hmm... I'll have to research more into magnesium aircraft parts. To see what part of our corporate ban is overcome by events...
Note: I found other links hinting that aircraft piston engine blocks are also out of magnesium, but since I didn't find what specific engines, I just accepted it is used by other groups but banned where I've worked.
Quoting VirginFlyer (Reply 41): The wingtip struck rocks and caused the aircraft to cartwheel...
MSYPI7185 From United States of America, joined Oct 2007, 690 posts, RR: 0 Reply 45, posted (2 years 5 months 1 week 3 days 21 hours ago) and read 4668 times:
Quoting JBirdAV8r (Reply 21): On a semi-related note the landing gear on many large aircraft have shear pins. I seem to remember driving on Wallace Neel Rd (I think) in CLT and you could drive over the ruts dug by the DC-9 (USA1016) crossing the road on its MLG stubs...
I'm not so sure about landing gear with shear pins, I have never herad of them in my 20 years, but that does not mean they do not exist, just I have never herad of them. Generally you want the Landing gear to stay attached to the airframe, as long as possible. When the fuselage hits the ground in an accident that is when bad things really being to happen.
As far as the gouges across the road in CLT, I am not sure what caused them as the aircraft broke in half when it hit a large Oak tree causing the aircraft to break in half sending the tailsection across the road and onto a house that was there. I have to go back and look at my pics of the crash to see if I can tell where the MLG finally ended up. Unfortunately hitting that tree is what killed most if not all of the pax who perished.
Does anyone know with the new runway at CLT does the marker or anything still exist from this accident or has it been relocated? I could be wrong, but IIRC just before I transferred from CLT back to MSY, there was a marker there.
Tdscanuck From Canada, joined Jan 2006, 11034 posts, RR: 72 Reply 46, posted (2 years 5 months 1 week 3 days 20 hours ago) and read 4605 times:
Quoting MSYPI7185 (Reply 45): I'm not so sure about landing gear with shear pins
It's pretty common, at least on Boeing designs.
Quoting MSYPI7185 (Reply 45): Generally you want the Landing gear to stay attached to the airframe, as long as possible.
Only to the extent of not rupturing the wing box (aka fuel tank). Given the choice, you'd rather the landing gear broke away than open up the fuel tank in a crash. For example, the BA 777 landing gear did exactly what it was supposed to do.
Lightsaber From United States of America, joined Jan 2005, 8534 posts, RR: 100 Reply 47, posted (2 years 5 months 1 week 3 days 17 hours ago) and read 4542 times:
Quoting MSYPI7185 (Reply 45): I'm not so sure about landing gear with shear pins,
Quoting Tdscanuck (Reply 46): It's pretty common, at least on Boeing designs.
Nice summary.
We've had a few unplanned 'shear pin' inspections over the years...
SEPilot From United States of America, joined Dec 2006, 5908 posts, RR: 39 Reply 49, posted (2 years 5 months 1 week 3 days 7 hours ago) and read 4329 times:
Quoting MSYPI7185 (Reply 45): Generally you want the Landing gear to stay attached to the airframe, as long as possible. When the fuselage hits the ground in an accident that is when bad things really being to happen.
Not exactly; you want it to absorb as much energy as possible, but not stay attached if it is going to cause something more important (the wing spar, wing box, or fuel tank) to break.
Quoting Tdscanuck (Reply 46): Only to the extent of not rupturing the wing box (aka fuel tank). Given the choice, you'd rather the landing gear broke away than open up the fuel tank in a crash. For example, the BA 777 landing gear did exactly what it was supposed to do.
Exactly. And IMHO this is one of the biggest problems with the DC-10/MD-11. Their design does not have fused landing gear, and since the landing gear is mounted underneath the main spar instead of behind it, when the impact is too severe for the landing gear to absorb it it causes the main spar to break.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
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Magnesium is banned from any modern aircraft's material list due to the fire danger. (I should say any aircraft I've worked on. It is like Tin, just a bad thing to have around aircraft). A burning magnisium pin would burn at 3100C! Plus magnesium is easy to light. That heat would set the aluminum in the wing on fire (plus of course the eventually the wing fuel)! Recall, aluminum is a fuel that is mighty tough to put out once it catches fire. 
I didn't know that. I should have read the whole post.
Even an A320 generator housing. 
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