Lewis Vondy is a 39 year aviator, currently employed with Air Methods Corporation, one of the largest helicopter emergency medical services. Lead Check Airman in the AS365, Lead Instructor in Single Pilot IFR (SPIFR), and a Check Airman in the EC135. Prior U.S. Army helicopter pilot.
Rex Alexander is a 40 year aviator, President of Five Alpha LLC., Many years of experience in the commercial helicopter industry, helicopter emergency medical services, and prior U.S. Army helicopter pilot.
Kenny Keller and Gary Cleveland of Helicopter Online Ground School worked to bring these two experts together in one presentation to talk about the biggest cause of helicopter loss of control accidents, IIMC.
Helicopter Online Ground School has worked to make these free FAA webinars available to pilots on a regular basis.
Helicopter Online Ground School has the only "truly helicopter" instrument course available online. We were honored to add Taz Christman to our team for the project and his participation, among other achievements, landed him the award of 2018 Flight Instructor of the Year!
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Visual flight rules (VFR) flights that inadvertently or intentionally enter into instrument meteorological conditions (IMC) continue to be a significant safety hazard to general aviation (GA) flights. Although loss of control (LOC) and controlled flight into terrain (CFIT) accidents by VFR pilots in IMC typically account only for a proportion of the total number of GA accidents, such occurrences account for 75% of weather related GA fatalities.
NTSB statistics show that helicopter pilots who fly VFR into IMC conditions only have a 14% chance of surviving the event. This webinar is designed to help helicopter pilots tip this 86% fatal accident rate back in their favor.
the pilot should identify the risks that deteriorating en-route weather could present, particularly when the route is associated with any high ground, surface obstructions or proximity to controlled airspace, and consider how to manage those risks before the flight. In pre-flight planning, the pilot should consider not only what alternate courses of action will be available if the weather were to deteriorate, but also when those courses of action should be taken. For example, what would be the minimum visibility or cloud base needed to continue on track? Once airborne, these decisions are likely to be made under stress so pilots must also be aware of their own abilities and limitations, which may well be more limiting than the local regulations may require or the law demand.
All aircraft instruments are subject to pilot (mis)interpretation and have errors that generally increase with wear and age. Therefore, the pilot must understand correctly the flight instrument indications and limitations. Pre-flight checks to ensure the flight instruments are fully serviceable are critical. Encountering adverse flight conditions is not the time to discover an instrument(s) is not serviceable!
Accident statistics show that a pilot who has not been trained and qualified in instrument flying, or one whose instrument skills have eroded, will soon lose control of the aircraft if forced to fly solely by reference to flight instruments.
VFR Pilots may attempt to continue a VFR flight in IMC conditions for many reasons, such as:
Placing priority on the wrong things (e.g. loss of time or additional expense of a diversion or delay to the flight) when making decisions (sometimes referred to as “get-home-itis”)
Poor situational awareness perhaps as a result of pilots’ lack of experience in interpreting changing weather conditions once airborne.
Over-confidence leading to poor risk awareness because pilots overestimate their own abilities and are complacent about flying into adverse weather. They may believe that their limited PPL course instrument training will enable them to cope in instrument conditions for a sustained period.
Internal (personal) and external (social) pressure may be allowed to bias pilots’ decisions to continue the flight even when objective assessment of the situation suggests they should do otherwise. For example, when passengers are on board, a pilot may feel a strong responsibility to reach their destination sooner rather than later. Passengers may apply pressure to fly and this must be resisted.
To reduce the risk of an accident from inadvertent VFR flight into IMC, pilots need strategies to avoid adverse weather and a framework of actions to assist recovery if they inadvertently fly into IMC.
The first step to be taken by a VFR pilot to avoid encountering instrument meteorological conditions (IMC) is effective pre-flight planning. Pilots must be able to access comprehensive weather information to use at the planning stage. For a typical VFR flight, pilots should ensure that they obtain an area forecast covering the route; a forecast of the wind speed and direction valid for the duration of the flight; at the lower flight levels local conditions can have a dramatic effect on the weather. Where available, Terminal Aerodrome Forecasts (TAFs) and Meteorological Terminal Air Report (METAR) for the destination, destination alternate and all other airfields en-route should be obtained. If the specific airfield or strip does not have these available, the data for surrounding airfields will still be a useful source of information to aid decision making. All this information can then be comprehensively analysed and from this the pilot can make a holistic decision on whether the flight can be made safely and which route is most suitable. Once airborne, the pilot should adopt pre-planned alternative courses of action as necessary to avoid flying into IMC. If, despite these precautions, the pilot enters IMC the priorities are: (1) Maintain control of the aeroplane; (2) Obtain appropriate ATC assistance in turning back or otherwise heading the aeroplane safely back to VMC conditions.
Typically, VFR rules require the aircraft to remain 1000’ vertically from cloud. In certain classes of airspace subject to additional conditions, an aircraft can operate VFR “clear of cloud with the surface in sight”. In this situation the cruising level should be adjusted to be no closer than 300’ below the cloud base. This allows for any up draught that may cause an inadvertent increase in altitude as well any issues such as not having the aircraft in an accurate trimmed condition (and the fact that close to the cloud base, relative humidity is likely to be close to 100%, and it is possible that cloud may form around the aircraft).
Whilst cruising, the standard working cycle of Lookout/Attitude/Instruments should be maintained with regular checks on the weather ahead as part of the lookout scan. This could be challenging, as the weather transitions are often rather subtle. The human eye can become so accustomed to progressive small changes in light, colour, and motion that it no longer “sees” an accurate picture. In deteriorating weather, the reduction in visibility and contrast can occur gradually, and it may be quite some time before the pilot senses that the weather conditions have deteriorated significantly.
The first clue of deteriorating weather can often be the need to gradually reduce cruising level to maintain VMC. Reference to the pre-planned "Minimum VFR Altitude to Continue" figure will alert the pilot as to when further descent is not safe and a diversion is required before an inadvertent entry into IMC occurs.
Diversion options should have been considered and established at the pre-flight planning stage. When planning a flight across higher ground it is useful to have identified ‘escape route’ options towards lower ground.
VFR pilots should assume they are in IMC conditions anytime they are unable to maintain aircraft attitude control by reference to the natural horizon, regardless of the circumstances or the prevailing weather conditions. In addition, a VFR pilot should accept that they are effectively in IMC anytime they are unable to navigate or establish geographical position by visual reference to landmarks on the surface unless they have planned and are legally able to operate “VFR on top”. Such situations must be accepted by the pilot involved as a genuine emergency, requiring immediate action.
Pilots must understand that unless they are trained, qualified, and current in the control of an airplane solely by reference to flight instruments, they will not be able to do so for any length of time.
Many hours of VFR flying using the attitude indicator as a reference for airplane control in conditions of low visibility may give a pilot a false sense of security based on an overestimation of his personal ability to control the airplane solely by reference to instruments. In visual meteorological conditions, even though the pilot may think he/she is controlling the airplane by instrument reference, the pilot receives an impression of the natural horizon and may subconsciously rely on it more than the cockpit attitude indicator. If all vestiges of the natural horizon subsequently disappear, the untrained instrument pilot is likely to become spatially disorientated, which is likely to lead to loss of control.
Once the pilot recognises that they have entered IMC conditions, they should understand that the only way to control the airplane safely is by using and trusting the flight instruments. The pilot should make a firm decision to change from visual reference to instrument flight if possible before visual references are completely lost. The pilot should initially concentrate on the attitude indicator and select and maintain the correct attitude for straight and level flight. Once this is achieved, the pilot must concentrate on the AI limiting glances away from the AI for essential checks only – e.g. the RPM to confirm appropriate power is set. It is important not to try to mix searching for external clues as to the attitude of the aircraft with instrument flying.
The pilot should understand that the most important concern is to keep the wings level. An uncontrolled bank may lead to spiral dive and loss of control. The pilot must believe what the AI shows about the aeroplane’s attitude regardless of sensory input. vestibular organs (in the inner ear) is unreliable in flight when unaccompanied by relevant visual information. The sensory areas of the inner ear cannot detect slight changes in angular acceleration, nor can they accurately sense changes that occur at a uniform rate over a period. On the other hand, false sensations are often generated due simply to movements of the head and may lead the pilot to believe the attitude of the airplane has changed when, in fact, it has not. If the pilot has managed to achieve straight, stable flight, do not make any control movement unless the AI shows that it is necessary, and even then make only small control inputs.
Other receptors found throughout the body, known as somatosensory receptors (commonly referred to giving feeling and G forces) located all over the skin, bones, joints, skeletal muscles, internal organs and the parts of the cardiovascular system, will also be providing information to the brain. This information can be in conflict with the visual and vestibular senses. These false or conflicting sensations can result in the pilot experiencing spatial disorientation even when in VMC. Particularly during flight in poor visibility or in cloud all this can be catastrophic. The outcome may develop into what is often called a “graveyard spiral”. This name is self explanatory.
Having established stable straight and level flight, the next step is to consider ice protection. In most light single-engine aircraft this may be limited to selecting the pitot heat on and selecting the carburetor heat to “Hot”.
Next we begin a gradual climb, declare an emergency, and get assistance with vectoring back to VFR flight.
All controllers are trained for such occurrences and will be best placed to enable the pilot to maintain terrain clearance and return to VFR conditions. Often they will request the pilot to set the transponder to a discrete code, unless the pilot has already set 7700 as part of the mayday. The pilot must not allow setting the transponder code to distract from maintaining close attention on the AI. Setting the transponder will identify the aircraft on radar so allowing the aircraft to be vectored.
In this situation the pilot is best to remember the three “C’s” – Contact, Confess, and Comply. It would be unusual for a controller to ask the pilot in these circumstances to do combined maneuvers such as descending turns. Do not attempt to make anything other than a simple heading change or a climb/descent to keep the flying task as simple as possible.
This was a live FAA webinar on December 8th, 2018.
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