In aviation, the top of descent, also referred to as the TOD or T/D, is the computed transition from the cruise phase of a flight to the descent phase, or the point at which the planned descent to final approach altitude is initiated. The top of descent is usually calculated by an on-board flight management system, and is designed to provide the most economical descent to approach altitude, or to meet some other objective (fastest descent, greatest range, etc.).
The top of descent may be calculated manually as long as distance, air speed, and current altitude are known. This can be done by finding the difference between current altitude and desired altitude, dividing the result by the desired rate of descent, and then multiplying that figure by the quotient of the ground speed (not airspeed) and 60. ((C-T)/RoD)*(KGS/60)=TOD. The result dictates how far from the destination descent must begin.
The basic principles of air navigation are identical to general navigation, which includes the process of planning, recording, and controlling the movement of a craft from one place to another.
Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are indicated airspeed ("IAS"), calibrated airspeed ("CAS"), equivalent airspeed ("EAS"), true airspeed ("TAS"), and density airspeed.
The true airspeed of an aircraft is the speed of the aircraft relative to the airmass in which it is flying. The true airspeed is important information for accurate navigation of an aircraft. Traditionally it is measured using an analogue TAS indicator, but as the Global Positioning System has become available for civilian use, the importance of such analogue instruments has decreased. Since indicated airspeed is a better indicator of power used and lift available, True airspeed is not used for controlling the aircraft during taxiing, takeoff, climb, descent, approach or landing; for these purposes the Indicated airspeed – IAS or KIAS – is used. However, since indicated airspeed only shows true speed through the air at standard sea level pressure and temperature, a TAS meter is necessary for navigation purposes at cruising altitude in less dense air. The IAS meter reads very nearly the TAS at lower altitude and at lower speed. On jet airliners the TAS meter is usually hidden at speeds below 200 knots (370 km/h). Neither provides for accurate speed over the ground, since surface winds or winds aloft are not taken into account.
In aeronautics, a spoiler is a device intended to intentionally reduce the lift component of an airfoil in a controlled way. Most often, spoilers are plates on the top surface of a wing that can be extended upward into the airflow to spoil the streamline flow. By so doing, the spoiler creates a controlled stall over the portion of the wing behind it, greatly reducing the lift of that wing section. Spoilers differ from airbrakes in that airbrakes are designed to increase drag without affecting lift, while spoilers reduce lift as well as increasing drag.
An electronic flight instrument system (EFIS) is a flight deck instrument display system that displays flight data electronically rather than electromechanically. An EFIS normally consists of a primary flight display (PFD), multi-function display (MFD), and an engine indicating and crew alerting system (EICAS) display. Early EFIS models used cathode ray tube (CRT) displays, but liquid crystal displays (LCD) are now more common. The complex electromechanical attitude director indicator (ADI) and horizontal situation indicator (HSI) were the first candidates for replacement by EFIS. Now, however, few flight deck instruments cannot be replaced by an electronic display.
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing or to a point from which a landing may be made visually. These approaches are approved in the European Union by EASA and the respective country authorities and in the United States by the FAA or the United States Department of Defense for the military. The ICAO defines an instrument approach as a series of predetermined maneuvers by reference to flight instruments with specific protection from obstacles from the initial approach fix, or where applicable, from the beginning of a defined arrival route to a point from which a landing can be completed and thereafter, if landing is not completed, to a position at which holding or enroute obstacle clearance criteria apply.
A primary flight display or PFD is a modern aircraft instrument dedicated to flight information. Much like multi-function displays, primary flight displays are built around a Liquid-crystal display or CRT display device. Representations of older six pack or "steam gauge" instruments are combined on one compact display, simplifying pilot workflow and streamlining cockpit layouts.
A flight management system (FMS) is a fundamental component of a modern airliner's avionics. An FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew to the point that modern civilian aircraft no longer carry flight engineers or navigators. A primary function is in-flight management of the flight plan. Using various sensors to determine the aircraft's position, the FMS can guide the aircraft along the flight plan. From the cockpit, the FMS is normally controlled through a Control Display Unit (CDU) which incorporates a small screen and keyboard or touchscreen. The FMS sends the flight plan for display to the Electronic Flight Instrument System (EFIS), Navigation Display (ND), or Multifunction Display (MFD). The FMS can be summarised as being a dual system consisting of the Flight Management Computer (FMC), CDU and a cross talk bus.
In aviation, VNAV is glidepath information provided during an instrument approach, independently of ground-based navigation aids. An onboard navigation system displays a constant rate descent path to minimums. The VNAV path is computed using aircraft performance, approach constraints, weather data, and aircraft weight. The approach path is computed from the top of descent point to the end of descent waypoint, which is typically the runway or missed approach point.
Required navigation performance (RNP) is a type of performance-based navigation (PBN) that allows an aircraft to fly a specific path between two 3D-defined points in space.
An autothrottle is a system that allows a pilot to control the power setting of an aircraft's engines by specifying a desired flight characteristic, rather than manually controlling the fuel flow. The autothrottle can greatly reduce the pilots' work load and help conserve fuel and extend engine life by metering the precise amount of fuel required to attain a specific target indicated air speed, or the assigned power for different phases of flight. A/T and AFDS can work together to fulfill the whole flight plan.
Area navigation is a method of instrument flight rules (IFR) navigation that allows an aircraft to choose any course within a network of navigation beacons, rather than navigate directly to and from the beacons. This can conserve flight distance, reduce congestion, and allow flights into airports without beacons. Area navigation used to be called "random navigation", hence the acronym RNAV.
Armavia Flight 967 was a scheduled international passenger flight operated by Armavia from Zvartnots International Airport, Zvarnots in Armenia to Sochi, a Black Sea coastal resort city in Russia. On 3 May 2006, the aircraft operating the route, an Airbus A320-200, crashed into the sea while attempting to go-around following its first approach to Sochi airport, killing all 113 aboard.
Scandinavian Airlines System Flight 933 was a scheduled international flight from Denmark to the United States that on January 13, 1969, crashed into Santa Monica Bay at 19:21, approximately 6 nautical miles (11 km) west of Los Angeles International Airport (LAX) in California, United States. The crash into the sea was caused by pilot error during approach to runway 07R; the pilots were so occupied with the nose gear light not turning green that they lost their situation awareness and failed to keep track of their altitude. The Scandinavian Airlines System (SAS) aircraft had a crew of nine with 36 passengers, of whom 15 died. The flight originated at Copenhagen Airport, Denmark, and had a stopover at Seattle–Tacoma International Airport, where there was a change of crew. The crash was similar to Eastern Air Lines Flight 401. The crash site was within international waters, but the National Transportation Safety Board carried out an investigation, which was published on July 1, 1970. The report stated the probable cause as improper crew resource management and stated that the aircraft was fully capable of carrying out the approach and landing. The aircraft was conducting an instrument approach, but was following an unauthorized back course approach.
A step climb in aviation is a series of altitude gains that improve fuel economy by moving into thinner air as an aircraft becomes lighter and becomes capable of flying in the thinner air at higher altitude.
A gravity turn or zero-lift turn is a maneuver used in launching a spacecraft into, or descending from, an orbit around a celestial body such as a planet or a moon. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory. It offers two main advantages over a trajectory controlled solely through the vehicle's own thrust. First, the thrust is not used to change the spacecraft's direction, so more of it is used to accelerate the vehicle into orbit. Second, and more importantly, during the initial ascent phase the vehicle can maintain low or even zero angle of attack. This minimizes transverse aerodynamic stress on the launch vehicle, allowing for a lighter launch vehicle.
In aviation, the top of climb, also referred to as the TOC or T/C, is the computed transition from the climb phase of a flight to the cruise phase, the point at which the planned climb to cruise altitude is completed. The top of climb is usually calculated by an on-board flight management system and is designed to provide the most economical climb to cruise altitude or to meet some other objective. The top of climb may be calculated manually with considerable effort.
Iberia Airlines Flight 610 was a scheduled domestic passenger flight from Madrid to Bilbao, Spain. On 19 February 1985, a Boeing 727-200 operating the flight crashed into a television antenna on the summit of Mount Oiz in Biscay near Bilbao. All 141 passengers and 7 crew on board died. The crash is the deadliest aviation disaster in both Basque Country and Iberia history.
This is a list of the acronyms and abbreviations used in avionics.
Aeroflot Flight 2808 was a scheduled domestic passenger flight from Mineralnye Vody to Ivanovo, both in Russia, with a stopover in Donetsk, Ukraine on 27 August 1992. While attempting to land at Ivanovo airport, the Tupolev Tu-134 crashed into a group of buildings in the village of Lebyazhy Lug. Investigators determined the cause of the accident was errors made by the crew and the air traffic controller. There were no fatalities on the ground, but all 84 people on board the flight died in the crash.