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Accident case study: VFR into IMC - Lessons from the '178 Seconds to Live' spatial disorientation study

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains By Dan Sobczak
October 2020

Editor's note: This content does not constitute flight instruction. Consult a certified flight instructor in your area for proper flight instruction.



You may have first seen it on an old piece of paper posted on a bulletin board at your flying club, or at a local flight school.

Get instrument rated to avoid the potential dangers of accidentally flying VFR into IMC. Composite photo by Dan Sobczak.

Get instrument rated to avoid the potential dangers of accidentally flying VFR into IMC. Composite photo by Dan Sobczak.


The '178 Seconds to Live' story tells you how many seconds you have left to live if you continue flying VFR into IMC conditions, and you're not trained to handle such a scenario. It's been around for quite a few years now.

Converting 178 seconds to minutes equals about 3 minutes of time you have, after inadvertent VFR flight into IMC, to make a decision to turn around before you get in too deep, lose your situational awareness, and succumb to spatial disorientation, perhaps ending up as yet another CFIT statistic -- Controlled Flight Into Terrain -- or maybe another LOC accident -- Loss Of Control -- in the NTSB records.


This 178 second countdown clock gives you a feel for the amount of time you have -- just under 3 minutes worth -- before an inadvertent flight from VFR into IMC might end in disaster for the untrained pilot, according to the '178 Seconds to Live' story. Countdown timer code snippet courtesy of css-tricks.com.


The '178 Seconds to Live' story goes as follows:

If you are ever tempted to take off in marginal weather and have no instrument training, read this article first before you go.

How long can a pilot who has no instrument training expect to live after he flies into bad weather and loses visual contact? Researchers at the University of Illinois found the answer to this question. Twenty student "guinea pigs" flew into simulated instrument weather, and all went into the graveyard spirals or roller coasters. The outcome differed in only one respect: the time it took to lose control. The interval ranged from 480 seconds to 20 seconds. The average time was 178 seconds – two seconds short of three minutes.

Here is the fatal scenario

The sky is overcast and the visibility poor. That reported 5-mile visibility looks more like two, and you can't judge the height of the overcast. Your altimeter says you are at 1500, but your map tells you there is local terrain as high as 1200 feet. There might even be a tower nearby because you are not sure just how far off course you are. But you have flown into worse weather than this, so you press on.

You find yourself unconsciously easing back just a bid on the controls to clear those none-too-imaginary towers. With no warning you are in the soup! You fight the feeling in your stomach. You swallow, only to find your mouth dry. Now you realize you should have waited for better weather. The appointment was important - but not that important.

Somewhere a voice is saying "You've had it - it's all over!"

You now have 178 seconds to live. Your aircraft feels on an even keel, but your compass turns slowly. You push a little rudder and add a little pressure on the controls to stop the turn, but this feels unnatural and you return the controls to their original position. This feels better, but your compass is now turning a little faster and your airspeed is increasing slightly. You scan your instrument panel for help, but what you see is just a bad spot. You will break out in a few minutes. (But you don't have a few minutes left.)

You now have 100 seconds to live. You glance at your altimeter and are shocked to see it unwinding. You are already down to 1200 feet. Instinctively, you pull back on the controls, but the altimeter still unwinds. The engine is into the red, and the airspeed, nearly so.

You have 45 seconds to live. Now you're sweating and shaking. There must be something wrong with the controls; pulling back only moves that airspeed indicator further into the red. You can here the wind tearing at the aircraft.

You have 10 seconds to live. Suddenly, you see the ground. The trees rush up at you. You can see the horizon if you turn your head far enough, but it's at an unusual angle -- you're almost inverted.

You open your mouth to scream, but -- you have no seconds left!"

Source: FAA.gov


178 Seconds Origins


A few articles have been written over the years as to the '178 seconds' source and authenticity.

This article, '178 Seconds Dissected', reviews the origin of the 178 seconds story, which was actually a study by the University of Illinois at Urbana in 1954, funded by the AOPA Foundation, to help identify solutions that might help pilots avoid VFR into IMC accidents.

You can read the full published study from 1954 -- entitled "180 Degree Turn Experiment" -- here.

In 2016, FlightSafetyAustralia.com posted this article, '178 seconds to live - VFR into IMC', to help illustrate some of the dangers of continued VFR flight into IMC.


Lessons learned from VFR into IMC flights


As David Rowland wrote in 2017 on avweb.com about surviving VFR into IMC, VFR into IMC accidents have a high fatality rate. Reading through NTSB reports only confirms the VFR into IMC statistics.

Rowland wrote about why they happen, and reviewed some strategies for surviving VFR into IMC based on research into reports from pilots who successfully handled the challenge.

While we strongly suggest you read Rowland's avweb.comfull article here, we'd like to highlight a few important points he mentions in his article. The quoted excerpts below are from his article.

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

Common factors that lead to VFR into IMC: "Thousands have tried to dissect the reasons for decisions pilots have made over the decades to start or continue a VFR flight despite obvious warning signs that the weather may not be conducive to doing so."

"Get-there-itis is one of the most commonly cited. The 2007 NASA GA Weather Encounters study cited a litany of others including time pressure, equipment problems, distraction by passenger or flight crew, fatigue, illness, management pressure, ill patient, insufficient training, insufficient preparation and lack of familiarity with onboard navigation equipment. Awareness of the factors involved in deciding to continue VFR into IMC may help pilots avoid doing so in the future."


Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

The problem of 'Decision framing': "Decision framing is a bias in which people react differently to a particular choice depending upon how the outcome of the choice is presented."

"In the article, it was put forth that if a pilot framed the decision to divert as a loss (e.g. wasted time, money, missed opportunity), the pilot might be risk-seeking and choose to continue the flight. If, on the other hand, a pilot frames the decision to divert as a gain (e.g. avoiding loss of lives), the pilot would be more likely to divert."

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

The problem of 'Plan continuation bias': "A bias towards continuing with the original plan even though there are indications that the situation is deteriorating. Pilots are goal oriented - once they start toward a destination, they do all they can to keep going toward it, even when doing so is no longer in their best interest."

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

The problem of perceiving visibility: "The ability to accurately perceive visibility varies from individual to individual. In a study published in 2000 by D. Weigmann and J. Goh done at the University of Illinois, 32 subjects were put into a simulator and embarked on a VFR flight with an estimated in route flight time of one hour. During the flight, visibility was gradually reduced from 5 miles to 2 miles. 22 of the 32 subjects continued on after the visibility dropped below the three-mile VFR minimum for operations in the airspace in which they were flying."

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

Transitioning quickly - switching your visual scanning: "The switch from visual flight to instrument flight requires that the pilot switch from peripheral vision to central vision... the conflicting sensations from the vestibular system almost always causes some degree confusion, especially when the need to make the switch is unexpected."

Flight Chain App

The only aviation accident app that helps you see and understand the accident chain from NTSB reports.

In essence, this advice to "pick up your visual scanning" seems to apply. In other words, switch your scanning technique, and do so quickly, so you're taking in all the pertinent information you need to make correct decisions and actions.

Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains

Stay in the fight: "It's essential that the pilot stay in the fight -- remain determined to keep up the instrument scan and keep the airplane under control."

Staying in the fight and not giving in to the hazardous attitude of Resignation will help you break the chain that is developing when an inadvertent VFR into IMC flight is in progress.

PS: In the amount of time it took you to read this blog post, it's likely that 178 seconds has nearly -- or already -- expired. Scroll back up to see where the 178-second countdown timer is in its countdown.

Stay sharp!
The Flight Chain App team




Flight Chain App - NTSB Aviation Accident Reports - Helping pilots learn from accident chains Dan Sobczak is the founder of www.FlightChainApp.com, a mobile app that helps pilots learn from accident chains by making NTSB reports more convenient and easier to digest. Dan received his private pilot certificate in 2003.


Flight Chain App and its companion blog www.AheadOfThePowerCurve.com are committed to reducing general aviation accidents, helping improve aviation safety, and growing the pilot population.


Ahead Of The Power Curve
Blog Archives

2020


November 2020:
Pilot proficiency check: Staying mentally proficient when grounded
October 2020:
Accident case study: VFR into IMC - Lessons from the '178 seconds to live' spatial disorientation study
September 2020:
An 'almost' accident case study: Air Canada Flight 759 near miss
August 2020:
Accident case study: Cory Robin's crash into a river in Ohio
July 2020:
Accident case study: Air Florida Flight 90 - Crash into the Potomac River
June 2020:
Accident case study: Eastern Air Lines Flight 401 - The story of the light bulb
May 2020:
Accident case study: Air France Flight 447 crash into the Atlantic Ocean
April 2020:
NTSB report released detailing Roy Halladay accident; was there faulty ADM involved?
March 2020:
Keeping your real-world flying skills sharp with a home-based flight simulator
February 2020:
NTSB preliminary report: Thoughts on the helicopter accident involving Kobe Bryant
January 2020:
Aviate, navigate, communicate -- in that order -- even if your Cessna 172 is missing a wing



2019


December 2019:
Quick reactions and knowing emergency procedures by memory lead this pilot to a successful engine out landing
November 2019:
Flying the 'Impossible Turn' during an engine failure after takeoff: when is it actually a 'Possible Turn'?
October 2019:
Using a 'Defined Minimum Maneuvering Speed' to help prevent the most common fatal general aviation accidents
September 2019:
Three strikes and you're out: A good rule of thumb to avoid being the star of your own 'never again' story
August 2019:
A real pilot story that ended in a stall spin accident, and 14 flight planning checklist tips every pilot should know
July 2019:
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June 2019:
Getting the most out of scenario-based flight training and a realistic home flight simulator
May 2019:
Quiz yourself with questions based on actual NTSB accident reports
April 2019:
Study: ADS-B In is helping reduce the general aviation accident rate
March 2019:
Bird strike prevention: It's possible, provided pilots have the right tool
February 2019:
A P-51 Mustang's engine-out off-airport landing every pilot can learn from
January 2019:
Learning by repetition: a good pilot is always learning (and re-learning)



2018


December 2018:
Your aviation goals and New Year's resolutions for flying in 2019
November 2018:
Celebrate Flight Chain App's first anniversary with... easter eggs?
October 2018:
Flight Chain App releases new NTSB accident trends feature in latest update
September 2018:
Aviation books to read that will help you fly safe
August 2018:
Accident case study: Learning from the Apollo 13 accident timeline and cause of failure
July 2018:
Accident case study: Create your personal minimums checklist for flying
June 2018:
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May 2018:
Fighter pilot skills every aviator needs to have to fly safe
April 2018:
The meaning of 'Ahead of the Power Curve'
March 2018:
Experience mountain flying (but get the proper training first)
February 2018:
Helping pilots learn from accident chains
January 2018:
Discover the hidden benefits of learning to fly








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Flight Chain App and its blog Ahead of the Power Curve are committed to reducing general aviation accidents, helping improve aviation safety, and growing the pilot population.