Prevention of Controlled Flight Into Terrain In General Aviation Operations

What is CFIT?
 

Controlled Flight into Terrain (CFIT) occurs when an airworthy aircraft under the control of a pilot is inadvertently flown into terrain, water, or an obstacle with inadequate awareness on the part of the pilot of the impending disaster.

The following actual incident and accident summaries illustrate some typical CFIT accident scenarios:
 

• At night in IMC, the pilot misread the NAV-DME due to fatigue. Read DME on wrong NAV radio, descended too early on back course LOC approach and penetrated prohibited airspace, after flying 7 hours and having been on duty for 10 hours. A low- altitude alert issued by the Approach Controller prevented an accident.
   
• The pilot likely lost situational awareness and inadvertently flew the aircraft into the ice surface while in controlled flight because of the combined effects of the lack of external visual references and weak instrument flying skills.
   
• The pilot continued flight in adverse weather conditions and probably did not have the necessary visual references to avoid hitting the steep slope of the mountain. Likely contributing to this accident was the pilot's over-reliance on GPS while attempting to maintain visual meteorological conditions ( VMC).
   
• During the overshoot from the approach to the airport, the pilot probably lost situational awareness as a result of spatial disorientation, unintentionally flying the aircraft into the ground.
   
• The pilot encountered weather conditions that were worse than forecast, and, in an attempt to maintain or regain visual contact with the ground in an area of low cloud and dense ground fog, descended and the aircraft struck the ground.
   

CFIT Accidents occur most frequently in GA operations, comprising 4.7% of all GA accidents and 32% of GA accidents in IMC. On average there are 1.4 fatalities per CFIT accident, versus 0.33 fatalities per GA accident overall.
 

• 17% of all GA fatalities are due to CFIT
   
• CFIT accidents are fatal 58% of the time.
   
• CFIT accidents occur 64% of the time in daytime and 36% at night
• 51% of CFIT accidents occur in IMC, 48% in VMC and 1% unknown.
   
• Impacted terrain was flat 45% and mountainous 55%.

Type Operation and Percentage of Accidents

Part Operation		% of CFIT Accidents
91	General Aviation	81
135	Air Taxi/ Commuter	17
133	Rotorcraft-external load operations	1
137	Agricultural	1

 

Aircraft Type and %of CFIT Accidents

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HFACS Analysis of 164 Fixed-Wing Accidents

Type of Error in HFACS	% of 164 Fixed-Wing GA CFIT Accidents
Decision Error	50
Skill-based Error	30
Violations	30
Perceptual	20

The Human Factors Analysis and Classification System (HFACS) has been applied to CFIT accidents.
 

• More fatal than non-fatal accidents were associated with violations.
• Decision errors were more often associated with non-fatal CFIT accidents.
   
• When weather was a factor, more CFIT accidents were associated with violations and decision errors.
   

Note that the HFACS data shows 50% of CFIT accidents were due to pilot judgment errors, thus we need to improve pilot decision making ( education, practical test standards, written exam questions).
 

Analysis also shows 30% skill based errors (feedback to CFIs, designated flight examiners, FBOs). With 30% of CFIT accidents due to violations, we have existing FAA responses to violations, but we also need to educate pilots that violations during conditions conducive to CFIT risk are major contributors to death. Finally, with 20% of CFIT accidents due to perceptual associations, we must continue to emphasize the illusions and hazards of flight due to spatial disorientation and visual illusions.
 

Phase of Flight and % of CFIT Accidents

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CFIT Countermeasures
 

Countermeasures for CFIT prevention can be grouped in two main categories: aircraft equipment and training/education. Findings from accident investigations have indicated that many CFIT accidents could have been avoided if some type of terrain warning system or an improved navigation system had been installed on the aircraft and/or if pilots were better informed of CFIT related hazards and how to avoid them.
 

Equipment
 

Advances in technology have resulted in cockpit equipment that can significantly improve a pilot's situation awareness. Some of this technology is now cost effective for general aviation applications.
 

Ground Proximity Warning Systems (GPWS) have been mandatory equipment on large transport aircraft for years and been instrumental in preventing some CFIT accidents. Terrain Awareness and Warning Systems (TAWS) have been developed with increased capabilities to replace GPWS. In addition, less capable but cost effective TAWS have been developed for the smaller aircraft market.
 

These systems compare the aircraft's present position, as determined from the aircraft's navigation system, with an onboard terrain database.
 

If there is a potential threat of collision with terrain, TAWS provides an aural and/or visual warning to the pilot, enabling corrective action to be taken even in instrument flight or night conditions.
 

Global Positioning Systems (GPS) are now used extensively throughout commercial and general aviation operations. Used correctly, these systems can provide increased navigation capability and accuracy, instrument approaches in locations where no ground-based approach aids are available and better situational awareness. All of these potential benefits can help to reduce the CFIT accident rate, particularly in circumstances involving flight in instrument conditions or visual flight in reduced or marginal visibility, both situations are potential factors in CFIT accidents.

 

Training
 

Specific training and education in the area of CFIT awareness/avoidance is perhaps more important than equipment improvements. In some countries CFIT avoidance training is mandatory for most commercial and business operations. Although the emphasis for this training has been on these types of operations, the statistics indicate that general aviation accidents account for the highest percentage of the overall CFIT accidents. Therefore, general aviation pilots should familiarize themselves with the flight circumstances typically associated with CFIT accidents and the countermeasures available to reduce the potential for these accidents.

For example the Flight Safety Foundation has a CFIT checklist available at: http://www.flightsafety.org/pdf/cfit_check.pdf.

 

The Flight Safety Foundation CFIT Checklist is on-line at: http://www.flightsafety.org/pdf/cfit_check.pdf
 

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NAFTA TRINATIONAL CFIT WORKING GROUP INITIATIVE

FOCAL POINTS
 

Dr. Stephen J.H. Véronneau   FAA Civil Aerospace Medical Institute PO Box 25082, Oklahoma City, OK 73125 405-954-1000; fax: 405-954-3705 http://www.cami.jccbi.gov/

 

 

Roger Ayotte   Jim McMenemy   Transport Canada, 330 Sparks Street Ottawa, Ontario K1A 0N8 613-990-1125, fax: 613-990-6215 http://www.tc.gc.ca/

 

Captain Mauro Gomez Peralta   Direccion General de Aeronautica Civil Director de Control Providencia 807-4 PISO Col. Del Valle C.P. 03100 Mexico D.F. 011-525-687-76-80, fax: 011-525-523-47-51 fax

 

Publication DOT/FAA/AM-400-02/2