.  
Off-airport emergency landings are excluded from this category. 

.  
To be used for occurrences during the landing phase. 

.  
Includes offside touchdowns on heliports, helidecks and other defined areas to be used wholly or in part for the arrival, departure and surface movement of helicopters (does not include helicopter unprepared or natural landing sites).

UNINTENDED FLIGHT IN IMC (UIMC)

Usage Notes:
.  
May be used as a precursor to CFIT, LOC–I or LALT.

.  
Applicable if the pilot was flying according to Visual Flight Rules (VFR), as defined in Annex 2 – Rules of the Air – to the Convention on International Civil Aviation, and by any reason found oneself inadvertently in IMC.

.  
Only to be used when loss of visual references is encountered.

.  
Only to be used if pilot not qualified to fly in IMC and/or aircraft not equipped to fly in IMC.

UNKNOWN OR UNDETERMINED (UNK)

Insufficient information exists to categorize the occurrence.
Usage Notes:
.  
Includes cases where the aircraft is missing. 

.  
Includes those occurrences where there is not enough information at hand to classify the occurrence or where additional information is expected in due course to better classify the occurrence. 

WIND SHEAR OR THUNDERSTORM (WSTRW)

Flight into wind shear or thunderstorm.
Usage Notes:
.  
Includes flight into wind shear and/or thunderstorm-related weather. 

.  
Includes inflight events related to hail.

.  
Includes events related to lightning strikes.

.  
Includes events related to heavy rain (not just in a thunderstorm).

.
Icing and turbulence encounters are coded separately (see ICE and TURB). 

ATTACHMENT A
SAMPLE OPERATIONAL GROUPING OF CATEGORIES

Airborne 
ABRUPT MANEUVRE  AMAN 
AIRPROX/TCAS ALERT/LOSS OF SEPARATION/NEAR MIDAIR  MAC 
COLLISIONS/MIDAIR COLLISIONS 
CONTROLLED FLIGHT INTO/TOWARD TERRAIN  CFIT 
FUEL RELATED  FUEL 
GLIDER TOWING RELATED EVENTS  GTOW 
LOSS OF CONTROL – INFLIGHT   LOC–I 
LOSS OF LIFTING CONDITIONS EN-ROUTE  LOLI 
LOW ALTITUDE OPERATIONS  LALT 
UNINTENDED FLIGHT IN IMC  UIMC 
Aircraft 

FIRE/SMOKE (NON-IMPACT) F–NI
SYSTEM/COMPONENT FAILURE OR MALFUNCTION (NON-POWERPLANT) SCF–NP
SYSTEM/COMPONENT FAILURE OR MALFUNCTION (POWERPLANT) SCF–PP

Ground Operations 
EVACUATION  EVAC 
FIRE/SMOKE (POST-IMPACT)  F–POST 
　
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