Guest Blogs

Petroski on Engineering: Armchair Design & Analysis

Page 1 / 2 Next >
View Comments: Oldest First|Newest First|Threaded View
Page 1/3  >  >>
Beth Stackpole
User Rank
What about design for practical use case?
Beth Stackpole   2/2/2012 6:59:51 AM
Entertaining musing on the give and take of good design. What's the greater takeaway for engineers, though? Don't factor use case into your efforts for fear of legal repercussions? That seems like a cop-out to me. After all, not every flight enjoys the benefit of having mechanically-inclined flight attendents on board.

Dave Palmer
User Rank
reasonably expected misuse
Dave Palmer   2/2/2012 7:19:56 AM
Professor Petroski's final point in this article alludes to the fact that product liability law requires a product to be safe not only in its reasonably expected use, but also any reasonably expected misuse. Engineers are often horrified to learn that the law requires us to take potential misuse of a product into account. Ironically, although we bristle at the idea of other people misusing our products, we also excel at coming up with creative new ways to "use" products others have designed. Some of the new uses which particularly creative engineers find for things may not fall into the "reasonably expected" category.

Ann R. Thryft
User Rank
Re: What about design for practical use case?
Ann R. Thryft   2/2/2012 1:50:10 PM

It's been years, but I remember a flight with, I swear, that same tray table "design," which made it completely unusable when deployed. And that was so obviously the case that I could not understand how the design ever got accepted and the tray table installed, in thousands of planes. I was not so fortunate as Professor Petroski, however, in my flight attendants. This all makes me think less of the legal issues than of the designers/users and use case issues. 

Charles Murray
User Rank
Better than seatback tables
Charles Murray   2/2/2012 7:52:26 PM
The nice thing about the tray tables that Professor Petroski describes is that they are not attached to the seat back. Anything is better than that. If I put my laptop on one of those, the person in front of me glances back over his/her shoulder to let me know I'm bothering them. Worse, when the person in front leans back, the tray table is suddenly so close that there's no room to work.

Ozark Sage
User Rank
Re: That IS a Bad design?
Ozark Sage   2/2/2012 7:56:24 PM
Ann, Beth, Dave & Prof. P.,  I write this as you Professor wrote your article on arm chair design....with toung in cheek.  The story starts with me being the only person, other than crew, left on a plane durind a short layover.  A AL Mechanic arrived and went to work on one of the tables you all described.  He almost instantly recived a loud message over his 2way "you have 5 minutes".  He started to work very delicatly and expertly for the next 10 minutes when he received a VERY loud call "you need to pack it in we have to load." 

Being a company man (I determined by his appearence) he reached down to his tool belt, holstered his Phillips Head screw driver swept his hand dirrectly to the hammer loop, grabbed it , pounded the table into the midseat container, flipped the cover closed and annouced towards the Captain "All fixed sir she's ready to go have a good flight" while exiting the aircraft. 

THIS ALL HAPPENED FASTER THAN THE TIME IT TOOK ME TO WRITE THIS. It sticks in my mind to this day because I am also a Pilot.  

TJ McDermott
User Rank
Re: reasonably expected misuse
TJ McDermott   2/2/2012 9:55:28 PM
I've had another rude awakening this week: no matter how hard I try, how intelligent I may be; there is always one idiot "smarter" than me who will discover the way to damage the machine.  This week, the idiots won.

Arlo Guthrie has a thing or two to teach engineers about "reasonably expected misuse", from his song Alice's Restaurant:


"Kid, I'm going to put you in the cell, I want your
wallet and your belt."  And I said, "Obie, I can understand you wanting my
wallet so I don't have any money to spend in the cell, but what do you
want my belt for?"  And he said, "Kid, we don't want any hangings."  I
said, "Obie, did you think I was going to hang myself for littering?"
Obie said he was making sure, and friends Obie was, cause he took out the
toilet seat so I couldn't hit myself over the head and drown, and he took
out the toilet paper so I couldn't bend the bars roll out the - roll the
toilet paper out the window, slide down the roll and have an escape.


User Rank
Re: What about design for practical use case?
naperlou   2/2/2012 10:38:52 PM
One thing I don't think the airlines or designers really considered is the lifetime of the product in this case.  Is it reasonable to expect something that gets as much use as a tray table to last the lifetime of the plane.  Those are typically flown for many years.  They should have designed them to easily replaced (say during a layover) and refurbished in the shop. 

User Rank
No Room for Improvement
ChasChas   2/3/2012 9:47:46 AM
With everyone so crammed together, there is very little room for improvement - literally.

User Rank
Airplane tables are useful...
SE   2/3/2012 11:58:19 AM
Airplane tables are useful... as mouse pads.  I had access to a bunch of old trays being thrown out.  For black or featureless tables they make very nice mouse pads!  No bending or warping.  Conversation piece too.

As for use on aircraft, they do leave a lot to be desired.  However, there is little choice.  Make a great table and someone will lean on it and bend it.  Make it stronger?  Not only heavier but more tempting to lean on.  Live with it - and carry a pop can tab.

William K.
User Rank
Aircraft tray tables: Armchair analysis.
William K.   2/3/2012 2:35:35 PM
I have come across those tables that pop up from between the seats and have never had any problems with them. Probably being an experienced engineer helps a bit there. I have been on lots of flights where I had to hold my drink so that the bumps would not launch it into my lap, or somebody else's lap. I agree that the ones that fold out of the back of a seat are much nicer, although I have never been able to use a computer on a plane.

If you want a real challenge though, try to utilize the footrest on one of the Amtrack trains. There is a button on the armrest to release it, but in the trains that I have ridden there is nothing to make it move once it is released. The only way we figured out to use the footrest is to grab it with a hand and pull it into position. My guess is that the springs were removed to prevent terrorists from somehow utilizing the footrests for something, or possibly to prevent idiots from doing something really stupid with them.

I really would preferr that our legal system stop rewarding idiots and fools for injuring themselves, and instead, fine them for being so stupid. OF course, then we would have the lawyers seeking customers under some other premise, and that might be worse.

Page 1/3  >  >>
Partner Zone
More Blogs from Guest Blogs
Load dump occurs when a discharged battery is disconnected while the alternator is generating current and other loads remain on the alternator circuit. If left alone, the electrical spikes and transients will be transmitted along the power line, leading to malfunctions in individual electronics/sensors or permanent damage to the vehicle’s electronic system. Bottom line: An uncontrolled load dump threatens the overall safety and reliability of the vehicle.
While risk management sounds like one activity, in order to be conducted effectively, it must be broken down into three sub-components: risk assessment, risk monitoring, and response planning.
While many larger companies are still reluctant to rely on wireless networks to transmit important information in industrial settings, there is an increasing acceptance rate of the newer, more robust wireless options that are now available.
To those who have not stepped into additive manufacturing, get involved as soon as possible. This is for the benefit of your company. When the new innovations come out, you want to be ready to take advantage of them immediately, and that takes knowledge.
Design engineers will feel like kids in a candy store with the Cypress Semiconductor BLE Pioneer Kit. The development kit for low-power sensor-based systems is full of wireless wonder and exploration.
Design News Webinar Series
2/25/2015 11:00 a.m. California / 2:00 p.m. New York
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
3/31/2015 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Mar 30 - Apr3, Getting Hands-On with Cypress’ PSoC
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service