# Aircraft Accidents and the Slide Rule

The slide rule was invented in 1630 by Reverend William Oughtred, sixteen years after logarithms were first used.  For four hundred and forty years the slide rule was the pocket calculator for math and science applications, completing difficult equations from multiplication to Cube roots to Trigonometry.  My shop teacher taught our class how to use the slide rule in the 1970s, just before it became obsolete by today’s computer standards; some middle school teachers still teach the slide rule, even though computers have tried to replace this irreplaceable technology.

Slide rules are dangerous because they open one’s mind to how things work.  Using a slide rule is like teaching a young boy running across a ½ inch-wide beam about gravity or like teaching a child filled with awe about planes how a wing produces lift; it takes all the magic out of what one takes for granted.

Mister Berman (my shop teacher at Sewanhaka High School) taught us the slide rule for a reason: to teach us how the math works.  He foresaw that the calculator would make our lives simpler by doing the difficult math for us, but it would also conceal from us how to find the answers during a blackout or if the batteries died.  In July 1969, Apollo 11 astronaut Buzz Aldrin used a slide rule to double check the descent math during the landing sequence.  Nine months later, the Apollo 13 crew were forced to shut down all necessary power for a time (blackout); although never out of contact with Mission Control, a slide rule would prove invaluable when the power went out and the batteries died; each of the Apollo 13 astronauts knew how to use a slide rule.  From Mercury to Gemini to Apollo, the space programs were born on the slide rule.

Understanding the math is important, not because of power outages and uncharged batteries, but to preserve the ability to do the math; if we don’t understand how we got from A to Z, we sacrifice reasoning; we cannot question; we surrender to another intelligence to do the thinking for us.

Once upon a time, knowing the multiplication tables, from one times one to twelve times twelve and everything in between, were a requirement.  This wasn’t asked of a student, it was expected.  Today students are provided with the multiplication tables attached to the desk – not requested, but expected.  But even this was dumbed down from the students of the 1700s and 1800s, where students at the Elementary school age were expected to do more complicated math problems than long division or multiplication with only a chalkboard to write with.

Reading was the foremost means of entertainment.  No television, i-phones or even radio were available, just firelight and a borrowed book; wealthy members of society actually owned books (plural).  But the point is that information was absorbed by reading the written word, e.g. newspapers, books and published documents.  A video did not play what information you absorbed and audio books did not exist.  We draw closer to the world exemplified in Zager and Evans 1969 song, In the Year 2525, where ‘Everything you think, do or say is in the pill you took today’.

A bit dramatic, possibly cynical?  Perhaps, but think of where we are today in aviation.  Pilots don’t necessarily fly the aircraft anymore; punch a button and the aircraft follows a predefined course; even general aviation aircraft are capable of this.  Manufacturers and air operators are studying the ‘pilot shortage’ problem; the solution is to engineer the pilot out of the cockpit, turn control over to the computers.  Mechanics don’t troubleshoot anymore; they ask the aircraft’s computer, which tells them what to do to resolve the problem.

We are losing the ability to do the math.

No longer do we work through a problem.  We lost track of how to go between A and Z, so accustomed are we to immediate answers, typing (or speaking) the numbers in without bothering about the formula.  Result: a lack of familiarity with the aircraft which can affect how decisions are made and how much time is committed to solving a problem in real time.

Consider Air Midwest 5481, the Beech 1900D that crashed in Charlotte, NC, on January 8, 2003; an airliner that is, for all intents, as close to a general aviation aircraft design as you can get.  Could the pilots’ familiarity with the aircraft have affected how they responded to the emergency?  The aircraft took off with a center-of-gravity too far aft.  In addition, the elevators had been rigged with almost zero nose down authority.  As per the voice recording transcript from National Transportation Safety Board (NTSB) accident report AAR 04/01, from the moment the flight crew realized there was something wrong (they were entering an aerodynamic stall) and tried to push the yokes forward to bring the nose down, about twenty-one precious seconds passed before the crew attempted something else to save the aircraft.

Twenty-one seconds in an emergency is an eternity.

This is, in no way, a criticism of how the flight crew responded; no Monday morning quarterbacking.  However, what they tried by pushing the yokes forward would never have worked.  The yokes’ movements were limited by mechanical stops: metal blocks.  The pilots lacked the physical strength to overcome the metal blocks’ strength; no one alive could have overcome the metal blocks’ strength; two Gold-medal Olympic weightlifters could not have moved the yokes forward.  Both pilots spent twenty-one seconds pushing against an immovable object.

NOTE: There was nothing the aircraft computer could have done to save the flight; not even the most advanced aircraft could have saved the flight.  As we put more and more trust in the computers, this accident was a testament to technology’s limits.  And there are many more testaments in the NTSB accident archives.

But, I digress.  People in the aviation industry must remember this: what doomed Air Midwest 5481 was the loss of twenty-one seconds; the pilots did only what they were capable of doing because both pilots had a limited familiarity of the aircraft’s systems.

The pilots simply could not do the math.

The pilots jumped in the airliner and started the engines; the airliner moved forward.  Push the throttles forward, the airplane went faster.  Pull back on the yokes, the plane went higher.  However, how did the engines work?  When the yokes are pulled back, what occurs to make the elevators go trailing edge up?  Why was the weight distribution in that particular airliner so critical?  Forget the elevators for a second; why did they even depart with the center of gravity so out of limits and why did they not question it?  Why were they incapable doing the math?

A lesson could have been gleaned from the Air Midwest 5481 accident, been part of the recommendations for NTSB accident report AAR 04/01: Require pilots learn basic systems knowledge of the aircraft they fly.  Since many accidents are a result of poor training, a pilot can forego time lost with futile attempts and focus on alternative methods to save the aircraft, at least try.  Learn how to do the math.

Still we continue to allow our youth to ‘not do the math’.  We encourage our youth to substitute figuring out the problem with turning the problem over to the computer.  They are allowed to talk their way out of work, demanding a hand up with no discipline to work it out themselves.

It is time to teach our youth about slide rules; confiscate the calculators and challenge them to work out the math.  If not, the consequences will be more than failing a test, they will fail themselves.

## 2 thoughts on “Aircraft Accidents and the Slide Rule”

1. Prakash says:

You highlighted a very good point: understanding the basics is the key in our professional career.

1. StephenCarbone says:

Thank you, I agree. It’s important we don’t forget the basics.