TaromA380 From Romania, joined Sep 2005, 332 posts, RR: 0 Posted (7 years 8 months 2 weeks 3 days 11 hours ago) and read 4256 times:
Hello everybody,
As you know, there are many jet fighters that uses small parachutes, located in the tail, to slow the aircraft during landing, thus allowing the landing on shorter runways/clear ground.
I recently found that at the beginning of jetliners era, many of them were using that parachute.
But in our days, there isn't any airliner to use such a "tehnology".
And I wonder WHY ?
The parachute won't be heavy, won't occupy much space, and could be used only in emergency situations, when the runway overrun is inevitable.
Should AF358 had a parachute ...
If people are concerned about safer landings, why not re-introducing the tail parachute ?
MD11Engineer From Germany, joined Oct 2003, 13343 posts, RR: 64 Reply 1, posted (7 years 8 months 2 weeks 3 days 11 hours ago) and read 4251 times:
Because they have to be picked up (they get dropped on leaving the runway), cleaned and repacked all the time. The Caravelle had a braking parachute, but it proved to be too expensive in the long run. On the other hand, economics were never of importance for the military.
TaromA380 From Romania, joined Sep 2005, 332 posts, RR: 0 Reply 2, posted (7 years 8 months 2 weeks 3 days 11 hours ago) and read 4250 times:
I said "used in emergency situations".
If there are problems during landing, what would you preffer: picking up the parachute on the runway or picking up the debris of the airplane & maybe the remains of the victims at the end of the runway ?
LorM From United States of America, joined Jun 2004, 409 posts, RR: 1 Reply 3, posted (7 years 8 months 2 weeks 3 days 10 hours ago) and read 4225 times:
If people are concerned about safer landings, why not re-introducing the tail parachute ?
Quoting TaromA380 (Reply 2): I said "used in emergency situations".
Considering that AF358 didn't declare any emergency situation to ATC prior to landing, no. It should have landed without incident, gone around, or diverted.
MrChips From Canada, joined Mar 2005, 911 posts, RR: 0 Reply 4, posted (7 years 8 months 2 weeks 3 days 10 hours ago) and read 4225 times:
About the parachute not being heavy - you're wrong about that. For an aircraft the size of an A340, you'd be looking at close to half a ton for the parachute...that means the airline would have to take out a minimum of four paying passengers. Over the lifecycle of an aircraft, that amounts to a huge sum of money. Compunding the problem is the cost to maintain the parachutes - you would need large crews to inspect, repair and re-pack these things, both after use and after regular maintenance. And since you propose that the parachute would function as a safety system, the regulators would mandate routine inspections and maintenance on the parachutes
Also, parachutes tend to create problems on landing. If you're landing in a crosswind, it will tend to act like a windsock. And that's the last thing you want with a large transport aircraft.
Finally, even the military designed parachutes out of their aircraft a long time ago. Really, they were designed into aircraft (up until the 1960s in western aircraft) because aircraft brakes were still quite ineffective.
CosmicCruiser From United States of America, joined Feb 2005, 2214 posts, RR: 16 Reply 5, posted (7 years 8 months 2 weeks 3 days 10 hours ago) and read 4216 times:
There's a couple of considerations..
1. "used in an emergency.." Usually by the time one realizes they will leave the runway and will not stop a parachute would do no good since , like reverse, it's use is proportional to speed and
2.most of those older military jets , B-47, etc. didn't have reverse thrust.
Bohica From United States of America, joined Feb 2004, 2411 posts, RR: 0 Reply 6, posted (7 years 8 months 2 weeks 3 days 10 hours ago) and read 4211 times:
Civilian airliners have brakes, thrust reversers, flaps, and spoilers to slow them down. Parachutes are not necessary.
MD11Engineer From Germany, joined Oct 2003, 13343 posts, RR: 64 Reply 7, posted (7 years 8 months 2 weeks 3 days 9 hours ago) and read 4177 times:
Quoting MrChips (Reply 4): About the parachute not being heavy - you're wrong about that. For an aircraft the size of an A340, you'd be looking at close to half a ton for the parachute...that means the airline would have to take out a minimum of four paying passengers. Over the lifecycle of an aircraft, that amounts to a huge sum of money. Compunding the problem is the cost to maintain the parachutes - you would need large crews to inspect, repair and re-pack these things, both after use and after regular maintenance. And since you propose that the parachute would function as a safety system, the regulators would mandate routine inspections and maintenance on the parachutes
Also the tail structure would have to be considerably strengthened to attach such a parachute and transmit the loads to the structure. This means lots of extra weight.
HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58 Reply 8, posted (7 years 8 months 2 weeks 3 days 1 hour ago) and read 4090 times:
Considering the Size of the Parachute required,The Storage space,The Deployment mechanism,the risk of cross wind/entangling,and the recovery.
Lets stick to the good ol reliable Brakes & T/R.
regds
MEL
Lemmy From United States of America, joined Dec 2004, 256 posts, RR: 0 Reply 9, posted (7 years 8 months 2 weeks 2 days 15 hours ago) and read 3996 times:
I think some Learjets made in the 70s came with drag chutes. I would assume that these are only used in emergencies.
Would there be a situation where the addition of a drag chute would be necessary to get the airplane past some regulatory hurdle?
Sovietjet From Bulgaria, joined Mar 2003, 2339 posts, RR: 14 Reply 10, posted (7 years 8 months 2 weeks 2 days 14 hours ago) and read 3976 times:
Also remember that the use of a parachute creates a "jolt" when deployed and everyone flies forward. That is a rough landing which probably would result in some pissed off passengers.
Okie From United States of America, joined Jul 2003, 2378 posts, RR: 3 Reply 12, posted (7 years 8 months 2 weeks 2 days 13 hours ago) and read 3946 times:
The only aircraft that I have seen use a Parachute in the last couple of decades is the F-117.
Let's see Military, Stealth (buried engines no T/R), no high lift devices for slow speed flight, developed before carbon brakes became popular, possibly landing on short airfields, no FAA/JAR requirements, and of course cost is no object.
MrChips From Canada, joined Mar 2005, 911 posts, RR: 0 Reply 15, posted (7 years 8 months 2 weeks 2 days 12 hours ago) and read 3902 times:
Quoting Vsivaries (Reply 13): Maybe large jetliners should be fitted with these parachutes
Again, see above argument - size and weight would be immense. Also, consider this - most accidents with transport aircraft occur at takeoff and landing, and these systems are generally not useful below about 1000' AGL. So, a ballistic recovery parachute would be even more useless than a braking parachute.
The reason why Cirrus installed the CAPS in their aircraft is because there are still pilots out there who decide that it is a good idea to continue flight into IFR or icing conditions when they do not have an instrument rating, or the aircraft is not certified into icing conditions. This gives them an out, so to speak. Also, the parachute allowed Cirrus to demonstrate the aircraft through only one rotation during the spin test. Contrary to popular belief, the Cirrus can recover from a spin with normal control inputs; the parachute is once again just a last resort.
Quoting TaromA380 (Reply 11): They'd preffer that rather than burning alive in the wreckage at the end of the runway, don't you think ?
"only for emergencies"
You must understand that aviation is one huge compromise in motion. For example, if we were to give every passenger an ejection seat, safety would increase immensely, but the aircraft would be so heavy that it would be impossible to make any money with it.
You also have to realize that over 85 years of experience with accidents and safety systems in commercial aviation has been utilized to design aircraft today...I guarantee that designers have looked at emergency braking parachutes and found that there were more reasons NOT to install them than there were reasons to install them.
LongHauler From Canada, joined Mar 2004, 4281 posts, RR: 36 Reply 16, posted (7 years 8 months 2 weeks 2 days 11 hours ago) and read 3888 times:
Quoting TaromA380 (Reply 11): They'd preffer that rather than burning alive in the wreckage at the end of the runway, don't you think ?
"only for emergencies"
Again, by the time you realized you needed it, it would be ineffective. Any "drag" type stopping system, like parachutes, thrust reverse and spoilers become exponentially less effective as the aircraft slows. Conversely, brakes become proportionally more effective as the aircraft slows.
But in the case of AF358 you mention above, if the pilots realized the problems at a time when a parachute would have helped, they also would still have had the option of going around ... all in all, usually a better option.
Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
Bobster2 From , joined Dec 1969, posts, RR: Reply 17, posted (7 years 8 months 2 weeks 2 days 11 hours ago) and read 3875 times:
I think arrester cables would make more sense. The cables would be stored underground and not affect normal runway operations. In case of emergency, pilots could activate them with an electronic signal. No changes would be required to the aircraft. The cables or some sort of barrier would grab the wheels of the plane and bring it to a relatively gentle stop.
I apologize if this is too far off topic. Let me know if I should start a new topic. All I'm trying to say is that there's no excuse to ever have a plane run off the runway and yet it keeps happening: American Airlines in Little Rock, the Southwest Airlines plane that ended up in a gas station, and the recent Air France crash.
LorM From United States of America, joined Jun 2004, 409 posts, RR: 1 Reply 18, posted (7 years 8 months 2 weeks 2 days 10 hours ago) and read 3855 times:
Quoting Bobster2 (Reply 17): I think arrester cables would make more sense. The cables would be stored underground and not affect normal runway operations. In case of emergency, pilots could activate them with an electronic signal. No changes would be required to the aircraft. The cables or some sort of barrier would grab the wheels of the plane and bring it to a relatively gentle stop.
That would require just as much as weight if not more than a parachute system. Structual strengthening of any aircraft would be required in the area of the arresting hook.
Quoting Okie (Reply 12): The only aircraft that I have seen use a Parachute in the last couple of decades is the F-117.
Let's see Military, Stealth (buried engines no T/R), no high lift devices for slow speed flight, developed before carbon brakes became popular, possibly landing on short airfields, no FAA/JAR requirements, and of course cost is no object.
B-52s use brake parachutes. They also have crabbed landing capabilities. There is a landing gear crab dial that has a similar appance to a rudder trim wheel on the center pedestal. All 4 landing bogies can be crabbed in the same direction.
It would be interesting to know what the SOP for the brake chute would be when landing in a crosswind and with wheels crabbed.
USAFHummer From United States of America, joined May 2000, 10685 posts, RR: 54 Reply 19, posted (7 years 8 months 2 weeks 2 days 10 hours ago) and read 3838 times:
Quoting Okie (Reply 12): The only aircraft that I have seen use a Parachute in the last couple of decades is the F-117.
Some foreign F-16 operators have installed them as well...
Greg
Chief A.net college football stadium self-pic guru
Bobster2 From , joined Dec 1969, posts, RR: Reply 20, posted (7 years 8 months 2 weeks 2 days 10 hours ago) and read 3833 times:
Quoting LorM (Reply 18): That would require just as much as weight if not more than a parachute system. Structual strengthening of any aircraft would be required in the area of the arresting hook.
This is an emergency situation where the airplane will certainly be damaged, so is it not better to break it on the runway with fire fighting equipment arriving immediately, rather than letting it bust through the airport fence, roll across a busy street full of traffic, and hit a crowded gas station?
An arresting hook is not needed. The cable would simply pop up in front of the main landing gear after the nose wheel passes over a trigger. The emergency signal from the plane would include data about the size, weight and speed of the plane and the arrester would provide the correct amount of resistance for the situation.
MrChips From Canada, joined Mar 2005, 911 posts, RR: 0 Reply 21, posted (7 years 8 months 2 weeks 2 days 1 hour ago) and read 3754 times:
Quoting Bobster2 (Reply 20):
An arresting hook is not needed. The cable would simply pop up in front of the main landing gear after the nose wheel passes over a trigger. The emergency signal from the plane would include data about the size, weight and speed of the plane and the arrester would provide the correct amount of resistance for the situation.
A novel idea, with a few major flaws. Once again, I will trot out the A340 as an example.
Assume that an A340, weighing approximately 170,000 kg (about 400,000 lb) is travelling at 40 meters per second (roughly 80 knots) at the "barrier". Now we will assume that the barrier is placed 500 metres from the end of the runway (about 1500 feet). Now to stop the aircraft in this distance, you need to apply roughly 270,000 newtons of force (about 2.1 million pounds force) constantly until rest. Now, according to my rough calculations, and including a safety factor of 2 (which isn't enough for this case, as any engineer would say), you would need a cable roughly 35 centimeters (about 14 inches) in diameter to withstand this force. A cable that large would be cost prohibitive, not to mention very heavy - in the neighbourhood of almost 2000 tons.
A cable that large, in fact, would probably rip the landing gear off the aircraft, resulting in an aircraft that now has only marginal ability to control the rest of its landing roll. Now I'm pretty sure that the aircraft would be able to stop with no problems, but remember this - not all runway overruns result in a write-off...this system would guarantee one.
Starlionblue From Hong Kong, joined Feb 2004, 15873 posts, RR: 66 Reply 23, posted (7 years 8 months 2 weeks 1 day 17 hours ago) and read 3667 times:
Quoting Sovietjet (Reply 10): Also remember that the use of a parachute creates a "jolt" when deployed and everyone flies forward. That is a rough landing which probably would result in some pissed off passengers.
Yes and no. With good slider design (a slider is a piece of material that slides along the chute ropes) you can minimize the jolt. But that also slows deployment.
Quoting Bobster2 (Reply 17):
I apologize if this is too far off topic. Let me know if I should start a new topic. All I'm trying to say is that there's no excuse to ever have a plane run off the runway and yet it keeps happening: American Airlines in Little Rock, the Southwest Airlines plane that ended up in a gas station, and the recent Air France crash.
No excuse? If you want to look at it that way. I look at it like this: Pilots are asked to be perfect every single time. That's just impossible. They are human beings controlling machines designed and built and maintained by other human beings. Accidents will happen. Extremely rarely to be sure, but they will happen. That's life.
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 71 Reply 24, posted (7 years 8 months 2 weeks 1 day 16 hours ago) and read 3653 times:
Quoting Bobster2 (Reply 17): American Airlines in Little Rock, the Southwest Airlines plane that ended up in a gas station, and the recent Air France crash.
Pilot error.
Pilot error.
Pilot error.
Before we start spending billions of dollars (no exaggeration at all) on modifying airports and airplanes, let's start modifying airline flight operations departments. I am quite certain that two of those crashes were the very predictable result of a flight department culture. In other words, management error, exacerbated by pilot error.
Land an airplane in a microburst, have your license revoked. Same airline does it twice under one administration - chief pilot or equivalent person has his license revoked and is forbidden for life to work in air transportation.
Some airlines do unsafe things because there are whores out there who will sign off on any procedure the company wants. There are not many of them, but there is at least one at YOUR airline.
Quoting Bobster2 (Reply 17): I think arrester cables would make more sense. The cables would be stored underground and not affect normal runway operations. In case of emergency, pilots could activate them with an electronic signal
You are assuming that a plane with an emergency has electricity. It might not.
Quoting Bobster2 (Reply 17): The cables or some sort of barrier would grab the wheels of the plane and bring it to a relatively gentle stop.
I cannot picture such a device that would not do other damage to the landing gear, possibly break the brake lines, break electric wires to the wheels etc. The landing gear legs are mounted to pivoting trunnions which are mounted to structural members which attach to the spar(s) which form(s) one or more bulkheads for the wet-wing fuel tanks. Some serious engineering is going to be required.
Quoting LorM (Reply 18): B-52s use brake parachutes.
And they are a fifty year old design.
Guys it is really pretty simple. If we can break pilots of landing in microbursts and weed out the ones who will push a bad approach into a catastrophic landing we don't need to spend the billions of dollars modifying the world's airports and airline fleet. The existing system is good enough. We just need to shore up the one weak part of it - humans with a "watch this" attitude toward flying.
The proposals here are, to my mind, rather like having big nets rigged to catch you if the wings fall off. Just not needed at all.
Happiness is not seeing another trite Ste. Maarten photo all week long.
25 Starlionblue: SlamClick seldom loses his good humor on this forum. I don't think he quite did this time either, but it seemed close. Take this as a sign to listen c
26 Bobster2: The cost might not be as high as you think. A primitive arresting system consists of a cable with weights on the end so the airplane drags the weight
27 LeanOfPeak: Easier than cables... http://www.faa.gov/news/news_story.c...e=fact_sheet&year=2005&date=090205
28 SlamClick: That was an interesting topic. We've all seen the gravel traps on mountain passes for trucks that have lost their brakes. That used to be a more comm
29 Bobster2: Actually I don't think it's easy to retrieve a 747 from the arrester bed since the bed is designed to make it very hard for the wheels to turn. The a
30 LorM: We had a bunch of these gravel emergency run offs on Oahu. I've seen a few of them that were used and it looks like they work very well since the ele
31 Bobster2: FAA Advisory Circular "Engineered Materials Arresting Systems (EMAS) for Aircraft Overruns". http://www.faa.gov/arp/pdf/5220-22.pdf NTSB Safety Recomm
32 HaveBlue: LorM, Copied from LeanOfPeaks link a few posts above: EMAS Arrestments To date, there have been three incidents where the technology has worked succes
33 L-188: Even drag chutes are falling out of favor with military aircraft for many reasons, weight being one of the big reasons. costs associated with repackin
34 Starlionblue: LOL! Well no need for them on the carrier. Did the pilots also apply full throttle after touchdown like on the carrier?
35 SlamClick: You know, I have to agree with you. I guess I've been hanging out in non-av too much. I intended to be emphatic and came off as angry. My apologies a
36 Mandala499: I still say the problem is mostly solved when we can figure out what part of CRASH AND BURN pilots are not getting when they still want to land in com
37 Starlionblue: First of all: "STEP AWAY FROM NON-AV!!!" That place drives me nutty Secondly, no need to apologize. We all have our rants. I was just pointing out th
38 Lehpron: This may be off topic, but I didn't want to start a new topic about it. What is the approximate coeff of drag for circular parachute? Does it changed
39 SlamClick: In that case I'd suggest you do start a new thread specifically about that. You are going to want some hits on it very early in order to be able to d
41 Meister808: Thats a load of crap. Management may be making those kinds of calls, but I think the decision there is pretty clear, as it should be for anyone in a
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