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Boeing 737-400 Safety  
User currently offlinejlivin From United States of America, joined Mar 2010, 2 posts, RR: 0
Posted (4 years 9 months 2 weeks 1 day 11 hours ago) and read 20797 times:

Is it still safe to fly Boeing 737-400 that had been in service for 22 years? I thought after 20 years, they will be discommissioned. Is it because of the economy they are still flying?

69 replies: All unread, showing first 25:
 
User currently offlinealaska737 From United States of America, joined Feb 2006, 1063 posts, RR: 5
Reply 1, posted (4 years 9 months 2 weeks 1 day 11 hours ago) and read 20781 times:

Quoting jlivin (Thread starter):

You realize that there Northwest/Delta DC-9's are still flying, as are 737-200, 727's and heck even WWII era DC-3's and DC-6's. Age of the plane doesn't mean much, having proper or improper maintenance is whats really important. I fly a 1965 Cessna 150E every day and it doesn't phase me at all.


User currently offlineOV735 From Estonia, joined Jan 2004, 920 posts, RR: 3
Reply 2, posted (4 years 9 months 2 weeks 1 day 10 hours ago) and read 20684 times:

The safety is more dependent on the airline you are flying. Some airlines in less-developed/less-controlled countries cut corners in maintenance protocols.

Remember, aircraft are expensive pieces of machinery, that, unlike for example personal road vehicles, receive constant, scheduled, highly-regulated professional maintenance, with each part and detail accounted for and each having its own specific lifespan, after which it will be replaced.


User currently offlineseabosdca From United States of America, joined Sep 2007, 5831 posts, RR: 6
Reply 3, posted (4 years 9 months 2 weeks 1 day 10 hours ago) and read 20668 times:

US carriers routinely fly aircraft for 30 years or more. And the US, especially its mainline carriers, has a phenomenal air safety record in recent years. If the 734 is flying with a US carrier (which means US or AS), then you should step on it with total confidence.

User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 24
Reply 4, posted (4 years 9 months 2 weeks 1 day 10 hours ago) and read 20542 times:

Quoting jlivin (Thread starter):
Is it still safe to fly Boeing 737-400 that had been in service for 22 years?

If it was not safe, AS would have ditched their 734's long ago and wouldn't have any 734F's in their fleet. So yes, they are safe. I would fly on an AS 734 any day!



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlineDaysleeper From UK - England, joined Dec 2009, 873 posts, RR: 1
Reply 5, posted (4 years 9 months 2 weeks 1 day 9 hours ago) and read 20441 times:

I doubt you will get a proper answer on here.

I was making a point in another thread that BOTH the 737 and A320 had great safety records, in doing this I mentioned that statistically you are almost ten times safer on an Airbus than a Boeing (16 Hull loses compared to 144) – the response was to say that it’s not a fair comparison, and that it would only be fair to compare 737NGs to the A320 – Quite what this means I don’t know. And, yes I did take into consideration that there is almost a third more 737's delivered and they have been in service twice aslong - but there isnt a third more hull loss accidetns, or even twice as many - there is almost 10 times as many as I stated.

Also, when the topic of older aircraft has been discussed and the usual response of “good maintenance” is posted, which I agree is a very valid point. But an equally valid point is that maintenance doesn’t include re-wiring a frame – there have been many accidents in which old wiring has been either the cause, or significantly contributed to the cause.

So, like I said, good look getting a straight answer.  Smile

Edit - Not ment to be an "accurate" comparason either, Many of the accidents will not be type related etc.... I haven't gone into each one in detail. Just an interesting statistic thats all.

[Edited 2010-03-09 16:28:28]

User currently offlinewjcandee From United States of America, joined Jun 2000, 5329 posts, RR: 23
Reply 6, posted (4 years 9 months 2 weeks 1 day 9 hours ago) and read 20381 times:

Quoting Daysleeper (Reply 5):
statistically you are almost ten times safer on an Airbus than a Boeing (16 Hull loses compared to 144)

NASA says that fatal accidents are so rare that there is no meaningful statistical analysis to be done from them. It's like statistically-analyzing differences in odds of winning the lottery: in the big picture the win is so rare that you are essentially as likely to win the lottery if you buy a ticket as you are if you do not.


User currently offlineDaysleeper From UK - England, joined Dec 2009, 873 posts, RR: 1
Reply 7, posted (4 years 9 months 2 weeks 1 day 9 hours ago) and read 20343 times:

Quoting wjcandee (Reply 6):
statistical analysis to be done from them. It's like statistically-analyzing differences in odds of winning the lottery: in the big picture the win is so rare that you are essentially as likely to win the lottery if you buy a ticket as you are if you do not.

Hmm, How do you win if you don't buy a ticket?

I think there might be something wrong with NASA's analysis.....


User currently offlineseabosdca From United States of America, joined Sep 2007, 5831 posts, RR: 6
Reply 8, posted (4 years 9 months 2 weeks 1 day 9 hours ago) and read 20258 times:

Quoting Daysleeper (Reply 5):
Quite what this means I don’t know

The biggest reason that a comparison of all 737s to all A320s is misleading is that early 737s, being much older, have ended up in service with more cash-strapped operators in places with poor oversight and safety records. That explains most recent hull losses of early 737s.

Another reason is that flying was much less safe, everywhere, when the 737 was introduced. That explains most early 737 hull losses. Accident rates have plummeted since the late '60s for all types.

And yet a smaller reason is that the A320 has more recent technology than 737 Classics, and, especially, 737-200s.

It's valid to compare A320 and 737NG, as the aircraft have roughly similar levels of technology. It's also valid to compare A320 with all 737s (which would include NG, the majority of Classics, and possibly an isolated very late -200 frame or two) produced since the start of A320 production.

But comparing the types is really meaningless, because with first-tier operators in countries with good oversight, both have had first-rate safety records, to the point that any differences between them are statistically meaningless, particularly in recent years. The big difference is the higher number of 737s operating in less safe parts of the world with less safe operators.

[Edited 2010-03-09 16:58:45]

User currently offlinewjcandee From United States of America, joined Jun 2000, 5329 posts, RR: 23
Reply 9, posted (4 years 9 months 2 weeks 1 day 9 hours ago) and read 20229 times:

Quoting Daysleeper (Reply 7):
Hmm, How do you win if you don't buy a ticket?

That's the point: the odds are so close to zero that buying a ticket it basically irrelevant.


User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9810 posts, RR: 52
Reply 10, posted (4 years 9 months 2 weeks 1 day 8 hours ago) and read 20133 times:

Quoting Daysleeper (Reply 5):
BOTH the 737 and A320 had great safety records, in doing this I mentioned that statistically you are almost ten times safer on an Airbus than a Boeing

All I am going to say is that it is easy to lie with statistics. You can prove anything you want with numbers if you adjust your parameters.

If you actually think that you are 10 times safer flying an A320 than a 737, then that is ok, but you will have a hard time finding a professional with reliability or safety expertise who agrees with you.



If you have never designed an airplane part before, let the real designers do the work!
User currently offline413X3 From United States of America, joined Jul 2008, 1983 posts, RR: 0
Reply 11, posted (4 years 9 months 2 weeks 1 day 8 hours ago) and read 20024 times:

oh man not this again....

User currently offlineafterburner From Indonesia, joined Jun 2005, 1219 posts, RR: 1
Reply 12, posted (4 years 9 months 2 weeks 1 day 8 hours ago) and read 20010 times:

Why did you specifically mention 737-400? How about -300 and -500?

User currently offlinealaska737 From United States of America, joined Feb 2006, 1063 posts, RR: 5
Reply 13, posted (4 years 9 months 2 weeks 1 day 8 hours ago) and read 20001 times:

Quoting Daysleeper (Reply 7):
I think there might be something wrong with NASA's analysis....

Your right, I'm sure your "research" is far greater and more in depth than NASA's


User currently offlinesoon7x7 From , joined Dec 1969, posts, RR:
Reply 14, posted (4 years 9 months 2 weeks 1 day 7 hours ago) and read 19876 times:

If a plane has been flying that long...doesn't that tell you something?   

User currently offlineDashTrash From United States of America, joined Aug 2006, 1563 posts, RR: 2
Reply 15, posted (4 years 9 months 2 weeks 1 day 7 hours ago) and read 19818 times:

No, the airplane isn't safe. I wouldn't fly on it. 

User currently offlineDaysleeper From UK - England, joined Dec 2009, 873 posts, RR: 1
Reply 16, posted (4 years 9 months 2 weeks 1 day 7 hours ago) and read 19777 times:

Quoting alaska737 (Reply 13):

Your right, I'm sure your "research" is far greater and more in depth than NASA's

LOL.  

I was pointing out that the original poster of the Nasa analysis may have made a mistake, or perhaps chosen a bad comparason.

Unless you also believe that someone who doesnt buy a lottery ticket has the same chance of winning as someone that does?


User currently offlineseabosdca From United States of America, joined Sep 2007, 5831 posts, RR: 6
Reply 17, posted (4 years 9 months 2 weeks 1 day 6 hours ago) and read 19720 times:

Quoting Daysleeper (Reply 16):
Unless you also believe that someone who doesnt buy a lottery ticket has the same chance of winning as someone that does?

For all practical purposes, assuming a jackpot lottery, that is correct.


User currently offlinePHLwok From United States of America, joined May 2007, 527 posts, RR: 0
Reply 18, posted (4 years 9 months 2 weeks 1 day 6 hours ago) and read 19631 times:

FWIW, I've been a passenger on over 400 flights over the years on the 734, most on US. I'm still here.

Much like rail travel, flying is still far, far safer than driving.


User currently offlinejlivin From United States of America, joined Mar 2010, 2 posts, RR: 0
Reply 19, posted (4 years 9 months 2 weeks 1 day 5 hours ago) and read 19619 times:

I am not into debating about Airbus and Boeing. I guess, the question is, mechanically, how long 737-400 will last on average. You may tell me one 737-300 has been flying for 30 years. But that does not explain why many of them have been discommissioned way before 30 years limit. You may correct me on this, for example, by showing me the statistics that 70% of the 737-300 had been flying after 25 years etc.....


I noticed some airlines stopped their 737 service once it gets to 20 years limit (like British Airways?) That's why I thought airlines may want to stretch the serving time of their airplanes beyond what's been recommended by Boeing, due to the economic problem. Of course, this is purely speculative, not to offend anybody. In fact, another question, is, does the manufacture give any recommendations regarding the number of years, mileage or the cycles for their airplanes?
Also was the maintainence of the airplanes effected by the economical/financial troubles facing airline industry?


User currently offlineJohnJ From United States of America, joined Jun 2000, 1687 posts, RR: 2
Reply 20, posted (4 years 9 months 2 weeks 1 day 5 hours ago) and read 19597 times:

I flew on a US Airways 737-400 just this morning BDL-CLT. This evening as I type this, I'm alive and well, thank you.

User currently offlineNZ107 From New Zealand, joined Jul 2005, 6456 posts, RR: 38
Reply 21, posted (4 years 9 months 2 weeks 1 day 5 hours ago) and read 19580 times:

Quoting jlivin (Reply 19):
But that does not explain why many of them have been discommissioned way before 30 years limit.

Has it occurred to you that economics and the state of the economy can have an effect on these sorts of things? Less demand means just that - ie your ability to fill planes in the past can only be done so if you reduce tickets. But if you do that, there's a chance you might make a loss. So what's the point in operating an extra plane when you can have sufficient capacity without having to operate that one plane? And what's the point in holding onto a plane which you're not going to use for quite some time? There are planes like some 777s which are about 15 years old and they've been scrapped. Others which are much younger too.

Quoting jlivin (Reply 19):
I noticed some airlines stopped their 737 service once it gets to 20 years limit (like British Airways?)

Why does this matter? Maybe they switched their fleet over to a new Airbus one for reasons such as efficiency?



It's all about the destination AND the journey.
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 22, posted (4 years 9 months 2 weeks 1 day 5 hours ago) and read 19536 times:

Quoting jlivin (Thread starter):
Is it still safe to fly Boeing 737-400 that had been in service for 22 years?

If it's been maintained properly, yes.

Quoting jlivin (Thread starter):
I thought after 20 years, they will be discommissioned

That's a fairly common misconception that stems from the fairly common design goal of a 20 year service life. The way that's actually implemented is to model some hypothetical "average" airline route structure, model it for 20 years, count up the flight hours and flight cycles, and then design to that hour/cycle count. It's actually hours and cycles, not calendar time, that primarily determine the life of the aircraft.

Operators that burn through hours, or cycles, or both faster than the average used in the design will eat the life before 20 years are up. Others that burn slower can last far more than 20 years. This is why there aren't any 707's in commercial service in the US anymore, but essentially identical KC-135's flying all over the place.

Quoting jlivin (Thread starter):
Is it because of the economy they are still flying?

Not really...whether or not an airframe is economical to operate doesn't have anything to do with the state of the economy (other than fuel prices). Bad economies tend to depress demand, which tends to drive older airplanes out faster, not keep them in the fleet.

Quoting Daysleeper (Reply 5):
I was making a point in another thread that BOTH the 737 and A320 had great safety records, in doing this I mentioned that statistically you are almost ten times safer on an Airbus than a Boeing (16 Hull loses compared to 144) – the response was to say that it’s not a fair comparison, and that it would only be fair to compare 737NGs to the A320 – Quite what this means I don’t know.

It means the statistical analysis is only valid if the probability of failure is equal across a particular fleet. The A320 fleet is far more homogeneous than the 737 fleet...the probability of failure is *not* uniform across the 737 fleet, so you can't get meaningful statistical data when you work from the whole fleet.

Quoting Daysleeper (Reply 5):
And, yes I did take into consideration that there is almost a third more 737's delivered and they have been in service twice aslong - but there isnt a third more hull loss accidetns, or even twice as many - there is almost 10 times as many as I stated.

Correct, because an extremely disproportionate number of old 737's are operated in countries with poor oversight and sometimes dodgy carriers.

Quoting Daysleeper (Reply 5):
But an equally valid point is that maintenance doesn’t include re-wiring a frame – there have been many accidents in which old wiring has been either the cause, or significantly contributed to the cause.

Maintenance does include maintaining the wiring (which could drive you to a rewire if you found the right types of problems). Very very few problems are caused by old wiring that's been properly maintained.

Quoting jlivin (Reply 19):
I guess, the question is, mechanically, how long 737-400 will last on average. You may tell me one 737-300 has been flying for 30 years. But that does not explain why many of them have been discommissioned way before 30 years limit.

On average, 20 years. For any individual airframe...anywhere from probably about 14 to over 50.

Tom.


User currently offlineADent From United States of America, joined Dec 2006, 1405 posts, RR: 2
Reply 23, posted (4 years 9 months 2 weeks 1 day 4 hours ago) and read 19438 times:

Quoting jlivin (Reply 19):
That's why I thought airlines may want to stretch the serving time of their airplanes beyond what's been recommended by Boeing, due to the economic problem. Of course, this is purely speculative, not to offend anybody. In fact, another question, is, does the manufacture give any recommendations regarding the number of years, mileage or the cycles for their airplanes?

Typically you get rid of your older planes in a downturn. They have no (or cheap) leases to break when you park them, and they are the least efficient, and require some extra maintenance.

Now you may also stop deliveries of new planes, but most airlines don't need the capacity during a downturn.

After the Aloha convertible 737 incident, there was a large effort by both the manufactures and FAA to improve the safety on really old aircraft. There are hard limits set by the FAA, but they can be extended with support of the manufacturer and/or lots of work.

Quote:
Quoting Ncelhr from How Has The DC-9 Lasted This Long? (by C5LOAD Jan 15 2010 in Civil Aviation)
A319/A320/A321 - 48,000 cycles
B727 - 60,000 cycles
B737 - 75,000 cycles
DC9 - 100,000 cycles
MD80 - 50,000 cycles

Now in fact those figures are not absolutely static.
Indeed, the estimated service goal (total No. of estimated flight cycles) may be extended with time. This is done by a regular review of engineering reports re: structural repairs in each aircraft type, and if in some conditions, the estimated service goal is extended.

I have read a report a couple of years ago, about the DC9 service life being extended to more than 100K. Can't remember if it was 110K or 120K, but it was a number which really got me to raise my eyebrow and openly say "well done, Douglas engineers!"

.

Quoting jlivin (Reply 19):
Also was the maintainence of the airplanes effected by the economical/financial troubles facing airline industry?

Everyone wants to say no - but I would have to think there is a tiny drop. What may go up significantly is time on the ground since spare parts inventories may be cut.

I think the worse case for maintenance is the massive outsourcing, sometimes to the lowest bidder.


User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 24
Reply 24, posted (4 years 9 months 2 weeks 1 day 3 hours ago) and read 19338 times:

Quoting jlivin (Reply 19):
how long 737-400 will last on average.

Well, I don't know..... AS got their first 734 back in 1992, IIRC, N754AS I believe. That is 18 years ago and AS still flies the 734 as stated earlier.



A Safe Flight Begins With Quality Maintenance On The Ground.
25 airbuseric : Not correct, since BA still operates a rather large fleet of B737-400's from their LGW base, and will be for the coming years.
26 ABQ747 : I flew a Qantas 737-400 last year from BNE to TSV. It got me to my destination without incident......
27 cchan : Frankly, I wouldn't mind going on a 737-300/400/500/600/700/800/900, but I would hesitate about a 737-200, especially in Africa, they can be flying de
28 afterburner : A properly maintained -200 is safer than poorly maintained classics or NGs. In Indonesia, there's an airline, whose fleet is dominated by -200, that
29 cchan : I don't doubt this as a fact, but without detailed research into the airline before buying a ticket, companies which operate a -200 do not give good
30 BMI727 : The difference is really not that big. Perhaps a better comparison would be which lottery do you enter. Do your chances of winning the lottery (dying
31 cchan : This depends on which parts of the world you are in. If you are talking about flying in North America, Europe and Oceania, most airlines are to reaso
32 joffie : Age means nothing. I could operate a car that is 30 years old, no problem, as long as its serviced properly. Airlines, just like car owners retire car
33 MSYPI7185 : There also have been accidents where newer wiring fails also. Swiss Air comes to mind. Not really, the number of cycles would have more to do with it
34 Raffik : British Airways operate a large fleet of 737s from Gatwick . . .They are all perfectly safe and do a great job for the airline
35 Bennett123 : Having flown a variety of B737 Classics over the last 10 years, I would no problem in doing so again. 16/08/2000 BMI LHR BRU 21/08/2000 Virgin Express
36 brilondon : You are right. Nobody on here knows more then you about this topic. I have lived in Hawaii for about four years now and the 737's of Aloha Cargo shou
37 BeechNut : With all due respect, your C150, and my '79 Beech Sundowner, aren't pressurized and don't operate in the flight levels with maximum pressure differen
38 rbgso : I'd go ahead and buy the ticket. In the event you survive the trip, you can tell your grandchildren how you cheated death one day by flying a 734. Ser
39 LHR380 : I flew in a 744 the other day, built in 89, and did not feel scared at all, why would I. If the plane was too old or unsafe the airline would have tak
40 413X3 : I think some carriers in the 3rd world including in Indonesia have shown just how dangerous even a next gen 737 can be. It's all about training regul
41 mariner63 : Especially with your answer he won't get a proper answer. Do you realize though that the 737 has been flying for about twice as long as the A320? The
42 MCOflyer : I have flown on so many 737's I would not know where to begin. My routes were: MCO-PHL All MCO-PIT Operated MCO-CLT With PHL-MCO 733 or PIT-MCO 734 Eq
43 Dazed767 : Flew on a 1969 DC-9-40 yesterday and I'm still here...a bit deaf, but alive.
44 Post contains images spudsmac : BTW, you have your answer now. This thread should be archived.
45 SEPilot : I have to argue this. Someone eventually does win the lottery; but whoever did did buy a ticket. To the non mathematically inclined 1/1,000,000,000 m
46 wjcandee : I think that a statistician would be the guy who tells you that your odds of winning the Powerball jackpot are indistinguishable if you buy a ticket
47 EA CO AS : What a ridiculous observation! By your logic, statistically you are also: - More likely to die of a nuclear explosion in Japan than any other country
48 SEPilot : If you do not buy a ticket, you will assuredly never win. Someone who does buy a ticket will win, however. That is the difference. Also, if you inver
49 Bennett123 : iirc, you are in greater danger when driving to the airport than when flying a B737 or A320. This whole thread is very silly. If you have any serious
50 ScottB : The original post of the NASA analysis isn't as inherently flawed as yours. To make a meaningful comparison of "safety records," one would need to, a
51 Woosie : [quote = alaska737, respuesta = 1] I am a professional reliability and design safety engineer, and heartily agree with you. Granted, I work for Boeing
52 7673mech : M There is no 20 year limit. I has to do with economics. Flight hours and more importantly cycles. The maintenance that has been performed and that wi
53 brilondon : This topic has run its course and I ask the moderators to archive it and I wonder why it has gotten this far with such erroneous and non factual infor
54 Post contains images FX1816 : That would be amazing given that the oldest 737-300 is 1984 vintage, so 26 years old. FX1816
55 BMI727 : But the only way to really not buy a ticket is to just not travel. Air travel is the lottery with the lowest odds of "winning," and the odds of doing
56 acabgd : Or, as one famous Serbian sports reporter once said: "Statistics are like bikinis. Showing a lot, without divulging anything"...
57 Post contains images soon7x7 : The 747 is a good example of aircraft stamina...they were designed for a service life of a bout 68,000 hours. Flight cycles determine wear and tear an
58 Daysleeper : Well this thread when a predictable way.... What I originally posted was very “tongue in cheek” The real point I wanted to make was that it is imp
59 Daysleeper : I missed this one... Sorry. TWA800, United 811, SAS 111 - Those are just off the top of my head. I'm sure there are many more.
60 Post contains images EA CO AS : Thank you for admitting your statistical analysis was misleading at best. I'd say calling into question the safety of ANY aircraft is controversial w
61 Post contains links and images Daysleeper : I don't wish to be ignorant - but I don't see any point in discussing this, nothing constructive can come from it. It's far more interesting to talk
62 seabosdca : The wiring involved in SR 111 was not aging; it was nearly brand new. In the course of looking at this I've seen a few other minor incidents involvin
63 Daysleeper : The op didn't say old, said wiring. And who/what opened the door? The locking mechanism was a backup system which wasn't upto the job - The initial f
64 seabosdca : The reason it became an issue in the first place is because you were insisting, on very flimsy evidence, that aging wiring makes aircraft less safe.
65 Daysleeper : Yes, and I stand by my point. There have been accidents directly attributed to old wiring. When I get chance i'm going to look for more examples, as
66 SEPilot : And you will find many people who say that was a smokescreen, and in fact it was hit by a missile. I am unsure about this; but I do find the official
67 Post contains images SXDFC : No matter what plane your on, what car your driving in, what sidewalk you walk on, when your time is up- ITS UP!
68 BMI727 : I thought that the explanation was that a current arced from larger wires onto the smaller wires that led to the fuel gauge.
69 tdscanuck : OK...so what was the theory? Calling the safety of any airliner into question using bad analysis is the problem...you would have got the same reactio
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