UIMC - Before Take-Off

Michel MASSON • 28 September 2023
in community Rotorcraft
1 comment

EASA and ESPN-R present a series of 4 new videos with Mona Seeberger on UIMC (Unintended entry into Instruments Meteorological Conditions), also called IIMC (Inadvertent entry into Instruments Meteorological Conditions) or inadvertent VFR into IMC (Visual Flight Rules flight into Instrument Meteorological Conditions).

Despite UIMC being a well-known severe risk, fatal accidents continue to occur, calling for sustaining the efforts and promotion. These new videos remind some basic principles and actions to avoid UIMC and prevent related accidents. This first video focuses on UIMC avoidance before take-off.

UIMC: A key risk for Rotorcraft Operations

UIMC is a well-known severe risk that can result in various accident types, notably Loss of Control In-flight (LOC-I), Control Flight into Terrain CFIT, Collisions with obstacles or cables especially in Low Altitude Operations (LALT), and Mid-Air Collision (MAC).

UIMC is addressed by many different organisations, including EASA, FAA and other National Aviation Authorities in Europe and worldwide, Accident Investigation Boards, EHEST and ESPN-R, USHST, IHST and VAST, HAI, EHA and national associations, manufacturers, operators, training schools, research organisations and academia, and pilot and operator associations. UIMC is also addressed on social media.

The risk and solutions are known but accidents continue to happen. This means it’s important to continually remind ourselves of the key messages and promote the topic of widely as possible in the Rotorcraft and VTOL Community.

This series of 4 new videos reminds some basic principles and actions to take to avoid UIMC and prevent accidents. Share the videos, the articles and other resources in your organisations and with your colleagues and friends in the industry.

Actions to take before take-off 

This first video focuses on actions to take before take-off. Whether you are a private or commercial pilot, it's vital to make the right preparation for every flight. This will help avoiding a UIMC encounter.

Risk assessment and mitigation tools and Apps 

Perform a pre-Flight Risk Assessment and use a risk assessment tool like the Flight Risk Assessment Tool (FRAT) or Apps provided by helicopter manufacturers or your organisation to evaluate and mitigate the risks before you take to the sky.

ESPN-R promotes 3 safety Apps by Airbus Helicopters, Leonardo Helicopters, and NGPT (Next Generation Flight Training) in the EASA Community Rotorcraft article Safety Apps | EASA Community (europa.eu).

Getting weather information and planning your flight 

Specifically for weather, know where to get information and how to interpret it. Most flight-planning and navigation software include whether information. Plan your route using Enroute Decision Points and set your personal minimums. Consider the conditions enroute that you could encounter and how this affects your ability to avoid weather, terrain and obstacles. Consider that the situation may evolve in-flight and define a recovery plan if conditions deteriorate unexpectedly. You always have 3 options: divert, return to base or Land and LIVE.

To fly or not to fly? 

Make a carefully reasoned GO / NO GO decision. If in doubt, delay or cancel the flight!

Don’t let self-induced pressure influence your judgement. Get-there-it is (the desire to try and reach your destination no matter what the circumstances and, once in the air, the resistance to adapt plan when the conditions would require so) is a powerful bias that can lead to fatal accidents! Recognise when you fall in this mood and resist the pressure to fly. I did it before and it went well? Yes, perhaps, but it won’t always. Don’t take chances!

If you are an operator watching this video, always support your pilots in the decisions they make. Commercial and mission pressure, including from passengers, is one of the biggest killers in aviation!

Helicopter Airmanship | EASA Community (europa.eu) and From Take-Off to Landing | EASA Community (europa.eu) provide additional tips on weather and VFR navigation.

Flying IFR? 

If you are IFR-qualified, consider an IFR option. On a personal level, the effort of obtaining an Instrument Rating is worth it, because it gives you more options. 

Key points from this video 

  • Take the time to prepare every flight to help avoid UIMC. 
  • Perform a risk assessment to identify any key risks, set personal minima and prepare for the unexpected.
  • If in doubt delay or cancel the flight.


Pre-Flight Risk Assessment and Attitude | EASA Community (europa.eu)

FRAT Tool - NGFT Solutions for Commercial Aviation

Safety Apps | EASA Community (europa.eu) HAI Land & LIVE Program - Helicopter Association International (rotor.org) Helicopter Airmanship | EASA Community (europa.eu) From Take-Off to Landing | EASA Community (europa.eu)

EHEST Leaflet HE 13 Weather Threat for VMC Flights | EASA (europa.eu)

EGAST Leaflet GA 3 Weather Anticipation | EASA (europa.eu)

Weather Threats for VMC Flights | EASA Community (europa.eu)

Weather Threats for VMC Flights - Flying Under IFR | EASA Community (europa.eu)

Unintended IMC - An Evening with Claude Vuichard | EASA Community (europa.eu)

Preventing and Recovering from Unintended IMC | EASA Community (europa.eu)

Weather in Europe can be challenging | EASA Community (europa.eu)

Rotorcraft Safety Technologies: The VAST Report | EASA Community (europa.eu)

Technologies with Safety Benefits | EASA Community (europa.eu)

Visit 56 Seconds to Live – USHST.

EASA Sunny Swift issues

Intended for fixed-wing General Aviation pilots and instructors, the safety messages passed in these Sunny Swift issues well transfer to helicopter operations:

Sunny Swift: Easier and safer flying in IFR - Issue 11 | EASA (europa.eu) Sunny Swift: Weather briefing process - Issue 17 | EASA (europa.eu)

Sunny Swift: Weather radar information - Issue 12 | EASA (europa.eu)

Sunny Swift: Horizon visibility in Night VFR - Issue 33 | EASA (europa.eu)

Sunny Swift: New Technologies - Issue 18 | EASA (europa.eu)

Sunny Swift: Exchange of experiences - Issue 10 | EASA (europa.eu)

Sunny Swift: TAF, what it means in practice - Issue 21 | EASA (europa.eu)

Sunny Swift: Winter Planning - Issue 9 | EASA (europa.eu)

Visit Sunny Swift – Flight Instructor | EASA (europa.eu).





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