SURVIVING INADVERTENT
FLIGHT INTO IMC
MIKE SHAMA
AIM
The aim of this briefing is to outline why inadvertent flight into IMC is so
dangerous, what can happen to you, and how to avoid/recover
CONTENTS
• Dangers
• Spatial Disorientation
• How to Avoid IIMC
• Immediate Actions - 5 C’s
• Practice
What is IIMC
• Inadvertent entry into IMC (IIMC) is a situation
where deteriorating weather prevents you from
flying under visual meteorological conditions
when you were planning to fly under VFR.
• IIMC can also be stated as loss of horizon
references and/or an accompanying loss of visual
contact with the ground.
Dangers
• NTSB 2011: 45 of the 52 IIMC accidents occurring
that year were fatal
• 86% giving you a 14% survivability rate
• University of Illinois: IIMC by pilots with NO
instrument training = avg 178 seconds till loss of
control
• Spatial Disorientation
• CFIT
• Brown Out or White Out
Contributing Factors
• Improper Judgment
• Overconfidence
• Pressure on the Pilot
• Decision Making
• Poor pre-flight preparation
• Night or mountainous terrain
• Expectation of Success
• Visual
• 90% of our spatial orientation is derived from visual inputs
• Vestibular & Proprioceptive
• No amount of training or practice
can allow us to correctly interpret
erroneous vestibular sensations!!!
Spatial Disorientation
Preflight/Weather Planning
• Determination of enroute weather to avoid IIMC
• Wx charts, forecasts, local wx trends
• In-flight weather abort procedures
• Flight Plan?
How to Avoid IIMC
• Avoid flight in Marginal VFR (MVFR).
• Use planned Enroute Decision Points (EDP)s.
• Recognize signs of deteriorating weather,
• Wx charts, forecasts, local wx trends
• In-flight weather abort procedures
• Know your terrain
• Assess the situation: If signs back up the warnings,
decide to land or turn around before you go IIMC.
Immediate Actions - 4 C’s
• Control
• Fly the aircraft
• Climb
• Terrain
• Course
• Diversion airfield? Be careful of the 180° turn
• Communicate
• ATC: Tell them your situation and need for help.
• Comply with instructions
• Don’t fear repercussions
Practice
• Discuss how these encounters happen in the real
world
• IIMC foggles training
• Think 4 C’s
• Think CFIT
• Leave EGO out if it
SUMMARY
• Pilot Decision Making (PDM) is a defence against:
• Overestimating Skill
• Pushing a/c beyond limits
• Underestimating the environment/weather
• Avoiding IIMC is the priority
• Remember your Immediate Actions
• If there is doubt, there is NO doubt: DON’T GO
• Fly Prepared, Fly Safe
QUESTIONS
SURVIVING INADVERTENT
FLIGHT INTO IMC
MIKE SHAMA

Surviving Inadvertent IMC

  • 1.
  • 2.
    AIM The aim ofthis briefing is to outline why inadvertent flight into IMC is so dangerous, what can happen to you, and how to avoid/recover
  • 3.
    CONTENTS • Dangers • SpatialDisorientation • How to Avoid IIMC • Immediate Actions - 5 C’s • Practice
  • 4.
    What is IIMC •Inadvertent entry into IMC (IIMC) is a situation where deteriorating weather prevents you from flying under visual meteorological conditions when you were planning to fly under VFR. • IIMC can also be stated as loss of horizon references and/or an accompanying loss of visual contact with the ground.
  • 5.
    Dangers • NTSB 2011:45 of the 52 IIMC accidents occurring that year were fatal • 86% giving you a 14% survivability rate • University of Illinois: IIMC by pilots with NO instrument training = avg 178 seconds till loss of control • Spatial Disorientation • CFIT • Brown Out or White Out
  • 6.
    Contributing Factors • ImproperJudgment • Overconfidence • Pressure on the Pilot • Decision Making • Poor pre-flight preparation • Night or mountainous terrain • Expectation of Success
  • 7.
    • Visual • 90%of our spatial orientation is derived from visual inputs • Vestibular & Proprioceptive • No amount of training or practice can allow us to correctly interpret erroneous vestibular sensations!!! Spatial Disorientation
  • 8.
    Preflight/Weather Planning • Determinationof enroute weather to avoid IIMC • Wx charts, forecasts, local wx trends • In-flight weather abort procedures • Flight Plan?
  • 9.
    How to AvoidIIMC • Avoid flight in Marginal VFR (MVFR). • Use planned Enroute Decision Points (EDP)s. • Recognize signs of deteriorating weather, • Wx charts, forecasts, local wx trends • In-flight weather abort procedures • Know your terrain • Assess the situation: If signs back up the warnings, decide to land or turn around before you go IIMC.
  • 10.
    Immediate Actions -4 C’s • Control • Fly the aircraft • Climb • Terrain • Course • Diversion airfield? Be careful of the 180° turn • Communicate • ATC: Tell them your situation and need for help. • Comply with instructions • Don’t fear repercussions
  • 11.
    Practice • Discuss howthese encounters happen in the real world • IIMC foggles training • Think 4 C’s • Think CFIT • Leave EGO out if it
  • 12.
    SUMMARY • Pilot DecisionMaking (PDM) is a defence against: • Overestimating Skill • Pushing a/c beyond limits • Underestimating the environment/weather • Avoiding IIMC is the priority • Remember your Immediate Actions • If there is doubt, there is NO doubt: DON’T GO • Fly Prepared, Fly Safe
  • 13.
  • 14.

Editor's Notes

  • #7 Improper Judgment: Not being able to judge whether pilot is near IMC Overconfidence: statistical sampling of pilots reveals most pilots think they possess greater flying skill, are less likely to take risks in flight, and are less likely than their peers to experience an accident. Most VFR pilots believe they are less likely than others to experience a VFR-into-IMC accident and believe they are more capable than others at avoiding and successfully flying out of IMC. Pressure on the Pilot: Bosses, money, job security, passengers? Decision Making: Imagine -> 100% chance of R80 loss (Land now/Divert now/Delay or cancel flight = loss of revenue, cost increases, impact on contract), or 80% chance of R100 loss (Small chance of making it through, but a high chance of losing it all, of crashing and dying) Poor pre-flight preparation: Many examples of pilots who failed to get any sort of official weather briefing before departing Night or mountainous terrain: Reduced visual references, smaller margin for error, must be properly trained Expectation of Success: Pilots take off without a back-up plan, automatically assuming they'll successfully complete the flight. Without a Plan B, they have no other course, literally, other than to continue on, developing a kind of tunnel vision that seems to lock up the brain as conditions deteriorate. It’s like driving a car with the fuel on E often … you get used to pushing the envelope
  • #8 Vestibular system: the sensory system that provides the leading contribution about movement and sense of balance Proprioceptors in skeletal striated muscles and in joints, the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement
  • #11 Control: Fly the aircraft. Refocus the scan inside the cockpit to the primary flight instruments – airspeed, altitude, and attitude Climb: As soon as the aircraft is under control by reference to the instruments, a controlled climb should be initiated. Inadvertent IMC encounters often occur at low altitudes where rising terrain poses a serious threat. The pilot should initiate a straight ahead controlled climb to an altitude that will provide obstruction clearance in the area of operation. Always review Maximum Elevation Figures (MEF) on VFR charts prior to departure. Course: After the aircraft is in a controlled climb, the pilot can elect to turn to a new heading if known obstacles are ahead and/or divert to a different location with better known or forecast weather conditions. Communicate: After the pilot has control of the aircraft, initiated a climb, and on course, they should communicate with ATC regarding their intentions and need for assistance. Careful preflight planning will allow a pilot to focus their attention on maintaining control of the aircraft and reduce the distraction of having to formulate a complete plan in the midst of a dangerous situation. Pilots must be prepared to deal with (recognize & accept) such inadvertent IMC encounters whenever they occur in a reliably disciplined and practiced manner