Aviation Norms, Civil Aviation, Flight Safety


Off 8

Winter is already here and with it, the associated flying hazards during Winter Season. Number of accidents/serious incidents has occurred around the world during winter months.

The accident of Air India, Air Bus 320, at Jaipur, on 05 Jan 14, which fortunately did not result in casualties, highlights the need for involvement by all stakeholders to prevent any accident/incidents. There is a need to learn lessons from the investigation reports of such accidents lest history repeats itself.

Since the Air India, Air Bus 320 accident, DGCA in coordination with AAI has taken number of initiatives to prevent any incidents/ accidents during fog conditions at Delhi airport, which is generally worst affected. The ILS at Lucknow and Jaipur has been upgraded to CAT III A .The Operators have been advised by DGCA to have adequate fuel for a diversion to minimum two airports, mainly, Jaipur and Ahmadabad. A close watch is kept by the Air Traffic Management Staff  on weather developments at Delhi and surrounding airports. The inbound traffic  particularly  schedule flights are allowed to take off for Delhi only after evaluation of existing weather and trends. This is a proactive step by DGCA and AAI and must be appreciated.

Aviation Safety Management Society of India which is dedicated to promote Aviation and Aviation Safety and Efficiency of Aviation Operations in the country, wishes to disseminate certain precautions which should be taken by the Operators during winter flying, to prevent any incident/accident.

Hazards Associated During Winter Flying and Precautions to be Taken.

Lack of Visual reference, due Poor Visibility caused by Fog or Low Clouds.

Visual Illusions, Spatial Disorientation and Loss of Situational Awareness.

Western Disturbances associated with Thunderstorms, Wet/contaminated runways.

Icing, Snow blindness/White out.

Fog and low clouds leading to poor visibility conditions are a major flight   safety hazard during winter months particularly in Northern, North Eastern and to some extent in Western parts of India. Hence, it is essential for the Operators/Accountable Executives, Air Crew, Ground Crew and Dispatchers to be fully aware about the phenomenon of fog and the hazards associated with it. Pilots must be fully aware about the timings, extent, duration and severity of fog.

Formation of fog, its thickening and improvement in visibility are quite unpredictable. Although most of the time the Met Forecast is reasonably accurate yet there are many instances when pilots have got caught in very poor visibility conditions, may be due to faulty Met forecast or lack of  intelligent weather  analysis on the part of the Pilots. Hence, it is very important for all Operators and Pilots to keep the hazards of winter flying in mind while planning flying.

The Accountable Executives/Managers should  ensure that all the Pilots have gone through the necessary flying, simulator  and ground training with added emphasis on Low Visibility Operations, as per the DGCA CIVIL AVIATION REQUIREMENT, SECTION 8 – AIRCRAFT OPERATIONS SERIES ‘C’ ,PART I,Issue I, Dated 13th June 2011, Effective, 01 April 2017.

All Weather Operations (AWO), OPERATIONS CIRCULAR 09 of 2017 dated 18 Aug 2017 on Approach and Landing Accident Reduction (ALAR) and Controlled Flight into Terrain (CFIT) reduction tool kit, is a very comprehensive document and all the pilots should be made knowledgeable about it.

All the pilots should be current in instrument flying, should have undergone Poor Visibility Operations Training (LVO) and clearances etc as per DGCA CAR.

Thorough weather briefing must be obtained before undertaking any flying. Briefing from the Met Department and various Weather Sites should be complemented with the experience of having operated in particular area or region. Knowledge of typical weather phenomenon affecting specific areas like Delhi and adjoining areas, during winters is of paramount importance.

Most of the times, the fog thickens at sunrise and may last for long hours before clearing or may not  clear for hours or even days. Whenever, the surface temperature and dew point temperature are very close to each other, adverse weather and dense fog can be expected.

Special precautions need to be taken while flying during Night, Dawn and Dusk. Night flying during winters should be undertaken with extra caution since poor visibility during night flying is a serious hazard. Use of landing lights during approach in foggy conditions should be avoided since it may degrade the visibility and lead to visual illusions and disorientation.

Low clouds may form quickly as the fog lifts and cover large areas, particularly in the hilly regions; they can cover the entire valleys without any gaps for penetration.

Remember Fuel is Life. Hence meticulous Fuel planning and close Monitoring of the fuel state is of great importance since one may be forced to divert due to poor visibility conditions/closer of runway due to some occurrence and most of the time, a diversion may not be easily available, due to widespread fog ,covering hundreds of kilometres.

Thorough planning and preparation for the flight is an inescapable necessity and should not be ignored. Pre Flight briefing for operations during poor visibility conditions should be much more comprehensive and the pilots must plan for contingencies.

A very high level of situational awareness must be achieved related to prevailing weather and its trends, terrain, availability and serviceability of Nav and approach aids and watch  hours of the neighbouring airports, in the vicinity of  the destination airport.

Continuous Monitoring of the weather situation at the destination, with particular emphasis, on visibility and RVR through ATIS, RT and other aircraft in the general area of your route and destination is strongly recommended.

Timely and sound decision making based on the overall situational awareness, should be inculcated among the pilots. Overconfidence and complacency must be kept under check.

Emphasis must be laid on ensuring Stabilised approaches as per the DGCA guidelines and there should be no hesitation on part of the pilots to go around and if required, divert in time.

Chief of Flight Safety, Base Managers and Dispatchers should be knowledgeable, fully involved and vigilant, particularly, during the severe weather phase. They   should keep a close watch on the progress of the flights and keep pilots abreast with latest developments about the weather at the destination airports and neighbouring areas, for possible diversion.

In depth knowledge about the aircraft, systems, procedures, understanding the phenomenon of visual illusions, spatial disorientation, process of recovery from unusual situations, strict adherence to SOP’s and rules, regulations and correct altimeter settings, are key to successful and safe accomplishment of the flights.


While most of the precautions and suggestions enumerated above are equally applicable to helicopters, yet some additional aspects need to be kept in mind.

Helicopters generally fly at low altitudes and ground contact flying is resorted to by most of the pilots. Hence, it is of utmost importance to be fully knowledgeable about the terrain along the route and 20 to 30 miles on either side of the route.

Knowledge about the Minimum Enroute Altitude, Safe Altitude, MORA, Grid MORA is essential.

Know the obstructions in your area of operations. Pylons, Communication/chimney towers, electric/telephone cables, trolley cables particularly in hilly areas pose a major hazard and knowledge of these is important for helicopter pilots.

Adverse weather leading to poor visibility and hilly terrain are a dangerous combination and great caution needs to be exercised during hill flying.

Operations in snow bound areas require special skill levels. Special briefing and training is essential for safe operations in these areas. Snow blindness (white out), blowing snow during pick up, hover and sit down, skids/wheels getting stuck in snow, disorientation and White out are some of the aspects which need to be taken into account for snow bound area operations.

Ice formation above freezing level is a serious hazard. Anti-icing measures like serviceable and available ice detectors, heating elements, need for frequent movement of controls to prevent Jamming of controls due ice formation, knowledge about freezing level and potential of ice formation are some of the areas which require the  attention of the Pilots.

Check and ensure the serviceability of wind screen wipers, pitot heaters. Do not forget to switch on pitot heaters whenever required and switching them off on landing.

Be current in instrument flying and have full knowledge about visual illusions, Spatial Disorientation and Controlled Flight into Terrain.

Tendency to look outside while flying on instruments is dangerous since outside clues and distractions, may cause spatial disorientation.

Always plan for contingencies, have thorough pre flight and weather briefing. Do not hesitate to carry out a precautionary landing at any suitable place if unable to continue the flight due weather or poor visibility (ASC 09/2013).

Take timely decision to either divert or land at suitable place since delayed decision may complicate the situation, leading to compromise on safety or an unfortunate accident.

Accountable Manager, Chief Pilot, Ops Managers should involve themselves to ensure flight following, monitoring of weather and keeping the pilots abreast with the weather developments. They should ensure that the pilots have no pressure on them to undertake the task in the face of adverse weather and poor visibility conditions.

Overconfidence, complacency are to be avoided. Never take chances with the poor weather conditions and don’t be overconfident. Overconfidence has taken the lives of many pilots.

There may be occasions when frustration may set in because of the delays and postponement of departure timings/dates and long wait on ground, due prolonged bad weather spells. Number of  pilots have taken chances with weather under such conditions and have met with serious /fatal accidents. Please be aware of the grave danger, under such conditions and take very considered decisions.


Although efforts have been made to include all the necessary precautions which should be taken during winter flying, yet some important aspects may have been missed out. Operators may like to add other aspects which may be typical to their type and area of operations.

Operators should always endeavour to match the man with the machine, mission and weather conditions. Adequate training in instrument flying, simulator flying, currency, recency in area of operations, Comprehensive briefing covering the entire spectrum of the various aspects of the operations, good CRM, adherence to SOP’s, involvement of Chief  Pilots, Chief of Flight Safety and close monitoring  of the performance of the pilots, are key to the successful  and safe conduct of the operations.

Respecting the weather and courage of conviction to say no if the safety of the flight is likely to be compromised due weather, must be impressed upon the pilots.

ASMSI wishes you all safe and efficient flying operations during winters.

Many Many Happy Landings. 

Air Commodore BS Siwach AVSM YSM VM
Director General
Aviation Safety Management Society of India


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