How long does an aeroplane last ?

[First time Juke]

We had a Piper Arrow recently here that plunged into a lake; three died. It was flown nearly 12 000 hours.

I also recently read about a Twin Otter in USA that rolled over on take off and was destroyed killing the pilot..it was from seventies and similar accident had happened to a Otter previously a control cable was corrupted and snapped ( corrosion ? ).

Is it possible that small crack and worn out pieces go undetected in checks ( like the Quantas 747 oxygen tank ) and cause lotsa damage.

If so why is it. Is maintenance so undervalued or what ?

I have driven a 1970-s built Corvette and streering lost pressure due to old tube/line. How many parts are usually changed in an overhaul of an aeroplane like Piper Arrow.

I think I may have lost a friend in that Arrow accident. The news had not announced the names of the victims yet. I have a bad feeling about this.

Pieces had fallen off from the plane before it plunged nearly vertically into water.

http://www.iltasanomat.fi/uutiset/kotimaa/uutinen.asp?id=1571896

[First time Juke]

Re: How long does an aeroplane last ?

Relief !

I got to talk to the friend who had flown similar flight with same plane a week ago. His class has now 13 students left. Very unfortunate anyhow. He has lost two friends ( and 2 nights sleep ), but luckily was not on that crashflite.

rgds,

Juke

[wyhdah]

Re: How long does an aeroplane last ?

Juke, I believe they left the gust lock in place in that otter crash.

[GeoffS]

Re: How long does an aeroplane last ?

Is it possible that small crack and worn out pieces go undetected in checks...

If so why is it. Is maintenance so undervalued or what ?

... How many parts are usually changed in an overhaul of an aeroplane like Piper Arrow.

Airplanes are some of the most carefully maintained machines around. An annual inspection is required where almost all systems of the plane are examined and brought "to spec". During the "Annual" there are frequently worn parts found and repaired/replaced. Obviously it's possible for something to be overlooked, but A&P mechanics are pretty conscientious.

On top of that, the NTSB investigates almost every airplane accident to determine the "root cause". When a mechanical failure is the at fault, the FAA may issue an "Airworthiness Directive" (AD) that mandates a repair or inspection of other similar airplanes to prevent another accident due to the same cause. This system isn't infallible either, but it does increase the chances that problems that develop over time are found and corrected.

I spend a lot of time in older GA aircraft (just this weekend I was flying in a 30+ year-old Cessna 182), and I don't worry much about mechanical problems (but then maybe I'm just not that smart...)

[Ron101502]

Re: How long does an aeroplane last ?

At Northwest we still fly DC-9s with 75000 hours on them with a cycle limit on the rear pressure bulkead of 96000 cycles. If the airplanes are maintained and inspected properly they will gain weight over the years with structural patches but will be made obsolete by fuel consumption, not airframe age. Of course Douglas built airplanes way tougher than Boeing, just ask any DC-10 structural inspector. The only airliner that may have been tougher built was the Convair 880/990 series where the skins are about double what they would be if it were built today, but then they were the fastest airliners every built besides the Concorde.

Ron

[First time Juke]

Re: How long does an aeroplane last ?

Thanks Geoff S !

I was told this Arrow had wingspar replaced..is that a standard procedure ? How tight are the joints of the old pieces when spar has been replaced..or should also them be replaced if 100% airworthiness is the goal. Is the spar replacement easy to do in an Piper Arrow ?

There are several things that may have happened..smoke in the cockpit due to engine trouble, a forgotten tool in the wrong place...but none of these result in plane leaving pieces behind before impact...unless it is a door...engine had been loud said eye witnesses...recovery attempt from a spin is a cause of loosing lotsa altitude and need of throttle. They had radioed 20 minutes before of changing altitude..lowering it at that stage said my friend who had flown the same school flight a week before.

How would a large bird strike affect...that could make one loose a tailfeathers maybe...a flock of swans or cranes ?

Futile speculation I guess...local NTSB has to collect all pieces first and then study them.


rgds,

Juke

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I just read that there are an accident to an Arrow every 3rd day...147 annually for 18 years...and some known similar cases are also. Lost of the elevator seems most likely by this hour.

[MRussell]

Re: How long does an aeroplane last ?

I just read that there are an accident to an Arrow every 3rd day...147 annually for 18 years...and some known similar cases are also. Lost of the elevator seems most likely by this hour.

Where in the world did you read THAT? Can you provide a link?

[First time Juke]

Re: How long does an aeroplane last ?

Where in the world did you read THAT? Can you provide a link?

US data of PA-28 crashes:

Introduction

Reliability, sturdy construction, and gentle flight characteristics make the Piper Cherokee and Arrow favorites among aircraft owners and the flight training community.

There are currently close to 20,000 PA-28 aircraft on the FAA Registry. During the past eighteen years, there were an average of 147 PA-28 accidents per year, or approximately three per week. In this booklet, the AOPA Air Safety Foundation compares 2,120 PA-28 fixed gear accidents to 5,105 accidents of other light four-place single-engine aircraft during the years 1982-1999. Five hundred nineteen Arrow accidents are compared to 1,140 accidents of comparable aircraft for the same time frame.

check the link here: http://www.aopa.org/asf/publications/piper_cherokee.pdf

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Sorry it was 3 accidents per week and not every third day.

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I also read that cracks have been found on root of the PA-28 elevator mechanism also ballbearings have been corroded or worn out...and they have been changed. Elevator has sorta become loose. Just one specimen...not the accident plane.

Possibly a flutter kinda phenomena has occurred in the elevator..but this is not the local NTSB report ...just some speculaton on the finnish site.

Better check those elevators before it is too late.

[GeoffS]

Re: How long does an aeroplane last ?

I was told this Arrow had wingspar replaced..is that a standard procedure ? How tight are the joints of the old pieces when spar has been replaced..or should also them be replaced if 100% airworthiness is the goal. Is the spar replacement easy to do in an Piper Arrow ?

Wing-spar replacement is a major project, but not unheard of in an older plane.

Futile speculation I guess...local NTSB has to collect all pieces first and then study them.

Very true. If you're interested in getting a feel for the accident rate in aviation, the NTSB has a very nice on-line listing of accident investigations at: http://ntsb.gov/ntsb/query.asp
I regularly check the monthly listing to see what has been going on: http://ntsb.gov/ntsb/month.asp

I just read that there are an accident to an Arrow every 3rd day...147 annually for 18 years...

That statistic makes it sound much worse than it really is. The report (and thanks for the link!), basically says that the PA-28 has about the same accident rate as other 4-place GA aircraft. Also, most of the accidents (66% of them) are minor.

[440_Magnum]

Re: How long does an aeroplane last ?

The only airliner that may have been tougher built was the Convair 880/990 series where the skins are about double what they would be if it were built today, but then they were the fastest airliners every built besides the Concorde.

Ron

As an aside, I was watching an old TV show (early 70s vintage) the other day, and the characters were flying somewhere or other. Of course they used stock footage of airliners so they'd magically take off in a 727, cruise at altitude in a 707, and land in a 747-100, all on a "nonstop" flight. Pretty funny, actually.

But one of the stock shots was clearly a CV-990 rocketing off the runway on 4 trails of incredibly black smoke. Kuchemann carrots clearly visible on the wings and everything. That was worth sitting through all the other gaffes....

The first time I ever saw a CV-990 in the flesh, I was shocked at how tiny it is. Without a frame of reference photos tend to make it look 707/DC-8 sized, but the thing was more like a 4-engine DC-9.

As far as airframe life, my understanding is that its very rare for a passenger airline to ever even come close to "using up" the life of its airplanes. The NW DC-9s mentioned are an unusually long usage, and so were the Delta and Cathay L-1011s. Delta had planned to do the same with their 727 fleet, and had just finished hush-kitting the whole lot when the post-9/11 regs came down and would have required another huge infusion of money on each A/C just for the cockpit doors. So the private aviation and cargo markets got a slug of top condition 727s for bargain prices instead.

At the other extreme you have things like the MD-11, which left front-line usage before the new-airplane smell went away. :-/

[Skyracer]

Re: How long does an aeroplane last ?

I just read that there are an accident to an Arrow every 3rd day...147 annually for 18 years...and some known similar cases are also. Lost of the elevator seems most likely by this hour.

Better check the numbers again Juke; 147 annually is for all Piper PA-28 series aircraft, fixed and retractable gear. The PA-28R is the Arrow (retractable) with a total of 519 accidents over 18 years.

I have about 200 hours in PA-28-140 and PA-28-200R, mostly instructing and flying charter. Can't say that either one had any particularly bad characteristics. Have also done a fair amount of mechanic work on both and, again, cannot say that there were mechanical charcteristics that would make them any worse than other aircraft in the same category.

What the statistics (in your link) do show is that the PA-28's are pretty close to average in comparison to other aircraft in the same category. (Had I been compiling the numbers, there are a few other aircraft I would have included which likely would have brought the numbers even closer together.) The one thing that remains is the cause of the highest number of accidents, the pilot, and that number is little different than the number for all other aircraft.

Losing a friend is not easy, and is even more difficult to understand when lost to something we do and love so much. Aviation, by its very nature carries an above average risk. It is not inherently dangerous; it is, however, terribly unforgiving.

To those who have passed before us .

[Skymonster]

Re: How long does an aeroplane last ?

We had a Piper Arrow recently here that plunged into a lake; three died. It was flown nearly 12 000 hours.

Our (four-share) PA-28 has more hours on it than that - those are quite high hours for any PA-28, but obviously not unheard of. Our airplane now lives in a hangar so doesn't get damp, its well looked after, it gets all the prerequisite inspections and work done promptly. Sure ours has had some work done on it during the years, but I don't get stressed about and I'm not worrying about bits falling off it (or it falling out of the sky). Whilst my heart always goes out to those who lose loved ones, sh*t happens in aviation sometimes. If you want to fly, its something you have to accept. Hours on an airplane are not usually a significant factor - far more serious issues are lack of proper care and maintenance, compliance with ADs, and the skills (or otherwise) of those who operate the airplane.

A