Visual flight rules, VFR ( Visual Flight Rules, VFR ) - a set of aviation rules and instructions providing for crew orientation and maintaining safe intervals by visual observation of the natural horizon line, landmarks on the ground and other aircraft [1] .
The opposite of PVP are instrument flight rules , in the application of which the location, spatial position and flight parameters of the aircraft are determined by the indications of flight and navigation instruments, and safe intervals are maintained at the direction of the air traffic control body dispatcher.
Content
The use of PVP in Russia
PVP Features
When flying according to the rules of visual flights in Russia, the crew performs [1] :
- maintaining the intervals between aircraft by visual observation;
- maintaining the true safe altitude (when flying below the lower echelon ) and avoiding artificial obstacles, observing the terrain located in front;
- maintaining the established route using visual orientation in a complex using navigation aids ;
- continuous listening to the radio frequency of the air traffic control unit (or operating frequency in uncontrolled airspace).
The rules also provide for continued visual discretion of all aircraft crew members.
In-flight PVP conditions
VFRs in Russia are regulated by the Federal Aviation Rules for Flights in the Airspace of the Russian Federation (FAPP) and the Federal Aviation Rules "Preparation and Execution of Flights in Civil Aviation of the Russian Federation" (FAP-128).
VFR flights are carried out in visual meteorological conditions day and night with maximum discretion of the entire aircraft crew (FAPP, paragraph 54).
PVP flight conditions for civil aviation aircraft vary depending on the flight altitude (less than 300 m or 300 m and above).
PVP flight at true altitudes of less than 300 m is carried out with the visibility of the water or the earth's surface, outside the clouds, during the day with visibility of at least 2000 m for aircraft and at least 1000 m for helicopters , at night with visibility of at least 4000 m (FAP-128, Sec. 3.33.1).
PVP flight at true altitudes of 300 m and above is carried out with the visibility of the water or the earth's surface, the vertical distance from the aircraft to the lower boundary of the clouds is at least 150 m and the horizontal distance to the clouds is at least 1000 m, during the day with visibility at least 2000 m , at night with visibility of at least 4000 m (FAP-128, clause 3.33.2).
It is allowed to fly in PVP and above the clouds, as well as between cloud layers.
PVP flight can be carried out above the clouds if: a) the vertical distance from the clouds to the aircraft is not less than 300 m; b) in case of flight between cloud layers, the distance between the layers is not less than 1000 m; c) visibility in flight of at least 5000 m (FAP-128, clause 3.33.3).
With the release in 2009 of FAP-128, there were fewer restrictions on the conditions for performing a PVP flight. The previous regulatory document, issued back in the USSR in 1985 (“Manual on the production of flights in civil aviation”, NPP GA-85), did not allow flights on PVP at night, and at dusk they were allowed only above the 60th parallel. Now, pilots flying PVP are given much greater freedom of action.
PVP conditions for takeoff and landing
When flying according to the Instrument Flight Rules (IFR), operational meteorological minimums are set for takeoff (visibility value) and landing (visibility value and decision altitude) for each aerodrome for different classes of aircraft. For example, the meteorological minimum for take-off along the IFR may be 200 m (with visibility less than 200 m, take-off is prohibited), and the meteorological minimum for landing is visibility on a strip of 550 m and the decision height is 60 m (the so-called ICAO category I minimum, which means if visibility is on the strip less than 550 m or if the pilot did not see the strip at an altitude of 60 m, landing is prohibited, the aircraft must go to the second circle or alternate aerodrome).
Even aeronautical experts often confuse concepts such as PVP approach and visual approach. Despite the presence of the word “visual” in both terms, these are completely different things. A visual approach is made by an aircraft flying on the IFR (on instruments) in the event that the pilot has visually discovered the airfield, and the dispatcher has allowed the visual approach to be completed. The specific values of the meteorological minimum for a visual approach may not be set, because everything is decided according to the situation - if there is no visual contact with the strip, then there is no question of performing a visual approach.
However, at many airports (in particular, in Russia and the CIS countries) there are meteorological minimums for visual approach, which are calculated using special methods depending on the presence of artificial (TV towers, masts, tall buildings, etc.) and natural (elevations) obstacles near the airfield, the speed of the aircraft landing. Typical values are as follows:
- visual approach for class 4 aircraft ( An-2 and the like) and helicopters of all types - visibility 2,000 - 3,000 m, height of the lower boundary of the clouds 150 - 300 m;
- visual approach for aircraft of class 1, 2, 3 ( An-24 and increasingly heavier) - visibility 5000 m, the height of the lower boundary of the clouds 600 m.
It should be understood that when a visual approach approaching an aircraft operating on IFR, the pilot does not switch to PVP (such an erroneous opinion exists). This means that despite piloting along visual guidelines, the air traffic controller continues to provide safe intervals between the aircraft performing a visual approach and other aircraft. This is the main difference between a visual approach and a PVP approach. When approaching by VFR, as in general when flying by VFR, safe intervals with other aircraft are provided by the pilots of aircraft performing VFR.
See also
- Instrument Flight Rules