VMC minima and the VFR envelope
A VFR flight needs both adequate flight visibility and the required clearance from cloud. The applicable minimum depends on airspace class, level and, in the lowest band, whether the aircraft can remain clear of cloud with the surface in sight.
Visual meteorological conditions
| Level and airspace | Flight visibility | Distance from cloud |
|---|---|---|
| At or above 10,000 ft AMSL, Classes A to G | 8 km | 1,500 m horizontally and 300 m, or 1,000 ft, vertically |
| Below 10,000 ft but above 3,000 ft AMSL or 1,000 ft above terrain, whichever is higher, Classes A to G | 5 km | 1,500 m horizontally and 300 m, or 1,000 ft, vertically |
| At or below 3,000 ft AMSL or 1,000 ft above terrain, whichever is higher, Classes A to E | 5 km | 1,500 m horizontally and 300 m, or 1,000 ft, vertically |
| Same lowest band, Classes F and G | 5 km | Clear of cloud and with the surface in sight |
Where the competent authority has prescribed it, lower visibility may be allowed in Classes F and G for aircraft flown slowly enough to see other traffic or obstacles in time to avoid collision, or where the probability of encountering traffic is normally low. Bali records the Indian lower limits as 3,000 m for aeroplanes and 1,000 m for helicopters under the applicable authorisation and operating conditions.
The VFR shall not list
- Do not operate VFR above FL 150 unless specifically authorised.
- Do not operate at transonic or supersonic speeds under VFR.
- Do not operate VFR more than 100 NM seaward within controlled airspace.
- Above FL 290, VFR is permitted only where 1,000 ft vertical separation is applied and the operation is approved.
- Do not take off or land at an aerodrome within a control zone, enter its traffic zone or join its traffic pattern when ceiling is below 1,500 ft or ground visibility below 5 km unless an ATC clearance has been obtained.
Time and minimum height
Bali states the Indian VFR period as from 20 minutes before sunrise until 20 minutes after sunset unless the appropriate authority has permitted a local or training exception. Except for take-off, landing or authorised operations, a VFR flight remains at least 1,000 ft above the highest obstacle within 600 m over a congested area or open-air assembly, and at least 500 ft above ground or water elsewhere.
VFR, Special VFR and changing flight rules
VFR is a complete operating rule set, not simply flight outside cloud. Special VFR is a controlled-zone clearance for a particular operation below normal VMC minima, with responsibility and qualification conditions that remain with the pilot.
VFR compliance
A VFR flight in Classes B, C and D airspace, when forming part of aerodrome traffic at a controlled aerodrome, or when operating as Special VFR, complies with ATC clearances and maintains two-way communication as required. Above 3,000 ft AMSL or 1,000 ft above terrain, whichever is higher, VFR cruising level is selected from the direction-based table unless ATC authorises otherwise.
Special VFR
| Element | DGCA study rule |
|---|---|
| Where | Within a control zone, when traffic permits and ATC has issued an individual clearance. |
| Request | Normally requested by the pilot. The operation is identified as Special VFR in the flight-plan other-information field or by radio when no flight plan has been filed. |
| Weather | Ground visibility must normally be at least 1,500 m. Performance Class I or II helicopters may be authorised at 1,000 m. |
| Pilot | The pilot remains responsible for avoiding obstacles and must hold the required instrument, assistant instructor or flight instructor rating stated by Bali. |
| Flight conduct | Remain clear of cloud, in sight of the surface and within the issued ATC clearance. |
Changing from VFR to IFR
A pilot who wishes to change from VFR to IFR submits the necessary changes to the current flight plan or, when in controlled airspace, obtains clearance before proceeding IFR. The clearance must be understood and read back where required.
Changing from IFR to VFR
An IFR flight does not cancel IFR merely because it encounters visual conditions. The pilot uses an explicit message cancelling the IFR flight and communicates the changes to the current flight plan. Cancellation is appropriate only when the flight is intended to continue for a reasonable period in uninterrupted visual conditions.
Flight plans from submission to closure
A flight plan supplies ATS with the information needed to control, advise, coordinate, alert and search for an aircraft. It must represent the planned operation accurately, then be updated whenever a significant change occurs.
When a flight plan is required
- For any flight or portion of a flight to be provided with air traffic control service.
- For IFR flight within advisory airspace.
- For flight within or into designated areas, or along designated routes, when required to facilitate flight information, alerting and search and rescue.
- For flight within or into designated areas, or along designated routes, when required for coordination with military units or adjacent States and to avoid possible interception.
- For every flight across an international border.
Bali states that intended flights in Indian airspace are notified to ATS, except nano and micro remotely piloted aircraft flown within their stated low-level uncontrolled-airspace or enclosed-premises limits. Where RNP, RVSM, RCP or RSP capability is declared, the operator must ensure that the aircraft and operation hold the required approval.
Submission and delay
| Event | Requirement stated by Bali |
|---|---|
| Normal intended flight | Submit at least 180 minutes before estimated off-block time, but not earlier than 120 hours before it. |
| Remotely piloted aircraft operation | Submit at least 24 hours before estimated departure time. |
| Delay | A delay of 15 minutes or more requires a revised estimated departure time, an amendment or a new flight plan as applicable. |
| Time system | Use coordinated universal time in four figures. Clocks used by ATS and pilots should be checked to the required accuracy. |
Contents
The flight plan identifies the aircraft and flight rules, type of flight, number and type of aircraft, wake-turbulence category, equipment and capability, departure aerodrome and time, cruising speed and level, route, destination and total estimated elapsed time, alternate aerodromes, fuel endurance, persons on board, emergency and survival equipment and other relevant information. Items are completed through the alternate-aerodrome entry for the whole route or the portion for which the plan is submitted.
Changes
All changes to an IFR flight plan or a controlled VFR flight plan are reported as soon as practicable. Significant changes to other VFR plans are also reported. An inaccurate fuel endurance or persons-on-board entry discovered before departure is a significant change. An aircraft off track adjusts its heading promptly to regain track. A sustained true-airspeed change of Mach 0.02 or 10 kt, and an estimated-time change greater than two minutes unless another value is prescribed, are reported.
Closing a flight plan
An arrival report is made as soon as possible after landing to the appropriate ATS unit, in person, by radio or by data link. It closes the whole flight plan or the remaining portion to destination. Where inadequate communication may prevent the report, the pilot arranges a reliable alternative before departure.
IFR equipment, levels, reporting and communication
IFR protects flight when outside visual-reference rules by combining suitable aircraft equipment, obstacle-clearance levels, organised cruising levels, reporting and continuous communication.
Aircraft equipment
An IFR aircraft carries suitable instruments and navigation equipment appropriate to the route and the operation. The declared navigation and communication capability must be available, serviceable and approved where the route requires a specific performance.
Minimum levels
| Terrain | IFR minimum where no higher State minimum is established |
|---|---|
| High terrain or mountainous area | At least 2,000 ft above the highest obstacle within 8 km of estimated position. |
| Elsewhere | At least 1,000 ft above the highest obstacle within 8 km of estimated position. |
These values do not authorise descent below a published route, procedure or ATC minimum. The most restrictive applicable minimum governs.
IFR within controlled airspace
An IFR flight complies with ATC clearance, uses the cruising levels prescribed for the route or assigned by ATC, and maintains the required communication and reports. Cruise-climb operations use the appropriate published or assigned band. A change in level is requested and clearance obtained before leaving an assigned level, except where immediate safety action is necessary.
IFR outside controlled airspace
The flight selects a cruising level from the applicable direction-based table and maintains an air-ground voice communication watch on the appropriate frequency where required. Position reports are made at designated reporting points or intervals.
Position reports and controlled-flight changes
A position report identifies the aircraft, position, time, level, next position with estimated time and the ensuing significant point, unless ATS has prescribed a reduced report. A controlled flight reports route deviation, level change, significant speed change and revised estimate promptly. When visual conditions deteriorate during a VFR controlled flight, the pilot requests an amended clearance that permits continued VMC, requests Special VFR if appropriate, or requests IFR clearance.
Communication watch
A controlled flight maintains continuous listening watch and establishes two-way communication with the appropriate ATC unit. SELCAL satisfies the listening-watch requirement when prescribed, but a data-link connection does not remove a required voice watch. In visual conditions after a complete communication failure, continue in VMC, land at the nearest suitable aerodrome and report arrival as soon as possible. Detailed radio-failure procedure is treated in the communications subject.
Distress, urgency, air defence and unlawful interference
Emergency and security procedures aim to make the aircraft unmistakable, preserve communication and keep the flight predictable. Distress indicates grave and imminent danger requiring immediate assistance; urgency concerns safety but does not yet require immediate assistance.
Distress and urgency signals
| Condition | Radio or data signal | Visual signal |
|---|---|---|
| Distress | SOS by radiotelegraphy, MAYDAY by radiotelephony, or the appropriate distress data-link message | Red rockets or shells fired singly at short intervals, or a red parachute flare |
| Urgency concerning aircraft safety | XXX by radiotelegraphy, PAN PAN by radiotelephony, or the appropriate urgency data-link message | Repeated switching on and off of landing or navigation lights when the aircraft is compelled to land but does not require immediate assistance |
Air Defence Identification Zones
Bali identifies North, South, East, West, Central and Southeast sub-zones in the Indian Air Defence Identification Zone structure. A flight entering or operating in an ADIZ follows the notified flight-plan, air-defence clearance, reporting and communication procedures. Air defence clearance validity and revised-time handling depend on the operation type and the applicable notice.
Unlawful interference
The pilot-in-command attempts to continue on the assigned track and at the assigned cruising level until able to notify ATS or until within radar or ADS-B coverage. When forced away from the assigned track or level without radio contact, the pilot broadcasts warnings on the VHF channel in use, the emergency frequency and other appropriate channels when circumstances permit, and uses the transponder and data link when advantageous.
The pilot follows any applicable in-flight contingency procedure. If none is established, the aircraft proceeds at a level that differs from the normally used IFR cruising level by 500 ft where a 1,000 ft vertical minimum is applied, or by 1,000 ft where a 2,000 ft vertical minimum is applied.
Initial interception actions
An intercepted aircraft immediately follows the intercepting aircraft's visual instructions, notifies ATS if possible, attempts radio contact with the interceptor or the controlling unit on 121.5 MHz and, if necessary, 243 MHz, giving identity, position and nature of flight. It selects Mode A code 7700 and the emergency mode on ADS-B unless otherwise instructed. If radio and visual instructions conflict, seek clarification while continuing to comply with the visual signals.
| Interceptor phrase | Meaning | Intercepted-aircraft reply |
|---|---|---|
| CALL SIGN | What is your call sign? | CALL SIGN followed by identity |
| FOLLOW | Follow me | WILCO or CANNOT |
| DESCEND | Descend for landing | WILCO or CANNOT |
| YOU LAND | Land at this aerodrome | WILCO or CANNOT |
| PROCEED | You may proceed | WILCO |
| REPEAT | Repeat your instruction | The interceptor repeats the instruction |
| AM LOST, MAYDAY, HIJACK or LAND | States the intercepted aircraft's condition or intended landing place | The interceptor responds with the appropriate instruction |
Interception signals and pilot response
Interception uses deliberately conspicuous geometry, lights and aircraft configuration. The intercepted pilot responds promptly so the interceptor can see that the instruction has been understood.
| Series | Signal by intercepting aircraft | Meaning and response |
|---|---|---|
| 1 | Positions normally left, slightly above and ahead, rocks wings and flashes navigation lights, then makes a slow level turn onto the required heading. | You have been intercepted, follow me. The intercepted aircraft rocks wings, flashes navigation lights and follows. |
| 2 | Makes an abrupt climbing turn of 90 degrees or more away from the intercepted aircraft without crossing its line of flight. | You may proceed. The intercepted aircraft rocks wings. |
| 3 | Lowers landing gear, shows steady landing lights and overflies the runway or helicopter landing area in use. | Land at this aerodrome. The intercepted aircraft lowers gear, displays steady landing lights, follows and lands if safe. |
| 4 | Intercepted aircraft raises gear and flashes landing lights while passing over the runway at 1,000 to 2,000 ft, or a helicopter circles at 170 to 330 ft, and continues to circle. | Aerodrome inadequate. The interceptor either repeats the landing instruction using the alternate aerodrome procedure or gives the proceed signal. |
| 5 | Intercepted aircraft regularly switches all available lights on and off. | Cannot comply. |
| 6 | Intercepted aircraft irregularly flashes all available lights. | In distress. |
At night, the wing-rocking visual signals include irregular flashing of all available lights so that the signal remains unmistakable. The interceptor avoids manoeuvres that could endanger the intercepted aircraft and considers performance differences when selecting the interception pattern.
Restricted-area warning
A series of projectiles discharged from the ground at 10-second intervals, each showing red and green lights or stars, warns an unauthorised aircraft that it is flying in or is about to enter a prohibited, restricted or danger area. The pilot takes immediate remedial action.
ATC lights, pyrotechnics and ground visual signals
When voice communication is unavailable, the control tower uses coloured lights to issue simple instructions. The signal area uses fixed shapes to communicate runway, traffic and aerodrome conditions.
Control-tower light and pyrotechnic signals
| Signal | Aircraft in flight | Aircraft on the ground |
|---|---|---|
| Steady green | Cleared to land | Cleared for take-off |
| Steady red | Give way to other aircraft and continue circling | Stop |
| Green flashes | Return for landing, with landing clearance to follow | Cleared to taxi |
| Red flashes | Aerodrome unsafe, do not land | Taxi clear of the landing area in use |
| White flashes | Land at this aerodrome and proceed to the apron, with landing and taxi clearance to follow | Return to the starting point on the aerodrome |
| Red pyrotechnic | Notwithstanding previous instructions, do not land for the time being | Not applicable |
An aircraft in flight acknowledges by rocking its wings by day, except on base and final, and by flashing landing lights twice by night or, if not fitted, navigation lights twice. On the ground, acknowledgement is by moving ailerons or rudder by day and flashing landing or navigation lights twice by night.
Ground signals displayed in the signal area
| Ground symbol | Meaning |
|---|---|
| Red square with two yellow diagonals | Landing prohibited and the prohibition may be prolonged. |
| Red square with one yellow diagonal | Because of bad state of the manoeuvring area or another reason, special precautions are required when approaching or landing. |
| White dumbbell | Landing, take-off and taxiing are confined to runways and taxiways. |
| White dumbbell with a black bar across each circular portion | Landing and take-off are confined to runways, but other manoeuvres need not be confined to runways and taxiways. |
| White or yellow crosses | Portion of runway or taxiway marked by crosses is unfit for aircraft movement. |
| White or orange landing T | Direction to use for landing and take-off is parallel to the shaft toward the cross arm. |
| Vertical two-digit number | Direction for take-off, in tens of degrees to the nearest ten degrees magnetic. |
| Right-facing arrow of conspicuous colour | Turns are to be made to the right before landing and after take-off. |
| Black C on yellow background | Location of the air traffic services reporting office. |
| Double white cross | Gliders are operating and glider flights are being performed. |
Marshalling, emergency hand signals and night lights
Marshalling converts aircraft movement instructions into standard body and wand patterns. The pilot obeys the identified signalman, keeps the aircraft under control and stops whenever a signal is unclear or safety is doubtful.
Marshaller to aircraft signals
| Signal | Essential movement or meaning |
|---|---|
| Wingwalker or guide | Raises right hand above head with wand upward and points the left wand down toward the body. |
| Identify gate | Raises fully extended arms straight above the head with wands pointing upward. |
| Proceed to next signalman | Points both arms upward, then moves and extends them outward toward the next signalman or taxi area. |
| Move straight ahead | Bends extended arms at the elbows and moves wands up and down from chest to head. |
| Turn left or right | One arm remains extended while the opposite hand makes the come-ahead motion. Direction is from the pilot's viewpoint. |
| Normal stop | Extends arms and wands at 90 degrees and slowly moves them above the head until the wands cross. |
| Emergency stop | Abruptly extends arms and wands above the head and crosses them. |
| Set brakes | Raises hand just above shoulder with open palm, then closes the fist after eye contact. |
| Release brakes | Raises a closed fist just above shoulder, then opens the hand after eye contact. |
| Insert or remove chocks | Wands move inward toward each other for insert and outward for remove. The signal requires acknowledgement. |
| Start engines | Raises the right arm to head level with wand pointing up and makes a circular motion, while the left arm indicates the engine. |
| Cut engines | Draws wand across the throat in a slicing motion. |
| Slow down | Moves extended arms downward in a patting motion. |
| Slow down indicated engine | Points both wands down and moves the appropriate wand up and down. |
| Move back | Rotates forearms forward. Faster motion requests faster reverse movement. |
| Tail to starboard or port while backing | One arm remains down while the other repeatedly moves from vertical toward horizontal, viewed from the pilot's position. |
| Affirmative or all clear | Raises right arm to head level with wand pointing up, or gives a thumbs-up. |
| Hover | Extends arms and wands horizontally at 90 degrees. |
| Move upward or downward | Moves wands upward or downward with speed indicating required rate. |
| Move horizontally | Extends one arm to the movement side while the other sweeps repeatedly in that direction. |
| Land | Crosses arms with wands downward in front of the body. |
| Hold position | Fully extends arms and wands downward at 45 degrees and holds until clear for another manoeuvre. |
| Dispatch aircraft | Performs a standard salute and maintains eye contact until the aircraft begins to taxi. |
| Do not touch controls | Raises right hand above head, closes fist or holds wand horizontal, with left arm down. |
| Connect or disconnect ground power | Forms a T above the head and then moves the vertical hand toward or away from the horizontal hand. |
| Negative | Holds right arm straight out at 90 degrees and points wand down, or gives a thumbs-down. |
| Establish interphone | Extends both arms at 90 degrees and moves hands to cup both ears. |
| Open or close stairs | Moves one arm in the direction that represents extending or retracting the stairs. |
Emergency hand signals
| Rescue and fire-fighting signal | Meaning |
|---|---|
| Recommend evacuation | Arm extended from body and moved backward, with the other arm held against the body, directing evacuation. |
| Recommend stop | Arms held overhead and crossed at the wrists. |
| Emergency contained | Arms extended outward and down at 45 degrees. |
| Fire | Right hand makes a fanning motion from shoulder to knee while left hand points to the fire area. |
Pilot-to-signalman acknowledgement includes brakes engaged or released and requests to insert or remove chocks. The flight crew does not assume a ground action is complete until the relevant acknowledgement has been exchanged.
Navigation lights and right-of-way at night
An aeroplane displays a red port light through 110 degrees, a green starboard light through 110 degrees and a white rear light through 140 degrees. A steady red light means the other aircraft is on the observer's right and the observer must give way. A steady green light means the observer normally has right-of-way. Red and green together indicate an approaching aircraft. White alone indicates an aircraft moving away.
Red and white together show the other aircraft moving from right to left. Green and white together show movement from left to right. Anti-collision lights are displayed when so equipped, and navigation-light use follows the night and movement rules taught with the general lighting requirements.