CONTROLLED FLIGHT INTO TERRAIN (CFIT)
When an airworthy aircraft or helicopter under the command of a qualified pilot, is inadvertently or without prior knowledge is flown into terrain, water or obstructions, is called CFIT. Most of the CFIT accidents are fatal and almost always a pilot error.
CFIT mostly occurs when visual cues are lost due to flying during night or into clouds, fog or poor visibility conditions. Under such conditions, Pilots may get spatially disorientated, loose Situational Awareness and meets with CFIT accidents. In addition visual illusions, also add to the CFIT accident statistics.
CFIT is more likely to occur over water, hilly areas, long stretches of forested or desert terrain and during Night, due to lack of prominent visual cues.
Most of the CFIT accidents occur during final approach and landing or during take-off and initial climb. However, Number of Aircraft/Helicopter CFIT accidents have occurred during cruise or manoeuvring flight.
Causes of CFIT
- Proper Flight Planning, Preparations.
- Adequate weather briefing, knowledge and intelligent monitoring of weather.
- Proper analysis of terrain with particular emphasis on Minimum Enroute Altitude, Minimum Safe or Sector Altitude, Minimum off route altitude (MORA),Grid MORA, Minimum Descent Altitude, obstructions around runways, helipads, towers, pylons, power, Cable Car/ trolley cables particularly in the mountains.
- Knowledge about SOP’s, Check List, Procedures, Approach, Enroute, Let down Charts , Weather Radar, GPS, Flight Management System, Automatic Flight Control System, Automation, Electronic Flight Instrumentation System, ILS, VOR,EGPWS,DME.
- Knowledge about Spatial Disorientation, Visual Illusions.
- Situational Awareness- Horizontal, Vertical and overall.
- Correct Altimeter Settings and Cross Check between PF and PM.
- Adequate CRM and Proper Communication.
- Compliance with SOP’s, Rules, Regulations.
- Lack of proper configuration and verification of the flight management computer for the profile approach.
- Inadequate Vertical Mode Selections of the Aircraft Flight Control System (AFCS).
- Inadequate or delayed response to the Warning Alerts of EGPWS/Terrain Awareness and Warning System.
- Inadequate or delayed Missed Approach and Go around Flight Path.
- Lateral and/or vertical deviation from intended flight path.
- Loss of terrain separation.
- Low Energy State during Approach / Unstable Approach.
- Inadequate Response to Wind Sheer Warning.
- Continued approach, when below DA (H) or MDA (H), after loss of visual references.
- Unstable approach and Failure to Go Around in time.
- Late or inadequate response to MSAW warning.
- Lack of effective flight path control during go-around.
- Failure to follow published missed-approach procedure.
- Inadequate fuel management.
- Fatigue and Stress.
- Interruptions / Distractions.
- Overconfidence, Complacency, Macho Attitude.
- VIP, Commercial, Peer and Self Imposed Pressures.
- Lack of effective and result oriented Simulator Training, Flight and Ground Training, CRM, All Weather Operations.
- Inadequate supervision, lack of monitoring by the Senior Management and Accountable Managers.
- Hazardous Attitudes like Ante Authority, Invulnerability, Impulsiveness, Macho and Resignation.
- Lack of currency in hands on flying, instrument flying.
- Lack of communication, Proper Pre Flight Briefing, Pre Descent, Approach Briefing and Debriefing.
- Lack of teamwork and synergy.
- Distraction/ loss of Attention.
- Poorly developed and outdated Procedures, SOP’s.
- Poor Decision Making, Delayed Decision, Fixation, Distraction.
- Not knowing or not following the Golden Rule in Aviation which is Aviate-Navigate-Communicate.
- Human performance limitations and deficiencies.
- Cockpit Gradient/Authority Gradient/Power Distance which takes away the ability of the Co Pilot or First Officer to Speak up or correct the Captain when he is doing something wrong. Lack of assertiveness by the Co Pilot or First Officer.
- Single Pilot aircraft or Helicopters are more susceptible to CFIT.
- Duck under Syndrome or Scud Running.
- Flying visually in IMC conditions or mixing instrument flying and visual flying.
- Exceeding the laid down limitations.
- Misunderstanding or misinterpretation of ATC instructions or blindly following ATC instructions.
- Automated “MINIMUM” alert not activated.
- Inadequate response to the EGPWS alert.
- EGPWS software was not updated.
- Stabilized criteria is not respected.
- Failed to monitor the aircraft’s altitude during the approach.
- The relevant weather was not provided to the flight crew.
- Delayed decision to execute missed approach when unstable approach or unable to see visual reference below MDA(H).
- For helicopter pilots, reluctance to land at suitable place if unable to continue flight due weather.
- Prevention of CFIT Accidents.
- Planning, preparation for the flight needs to be thorough.
- Obtain proper Met Briefing, forecast and interpret the weather to see how it will impact on your Flight.
- Be knowledgeable about the hazards of flying during pre-monsoon (Norwesters or Kal Baisakhi), Monsoons, Foggy Winter Months, Wind Shear, Western Disturbances, Cyclones, Tsunami etc.
- Improve your knowledge about the weather and how to interpret the weather from the various websites like IMD, Acu Weather, Sky Met and Meteo Earth Etc.
- Make good use of the information available from METARS, ATIS, about the weather, runway conditions and act accordingly in time. Respect the Weather and do not press on in adverse weather.
- ATC, Met and Company dispatch, must ensure that updated weather information are provided to the Pilots.
- Thorough knowledge of Terrain, highest obstructions, Minimum Enroute altitude, Minimum Sector or Safe Altitude, Minimum Off route Altitude, obstructions in the approach path to the Runway or the Helipad and obstructions around the Airport, Helipads. Hilly reason may have Chair Car trolley cables or power cables, communication cables, transmission towers. Knowledge of these and good look out while flying in the hills particularly for helicopter pilots who fly along the valleys at low levels.
- Captain, Co Pilot or First Officer should be having good knowledge about the Aircraft, Helicopter, its systems, Avionics, Nav Aids, approach and let down charts, Jepson charts, Weather Radar, Flight Management System, Automatic Flight Control System, SOP’s, Rules, Regulations, Spatial disorientation, Visual Illusions, Situational awareness, recovery from unusual attitudes, recovery from wind shear, stable approach, missed approach procedure, Take off and Go Around Mode switch, SIDS and STAR’s, ILS, Non Precision CDFA approaches.
- Carry our proper risk assessment of the flight in coordination with the other crew, taking all the factors into consideration and decide on minimums for the flight which should be respected.
- Undertake comprehensive pre-flight, pre decent and Approach briefing of the crew covering the aspects about weather, terrain, obstructions, type of approach, runway condition, winds and division of duties and responsibilities between Captain and Co Pilot or First Officer.
- Follow the SOP meticulously. If you feel that SOP is not properly drafted and may compromise safety, it should be reviewed, updated and approved.
- Always keep in mind the Golden Rule in Aviation-Aviate-Navigate-Communicate and make sure that at least one Pilot is flying all the time.
- Beware of overconfidence, complacency, distraction, Fixation, lack of attention which may lead to loss of situational awareness.
- Be Situationally Aware particularly Horizontal and Vertical situational awareness at all times.
- Know your capabilities and limitations.
- Be very careful in entering data into computers, FMS, AFCS, GPS etc and selection of correct frequencies must be ensured and cross checked.
- Correct Altimeter setting must be entered and ensure cross check and call outs between Captain and Co Pilot and with radio Altimeter. Knowledge of the altitudes for changing from QNH to QNE and vice versa is essential.
- Remain current with hands on flying, instrument flying and be knowledgeable to recover from unusual attitudes, wind shear.
- Take timely decision to execute missed approach and diversion. No questions will be asked by DGCA, ATC or Operator if pilots execute missed approach or divert due unstable approach or weather conditions (DGCA CAR on ALL Weather Operations).
- Helicopter pilots should not hesitate to land at a suitable place if unable to continue the flight due weather (DGCA, ASC 09/2013).
- Do not descend in IMC conditions or under cast conditions unless sure of the terrain or following established procedures under radar surveillance.
- Do not carry out spiral descent or descend through hole since it may lead to special disorientation. Descend in a race course pattern if required.
- Do not succumb to commercial, on time performance, VIP, passenger, peer or self-imposed pressures to undertake flight in the face of adverse weather conditions. Always take a professional well considered decision.
- Get Homitis, get thereitis and mind set should be kept under check and no chances should be taken with the safety of the aircraft, crew and passengers.
- Do not follow ATC instructions blindly and be situationally aware. If the ATC gives you a radial to fly which is taking you into weather, tell ATC unable and ask for another radial. If ATC gives you altitude to climb or decent which may put you in conflict with other traffic or with your minimum safe altitude, advise the ATC accordingly. Listen out the ATC instructions carefully and don’t hesitate to verify if in doubt.
- Keep open atmosphere in the cockpit where crew members are free to give inputs, particularly related to safety of the aircraft/helicopter without any hesitation, fear, apprehension, snubbing or reprisals.
- The Co Pilot/First Officer should be given freedom to be assertive and encouraged by Captain to correct or caution the Captain and even take over control if the Captain continues the approach in spite of the approach being unstable or without sighting the runway or any of the runway clues at MDA (H).
- Do not undertake the Flight if you are stressed, fatigued or unwell. Be very careful while taking flight during Window of Circadian Low and be aware of Human Performance Limitations.
- No decision should be taken if it is influenced by hazardous attitudes like Ante Authority, Impulsivity, Invulnerability, Macho or Resignation.
- Operators and Pilots also must ensure to conduct a proper pre-flight planning session and familiarize themselves with the terrain that may surround them during their flight, as terrain familiarization is critical to safe visual operations, in particular at night
- CDFA techniques contribute to a stabilized approach. Hence, the operators should develop procedures and train pilots to fly a stabilized CDFA.
- Effective crew coordination and crew performance, and in general CRM principles and behaviours can reduce pilots’ workload and decrease the probability of human errors.
- Enhancing pilot performance and complacency, both in normal and abnormal circumstances, will empower pilots to intervene, with greater confidence and competence, to prevent any environmental threats and hazards that could lead to high-risk outcomes. Operators must ensure that their training programs robustly address potential deficiencies, environmental, technical/non-technical factors such as human factors, air carrier’s SOPs.
- Encourage operators to review their procedures for responding to alerts on final approach to ensure that these procedures are sufficient to enable pilots to avoid impact with terrain or obstacles in such situations.
- Operators should always ensure that their EGPWS software is update to date.
- Pilots’ knowledge of aircraft systems, aircraft performance and normal/abnormal procedures is vital to ensure that they do not find themselves in unexpected situations from which they cannot immediately recover.
- Pilots must also be keenly aware of the risks of CFIT, the circumstances in which those risks are greatest and the best strategies for maintaining an accurate picture of their horizontal and vertical situation.
- Pilots’ competence in recognizing and responding to potential CFIT must be realistically trained and tested in recurrent simulator training sessions, using examples from operational experience.
- Analysis of the causes of CFIT accidents should be included in the training courses to help pilots to understand their own limitations and recognize when an undesirable situation is developing.
- Learn an escape manoeuvre and techniques designed to enhance the possibility of survival.
- Improved monitoring and cross-checking are methods that can prevent many of the accidents
- Good CRM behaviour and Pilot Monitoring can help to mitigate CFIT accidents.
- Operational procedures can also provide CFIT risk mitigations by avoiding non-precision approaches especially in high risk destinations or adopting risk reducing strategies such as CDFA or PBN approaches.
Pilot in command should be aware of the risks involved when transitioning from visual to instrument or from instrument to visual procedures on take-off or landing.
Helicopter pilots are more likely to get into CFIT conditions since they fly at low levels in hostile terrain. In addition to adverse weather conditions, environmental factors such as time of day, minimal light, shadows, darkness, sun glare, cockpit blind spots, fatigue, or other such factors may result in the pilot losing situational awareness and hitting an obstacle or impacting the ground.
Even if a Pilot is aware of the obstructions and environmental factors, He/She may not be able to see the danger in time or may see the danger but fail to react in time to avoid collision.
Flying in the hills along the valleys can result in a CFIT accident if a power line or cable is strung between the hills. Flying up a box canyon and not being able to fly up and out of it before impacting terrain. Flying over rising terrain that exceeds an aircraft’s/helicopters ability or performance to climb away from the terrain.
Pilots should be aware about the adverse effects of high density altitude which may lead to low reserve of power with consequent large radius of turn, at high altitudes. Under such conditions, manoeuvring the helicopter in narrow valleys may lead to collision with terrain.
Helicopter pilots, particularly, must be fully prepared, knowledgeable about the weather, environmental factors, terrain, obstructions, and adverse effects of high density altitude on performance, performance limitation of the helicopter, disorientation, snow blindness, icing and strong vertical and horizontal wind shear etc. Remember mountain flying in adverse weather conditions is a deadly situation.
Never take chances with weather, particularly, in the hills, high seas and night.
Analysis of number of accidents/serious incidents have highlighted following issues related to safety and for prevention of CFIT accidents.
Situational Awareness has been found deficient in number of accidents analysed. It is recommended that operators increase training on maintaining situational awareness at all times, especially when close to the ground, and provide pilots with appropriate language and procedures to communicate, and respond to, positional concerns without delay.
Procedural non-compliance is a common factor in CFIT accidents. It is recommended that operators promote and enforce a culture of universal compliance with policies and procedures, unless unusual circumstances directly affecting safety dictates otherwise. Such situations also need to be trained.
Emergency checklists are essential tools that flight crews use to respond to serious and time-critical situations. The lists must be well designed and clear; and adherence to these lists must be trained.
SOPs for communication between pilots on approach frequently give no special authority for the pilot not flying to command a go-around, and this is of particular concern when the pilot not flying, is the more junior crew member. It is recommended that operators devise and implement Policies to allow the “Emergency authority” for pilots not in command to take control in emergency situation, should be encouraged and enforced.
Most terrain awareness systems currently available are incompatible with VFR operations in mountainous terrain.
Nuisance’ warnings have the potential to exacerbate CFIT risk. The crew members should be advised not to isolate audio warnings. It is recommended that regulatory authorities and operators interact with system manufacturers to review the warning logic to ensure that the frequency of nuisance warnings is minimized, without unduly compromising the systems terrain awareness and warning capabilities.
‘Nuisance’ warnings can also be inherent in the design of approach procedures, especially those using satellite based guidance to provide instrument approaches in challenging terrain.
Safety Management System (SMS), enhanced CRM, strict adherence to SOPs and result oriented Ground training need continued emphasis.
Unclear approach templates may cause pilots to deviate from them or misinterpret them hence taking them close to unsafe areas especially if the airport is near mountainous regions. This is exacerbated especially if pilots are unfamiliar and are operating into the airport in a night time environment. Operators and pilots must ensure that they carry the most up-to-date flight instrument charts so that they fly the correct instrument charts and do not fly into terrain mistakenly.
An unstable approach also has been found to be a factor contributing to CFIT accidents. Unstable approaches increase the possibility of diverting a flight crew’s attention away from the approach procedure to regain better control of the airplane. Operators must require their pilots to fly a stabilized approach and to always make timely decision to go-around from an unstable approach.
It is evident that most of the CFIT accidents result from a pilot’s breakdown in situational awareness (SA) instead of aircraft malfunction or a fire. SA refers to the accurate perception by flight crew of the factors and conditions currently affecting the safe operation of the aircraft, and their vertical and/or horizontal position awareness in relation to the ground, water, or obstacles. The data shows that 49 percent of CFIT accidents had vertical, lateral or speed deviations as a contributing factor to CFIT accidents.
Situational awareness can be enhanced through proper flight planning, preparation, knowledge about aircraft, systems, on board equipment, procedures, alertness and vigilance particularly during critical phases of the flight and good CRM. More reliable warnings of possible terrain conflicts through EGPWS that is equipped with accurate navigation systems like global positioning system (GPS) for both navigation and terrain surveillance can improve situational awareness.
Flight crew non-compliance with established procedures was a contributing factor in 23 percent of CFIT accidents. Poor CRM was also a frequent contributing factor.
Pilot Performance remains a major factor in CFIT accidents; despite the efforts to mitigate risk, handling and/or inappropriate actions by flight crew continue to be weak area..
Training, whether it is academic or simulator training, should allow pilots to experience realistic situations that require timely decisions and correct responses. Simulator training should also be given to provide pilots the opportunity to practice CFIT prevention strategies, including the escape manoeuvring. Training should be given to pilots during initial, transition and recurrent training.
Data collection and analysis can provide information of threats, hazards and identify potential weaknesses of an operator.
Collection and sharing of flight data in order to identify hazards ahead of time and mitigate those risks that can lead to an accident is another important element for continued improvement in CFIT accidents.
The best potential source of operational data is the operators’ own Flight Data Monitoring (FDM), Flight Data Analysis (FDA), or Flight Operations Quality Assurance (FOQA) programs.
The aim should be to improve safety through an analysis of information downloaded from an aircraft’s on-board computer at the end of every flight. This information can be used to identify trends and discover issues that might develop into a serious safety problem.
The routine download and analysis of recorded flight data has been used by operators for many years as a tool to identify potential hazards in flight operations, evaluate the operational environment, validate operating criteria, set and measure safety performance targets, monitor SOP compliance and measure training effectiveness.
In non-routine circumstances, when an incident occurs the data can be used to debrief the pilots involved and inform management. In a de-identified format the incident data can also be used to reinforce training programs, raising awareness amongst the pilot group as a whole.
Revise the minimum operational performance standards to improve the effectiveness of terrain awareness and warning systems when an airplane is configured for landing and near the airport, including when the airplane is descending at a high rate and there is rising terrain near the airport.
All operators of airplanes equipped with the automated “minimums” alert should brief crew members to activate it.
For those airplanes not equipped with an automated “minimums” alert, it is advised that all operators of airplanes equipped with terrain awareness and warning systems (TAWS) to activate the TAWS 500-ft voice callout or similar alert.
Human, Procedural, Technological. The available human mitigations involve improving and maintaining pilots’ knowledge, their awareness and their competence, and each of these can be achieved by a comprehensive training program embracing classroom, simulator and flight training.
With realistic training, flight crew will be well prepared to:
- Know the hazards of flying close to terrain.
- Recognize the symptoms of spatial disorientation.
- Recognize the factors that may lead to CFIT accidents.
- Know the mitigation strategies that will ensure a safe flight.
The Safety management systems (SMS) must incorporate management procedures to constantly review and assess the CFIT risk exposure to the operation in order to ensure that the risk is as low as reasonably practicable (ALARP) and tolerable.
Technologies have also been developed to mitigate the risk of a CFIT accident. There are a variety of technologies available but the most considerable one is TAWS/EGPWS; this technology can be used with a terrain map database via GPS to provide the pilots with a more reliable source of data.
Unfortunately, many pilots falsely believe that there is sufficient time to react once an EGPWS alert is sounded. In order to be effective, it is essential that the aircraft system hardware and firmware are correctly maintained and that the software database is properly updated.
Vertical situation displays in the cockpit are becoming more common and these provide pilots with an easy to assimilate picture of the terrain profile ahead of the aircraft, together with its projected vertical flight path.
Operators must ensure that the latest modifications are incorporated in their TAWS/EGPWS computer and with GPS providing aircraft position data directly to the computer. These provide earlier warning times and minimize unwanted alerts and warnings.
Furthermore, appropriate TAWS/EGPWS response procedures by the operators should be established for the flight crew in accordance to the aircraft type performance capability. These procedures should include and encourage pilots that “warnings” should be followed without hesitation as soon as a triggered.
DGCA should promote development and use of a low cost terrain clearance and/or a look ahead devices particularly for helicopters who operate at low levels close to the terrain, obstructions.
Supervision and monitoring of flying operations by Accountable Managers, Chief Operations Officers, Chief Pilots of aircraft and helicopters particularly belonging to NSOP, State Govt and Private operator’s needs to be improved.
Effective implementation of SMS which improve Company Safety culture, must be ensured.
The senior management, Accountable Managers, Chief Operating Officers and Chief Pilots must proactively identify hazards related to operations during adverse weather conditions (Pre Monsoon, Summer Season, Monsoon Season, Winter Season) and operations to and from airports, helipads which are known to be difficult and challenging. Standard procedures should be introduced to brief the pilots about the hazards and precautions they need to take to operate safely. Operations Staff and Chief of Flight Safety should be fully involved and remain extra alert and vigilant during marginal weather conditions to provide necessary and accurate weather related information, support and guidance to pilots.