Minimum Time Between Failure?

It is not. It is defined as "Mean Time Between Failure" which also means, there will be an article which never fails and another article which fails after an extremely short lifespan.

G-damn engineers on my side want to hold a supplier financially accountable to determine root cause of an early failure and are stubbornly unwilling to accept the definition of "mean average."

Oh how I despise the "holier than thou" engineer(s).

Because engineers are some of the dumbest smart people you will ever meet.

As an engineering technician in manufacturing since I retired from the Navy, they are the bane of my job. My typical conversation with them starts with "why did you change that? " replied with "because your original design doesn’t work." This usually leads to 4-5 shifts of downtime until they figure out that the original design doesn’t work.

Also retired Navy Aviation here.

Want to really get under their skin? After listening to the engineers explain the fielded system and why it works, casually state, "engineers only tell us how it's supposed to work, technicians tell us how is DOES work."

Watch their heads explode with your blasphemy.

(edited to make sense)

This message has been edited. Last edited by: LS1 GTO,

As a previous eng mgr; I will say, 20% of them are smart, 20% are mechanically inclined, and the rest… like talking to a box of rocks- and as bright.

They're the same people that say, "for all intensive purposes"?

quote:

Originally posted by ccwguy:
They're the same people that say, "for all intensive purposes"?

For all intensive porpoises.

[Manufacturing Engineering Manager has entered the chat.]

Ooh! Ooh! An engineer-bashing thread! I love it!

My daughter is a chemical engineer (the other a biomedical. She is very fluent in speaking and writing English, and has made a career of communicating between engineers and production staff. Both engineering and communication skills are rare in engineers in my experience.

I spent many years dealing with Electrical Engineers . Some were outstanding . Some of them should have chosen another profession .

My electrical engineer friend’s favorite saying: At some point you have to shoot the engineer and just build the damn thing!
Talking to engineers is quite often like talking to a wall.

Okay, that felt good.

I spent 40+ years working on cars cursing engineers and designers, aided and abetted by the stylists and bean counters.







GM and Ford trucks have an electronic module that controls the electric fuel pump output. They couldn't put it at least under the hood so it's out of the weather. Oh, no. They put it on the frame under the bed. I had to replace - and sublet the programming - several that were corroded away.

Uncounted other examples exist. These people need to spend at least two years in a repair shop before being turned loose to engineer and design stuff. Or hit upside the head with a clue-by-four.

But it looked good in CAD.

I'm an engineer and what you all are saying is true. Biggest problem with a lot of engineers is arrogance and a lack of common sense.

As a career machinist, I've lived it.

I've always believed engineers need to spend a few years in the shop.

quote:

Originally posted by LS1 GTO:
engineers on my side want to hold a supplier financially accountable to determine root cause of an early failure

Sometimes, early failure is just random (where MTBF meets statistics)....other times, it's a dead canary where you didn't know there was a coal mine. It can occasionally be useful to know what you're seeing.

Years as a purchasing agent, one year as QA for a defense contractor, degree in mechanical engineering, years in marketing/business dev/product management so I can see multiple aspects. Still, I'm not sure what your complaint is?

quote:

Originally posted by joel9507:

quote:

Originally posted by LS1 GTO:
engineers on my side want to hold a supplier financially accountable to determine root cause of an early failure

Sometimes, early failure is just random (where MTBF meets statistics)....other times, it's a dead canary where you didn't know there was a coal mine. It can occasionally be useful to know what you're seeing.

Years as a purchasing agent, one year as QA for a defense contractor, degree in mechanical engineering, years in marketing/business dev/product management so I can see multiple aspects. Still, I'm not sure what your complaint is?

MTBF and Root Cause investigations have defined parameters set by the USG / DoD. When and article fails early but does not meet the parameter for Root Cause, the Buyer funds the analysis, the Supplier should not be expected to absorb the costs.

The same might also follow that when an article (complex processing and imaging electronics (SAR, EO/IR, and other intelligence gathering payload) in this case) does not fail after exceeding 10x the MTBF without any failure or degradation of quality, the same logic could be applied to require the Supplier to absorb costs to determine why the article has performed so well to its design. (ie., determining what went right)

^^ Thanks, that clarifies. Sounds like it's in the realm where there are defined roles.

Hoping it proves to be unexceptional.

In this specific situation, the unit failed after apprx. 1,000 flight hours. MTBF is 2,600-ish hours.

And although MTBF is calculated and set in the specs, moat all other of these payloads are exceeding 3,000 hours between initsl install and failure.

The comments and videos shared by egregore got me thinking a bit. I think it's mostly relative.

That oil draining onto the electric power steering unit is very stupid. I have worked on vehicles (Toyota, I think) that had similar scenarios, but utilized a built-in drip tray with a little drain spout, so the oil would not coat the part beneath the drain. That may be the "shield" the guy in the video mentions, and definitely should be there. However, the technician could use a piece of a plastic sheet draped over that PS unit, if he was really concerned about the oil contacting it.

The batteries in inconvenient locations is relative to the compromises made in positioning them elsewhere or creating easier access. It's also relative to the typical lifespan of the battery and the rate of pay for the work required to replace them. I know many shops operate on a flat rate system. If the rate for that service isn't fair, that's no fault of an engineer. When it comes to design compromises, things like ease of access require compromises in overall size and weight of the vehicle: both undesirable.

I replaced the headlight assemblies in my wife's '08 Lexus is250 a couple years ago. I had to disassemble much more of the front end of the vehicle than I thought should have been necessary. I have replaced spark plugs in a BMW V12, which required much more disassembly of the the top of the engine assembly than should be necessary. I don't know what the service intervals on these items are supposed to be, and I don't know how a flat rate system would value these processes.

I love working on my '95 Wrangler, but it obviously lacks much of what my wife's is250 has, and it's not "better engineered".

The Ferrari F355 (I think) requires the engine be taken completely out to perform virtually every service, to include regular preventative maintenance items. Few would argue that the vehicle is poorly engineered.

I am not eager to play white knight for engineers, but I think much of this stuff is more multi-faceted than our impulse reactions imply.

quote:

Originally posted by selogic:
I spent many years dealing with Electrical Engineers . Some were outstanding . Some of them should have chosen another profession .

This is 100% accurate.

Sadly I find many (but not all) of the younger engineers do not have a good grasp on the basics that should be gained in college. Things like physics and other basic sciences.

They solve problems not from experience, thought, or experimentation, but rather just by Googling for the answer.

quote:

Originally posted by vthoky:
[Manufacturing Engineering Manager has entered the chat.]

Ooh! Ooh! An engineer-bashing thread! I love it!

Who doesn’t?