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 fourth video addresses UIMC in night operations.
UIMC: a well-known severe risk!
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.
UIMC in Night Operations: an even more serious risk!
This fourth video focuses on UIMC in night operations.
Fatal UIMC accidents are more frequent at night
In the video Robinson Helicopter Safety Notice 26: Night Flight - USHST, Tim Tucker reminds that that around 65% of all fatal accidents caused by flying into IIMC occur at night. Flying at night in bad weather or even marginal weather is more risky and can result in catastrophic consequences!
Fly only when the weather is clear and increase personal minima
Never fly at night unless the weather is clear with unlimited or very high ceilings and plenty of sky or ground lights for reference. At night, increase your personal minimums and stick to them all through the flight!
We see less in the dark
In the dark you won’t be able to see wires, the bottom of the clouds or low hanging fog.
It’s also difficult to assess altitude because there is no horizon for reference. You may not realise it until you are in the cloud and then lose all outside visual references. Avoid mountainous terrain and other geographical features that might be hard to see in flight.
Also, think about emergency landing spots and how easy they are to identify when something bad is happening, in the dark! Planning your route along VORs, highways and cities can make things easier for you.
Flying at night in poor or marginal weather can be deadly
The risk of UIMC seriously increases when flying at night in poor or even marginal weather.
Refer to Robinson Helicopter Safety Notice 26 Night Flight Plus Bad Weather Can Be Deadly.
And the risk increases even more in poor or lack of lightening, for instance when the ground lighting network suffers an electrical blackout.
What if weather or flight visibility deteriorate?
If flight visibility deteriorates or you are approaching bad weather at night, don’t take any chance! Resist the pressure to complete the flight especially if you are ‘almost there’, a powerful tendency known as Get-there-itis or plan continuation bias (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).
Your options
Especially at night, resist the pressure to continue flying to destination when the weather or flight visibility deteriorate.
If the situation worsens or if in doubt, don’t push! Your 3 options are:
- Divert
- Return to base, or
- Land and LIVE: find a suitable landing site rather than pushing into bad weather where a crash could occur.
Key points from this video
- Never fly at night unless the weather is clear with unlimited or very high ceilings and plenty of sky or ground lights for reference.
- At night, increase your personal minimums and stick to them all through the flight.
- If you are approaching bad weather, resist the pressure to complete the flight: divert, return to base or Land & LIVE!
This other video with Mona Seeberger released in 2020 provides additional tips: Night Pre-Flight | EASA Community (europa.eu).
Standardised European Rules of the Air
Visibility and distance from cloud minima are identified in Table S5-1 .5001(c) of SERA.5001 VMC.
Consult also to SERA.5005 Visual flight rules, AMCs and GMs.
References
Robinson Helicopter Safety Notice 26: Night Flight - USHST Tim Tucker
Robinson Helicopter Safety Notice 26 Night Flight Plus Bad Weather Can Be Deadly
HAI Land & LIVE Program - Helicopter Association International (rotor.org)
When IMC is Imminent by Bruce Webb
Night Pre-Flight | EASA Community (europa.eu)
Workshop on Inadvertent entry into IMC (IIMC) - Rotorcraft & VTOL Symposium 2022 - YouTube
EHEST Video Degraded Visual Environment and Loss of Control | EASA (europa.eu)
Unintended IMC - An Evening with Claude Vuichard | EASA Community (europa.eu)
What is flight visibility and why do we care? Bruce Webb - YouTube
You are not allowed to comment on content in a group you are not member of.
Rotorcraft