May 11, 2022
Whether you are a student pilot getting ready to log your first cross country flight or interested in learning to fly, getting the hang of cross country navigation basics is an essential part of your training. Read on for some insight and tips that will set you up for the basics of cross country navigation.
What Is Cross-Country Navigation?
Cross-country flying is a type of distance flying which is considered to be travelling between two different points (take-off and landing locations) using navigational techniques. This includes planning, recording, and controlling the movement of the aircraft.
Why Is The Correct Navigation Of Aircraft So Important?
Successful navigation while in the air involves careful piloting of the aircraft. This means being able to travel from place to place without getting lost while following all airspace rules and regulations, acting within aviation laws and not endangering the safety of those on board or on the ground.
Air navigation isn’t as simple as navigating your way around when on the ground. Aircraft do not follow roads, they cannot stop midway to figure out which way to go, they carry a limited amount of fuel that cannot be replenished mid-flight, and they travel at high speeds.
If an aircraft is not in the position the pilot thinks it is, this can lead to veering off course and encountering mid-air collisions with other aircraft, collisions with obstructions such as mountains or running out of fuel and having to undertake a forced landing. When flying, most collisions are fatal. It is imperative that constant awareness of position is maintained throughout the flight.
Aviation Navigation Techniques
The navigational techniques used for cross country flying will depend on whether the aircraft is flying under visual flight rules (VFR) or instrument flight rules (IFR). For IFR cross country flights, the pilot will rely on the instruments in the cockpit (such as GPS), and radio navigation aids like the use of beacons to direct the aircraft along the desired path to its destination.
Dead Reckoning (DR) Navigation
Dead Reckoning (‘ded’, meaning deduced Reckoning) is another basic navigation technique. Dead Reckoning is based on a series of mathematical calculations used to plot a course, this method is heavily based on previously known positions for accuracy. Calculations are made on flight time, airspeed, distance and direction (heading), as well as factoring in the effects of wind, air density, and aircraft weight and power settings.
Dead Reckoning comes from an old maritime concept that involves using a known initial position, the speed and direction of travel, and the length of time that speed and direction has been maintained to determine the new position. A course is plotted on charts, adding fixed position checkpoints to break up the distance. Visual observations are noted, and ground features are used to confirm checkpoints and therefore confirm the estimated position.
There are three primary aircraft instruments essential for DR navigation during flight, the Bearing Distance Heading Indicator (BDHI) for direction and position, a clock for time and an Airspeed Indicator for tracking the speed of the aircraft. It is also necessary to have an altimeter and outside air temperature gauge, which provide altitude and temperature information used to calculate the effects of the air’s density which can have an effect on the true airspeed.
Although Dead Reckoning is not used as much in practice today due to the wider use of electronic navigational aids, the principles involved are still an important skill for pilots to learn. DR is taught in Flight Training Schools worldwide, and mastering the skill is necessary to pass your flight school theory and cross country flying practice.
One of the major drawbacks of Dead Reckoning is that it is subject to cumulative errors. In order to remain accurate, precise measurements of speed and direction must be known at all times.
Electronic Navigation Aids
The advent of electronic navigational aids has allowed pilots to rely less on the traditional methods outlined above and more on the computational abilities of radio navigation and, more recently satellite navigational systems.
This means IFR rated pilots are able to fly under Instrument Flight Rules or, in other words, by relying on the aircraft’s instruments to gain directional headings (flying without visuals). Known as NAVAIDS, electronic navigation encompasses several different elements, namely; ADF/NDB, VOR, ILS, GPS, DME and INS.
- Automatic Direction Finder and Nondirectional Radio Beacon (ADF/NDB). One of the first electronic navigation systems available, the ADF/NDB combo relies upon a non-directional beacon (NDB) that sends a signal to the aircraft where an instrument known as the Automatic Direction Finder (ADF) depicts where the aircraft is located in relation to the beacon on the ground. The pilot then uses this information to navigate towards the beacon, effectively beacon-hoping their way to their destination. The ADF/NDB system of navigation is somewhat outdated and prone to errors particularly in situations where there is interference of the radio signal or line of sight cannot be maintained.
- VOR or VHR Omnidirectional Range. A radio-based NAVAID that operates in a very high-frequency band range, VOR’s are located on the ground, transmitting two radio signals. One continuous 360-degree reference signal and another sweeping directional signal. The aircrafts Omni-Bearing Indicator (OBI) or Horizontal Situation Indicator (HIS) interprets this information and displays which radial from the VOR the aircraft is located on and which direction the aircraft is flying in relation to the VOR. The VOR system is one of the most commonly used NAVAIDS in the world of aviation and is often used as a backup to the more modern GPS system.
- Instrument Landing System (ILS). ILS are one of the most accurate aircraft approach systems available. These approach based systems are used to guide aircraft down to the runway in preparation for landing. The ILS uses horizontal and vertical radio signals emitted from the runway that intercept each other to give the pilot precise location information on the ideal angle or glideslope for decent.
- Global Positions System (GPS). The most commonly used navigational aid for pilots today, GPS are highly accurate and operational in real-time. GPS depend on multiple satellites to calculate the precise position of the aircraft and offer guidance along its intended flight path as well as calculating its speed. GPS are not infallible, however they are the most reliable navigational aids to date.
- Distance Measuring Equipment (DME). DME uses a transponder in the aircraft to determine the time it takes for a signal to travel to and from a DME station located on the ground. DME stations transmit/receive on UHF frequencies and compute the distance for the pilot in tenths of a nautical mile.
- Inertial Navigation Systems (INS). An INS is a high-speed computer that calculates the same Dead Reckoning information that the pilot does – but much faster and with greater accuracy.
5 Tips To Remember When Planning A Cross Country Flight
1. Choose Your Route Carefully
In NZ, for the most part, choosing your destinations is likely based on airports and the opportunity to refuel. However, you will need to take into account weather conditions, lesson requirements, and experience in different airspace environments (controlled/uncontrolled). It is also necessary to consider any obstructive terrain such as mountain ranges or large bodies of water, military operational areas or any temporary flight restricted zones. Look for checkpoints that are easy to identify, such as lakes, rivers, towns and other prominent ground features.
2. Get An Up To Date Weather Briefing From A Reputable Source
Up to date weather information is vital to the success of any VFR cross country flight. There are a number of official ways to get aviation weather information in NZ, the CAA recommends the following:
3. Decide On Optimum Altitude and Optimum Cruise Settings
The altitude limits are usually determined by the performance capabilities of the aircraft you are flying and the terrain and obstacles you are covering, some consideration must also be given to the ability to find appropriate checkpoints from the air as well. The aircraft’s performance charts in the manual can help you determine the optimal altitude and cruise power to get the best range from your flight.
4. Familiarise Yourself With Airport Procedures
If you have never landed at the destination airport, you must familiarise yourself with its layout, runways, taxi instructions and hours of operation. Making sure fuel is available is imperative if you wish to make your way home, and you’ll probably want to use the toilet! It is also important to research controlled airspace protocols such as entry and exit procedures, transit and exit lanes, even if you are just passing by.
5. Be Prepared For The Unexpected
All the planning in the world doesn’t mean you won’t encounter the unexpected. This could be as simple as stronger winds than calculated for, or more complex issues such as instrument failures. Always plan for the unexpected, and you will be ready for anything!