Saturday, January 23, 2010

When Intuition fails

 Or it can also be called: When Intuition fails Aerodynamics (For Pilots and those aspiring to become pilots).

It failed on that fourth Saturday of May. The night was pitch-black. No clouds, but no moon either. The land below glowed intermittently with lights. It was a 150 miles flight and somewhere in its 148th mile the gremlins of disaster stepped in.

Approach End of the Runway

At first there was a chilling, spine tingling hiccup from the engine. The pilot induced airport lighting glowed in stark linear converging lines of the airport. The faint glow from the street lamps arcing around the airfield and the rest was a large black of nothingness.

Approach End of the Runway at Twilight

The second hiccup from the engine followed the first moments later and the airplane hesitated as the thrust was removed momentarily and it felt like hitting an invisible cloud of resistance. The engine monitors showed little deference to this malady imposed by the firewall forward motor. The propeller blades momentarily lit up from the decreased RPM and the aircraft landing lights. The rabbit lights now flashed the direction to the runway.

The third and the final hiccup came at 600 feet over the ground and ¾ mile from the Runway Touch Down Zone (TDZ). Everything went silent. The hiccups stopped, the propeller continued wind milling in front of the windshield, each blade visible in the reflection, but the drone of the engine was gone. The MP (Manifold Pressure) and the RPM (Revolutions per Minute) needles sank to rest on their pegs.

Aircraft Approach onto the Runway at Night 

He could make it to the runway. The aircraft swooned forward without the thrust. He instinctually pulled on the yoke. The aircraft nose rose in the air and momentarily the wing accommodated the request and the VSI (Vertical Speed Indicator) went from -600 FPM (Feet per Minute) to a 0.

The airspeed indicator unwound from the 120 at cruise now hovered around 70 knots. The Glide Speed was somewhere at 78 knots or so. Somewhere he had recalled that the longest glide was a bit slower than the true Glide Speed, but he was not sure now what that number was so 70 knots felt good. The soul of the needle vibrated within its shell to hold true to the number 70 above the white arc, vacillating wildly as the vestiges of the remaining thrust from the receding momentum of the aircraft and the unchallenged rising drag made the weighty metal of the aircraft yield to the forces of gravity.

He was now over the Rabbit lights and the approach end of the Runway and even the Runway boundary lights were visible.

Rabbit Lights Leading to the Runway Diagram

The altimeter read at 300 feet. He could make it with just a little more pull and nudge of the yoke. The airspeed needle was bouncing between 60 and 65 knots. The aircraft was still flying but sluggishly, slowly the nose felt heavier needing more input decisions from the pilot.

Streams of sweat poured down his back. He felt the cold chill of reason advising the consequence of a botched attempt. If he forced the nose to the ground, he would most certainly crash, destroy the aircraft and the runway lights, cause a big deal with the insurance company and he might not be able to get coverage again, so if he could just tweak the aircraft gently and let the main wheels hit even before the runway, it would be a controlled crash but he would be home free. The silence was deafening and he could hear his pulse in loud waves crashing within his ears. He kept reminding himself to do the first thing, “Aviate.” Fly the plane! But the airfoil aerodynamics were testing the lower limits of the flight envelope and the aluminum aircraft was suddenly turning into all Aluminum.

Aircraft on Approach to Runway

After all he had some 6000 hours of flying behind him and experience had taught him something. The sweat of doubt kept pouring while the chill of fear clutched at him.

The speed decayed to 59 knots and he was 200 feet above ground with three of the last remaining Rabbit lights to go.

Aircraft Accident on Approach

“Damn,” he muttered harshly, “did I switch tanks?” He pressed the Boost Pump Switch to on and with one hand straining on the yoke the other one turned the knob to switch to the opposite tank. The cylinders ignited just as the angle of attack was breeched past the 17-degree limit.

Angle of Attack is between the Airflow and the Wing Angle

Diagram Illustrates the excess Angle of Attack leads to separation of Air from the Wing causing loss of Lift

Aircraft Disaster

The next morning, the sun reluctantly lit the unhappy event of a lost life and bent metal. A family aggrieved into sobs of what it could have been and officials shaking their heads in sorrow over what was avoidable. The right wing tank was half full of fuel while the left one was bone dry. It was a starvation of an unpracticed habit of planning for emergencies – the rites of passage to being an unsafe pilot.
The subtleness of intuition arises from the confines of the soul, garnished with experiential references and it forces the hand of the body’s spontaneity through instinct. Both these richly imbued elements of daily life are governed by the knowledge of the mind. Any amount of experience can, in a flash of a moment if allowed, subjugate to the whims of the former two, leading to disaster.

GA Aircraft accident on final before the runway

Intuition drives the Instincts and the mind with its seat of knowledge governs and moderates the final decision, never the other way around. Practicing Emergency Procedures periodically would have saved the day and another uneventful landing would have been accomplished. Going through a mental checklist of decisions in order of their rightful sequence and no calamity would have struck. Even in moments of panic the oft-practiced sequence would have accomplished the desired outcome.

The devil that makes us match the angle of bank to the slope of the cloud against the attitude Indicator’s display of the Real Reality is the same devil that conspires for bad outcomes when constant practice and proficiency are lacking. Thus acquisition and constant practice of knowledge is the only solution to a safe outcome in aviation and life.

Learn! – Gain knowledge.
Practice! – Gain Instinct.
Live! – Gain Intuition.
Let Intuition and Instincts be guided by Knowledge.

What To Do
Be thoroughly familiar with your airplane and be current in it, or get a check ride.
Pre-plan all aspects of your flight — including weather. Fly your plan.
Use services available — FSS, Weather Bureau, etc.
Pre-flight your airplane thoroughly.
Use your checklists.
Have more than enough fuel for takeoff, the planned trip and adequate reserve.
Be sure your weight loading and C.G. are within limits.
Be sure articles and baggage are secured.
Check freedom of all controls.
Maintain appropriate airspeed in takeoff, climb, descent and landing.
Avoid other aircraft wake turbulence.
Switch fuel tanks before engine starvation occurs.
Practice engine out, emergency landing gear extension and other emergency -- procedures at safe altitude — preferably with a check pilot.
Use caution in mountainous terrain.
Keep your airplane in good mechanical condition.
Stay informed and alert, fly in a sensible manner.

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