Navigation (ACS) Flashcards
(Navigation)
What types of navigation are there?
Pilotage: navigation by visual landmarks
Dead reckoning: flying a course between set checkpoints by deriving heading time and distance from winds aloft and magnetic variation.
Radio navigation: using ground based navigational aids to fly your course.
Celestial Navigation: navigation by observation of the positions of celestial bodies, inclusive of the sun, moon, planets and certain stars.
(Navigation)
What makes a good checkpoint?
Something on the ground that is very obvious from the air. Large mountains, big lakes, and other unmistakeable distinct things on the ground.
Checkpoints should be no further than 5-10 miles apart at the start.
During cruise checkpoints can be 10-20 miles apart.
(Navigation)
Can your EFB be your only chart?
Yes. Your electronic flight bag with current documents that mirror the paper ones is fine to be the only reference for charts.
Always have backups though, Ipads and other electronics run out of batteries.
(Navigation)
How does VOR work?
VHF omni direction range (VOR) works by sending out two signals. One is fixed and is called a reference signal the other is a rotating signal called a variable signal. These signals are just sign waves emitted at 30 hertz. The variable signal rotates 360 degrees 30 times a second.
High speed lighthouse is a good analogy.
A radial is the magnetic bearing from the VOR.
(Navigation)
What are the different types of VOR service volumes?
VOR’s with different service volumes are involved with different airspaces.
Service volumes are separated into 3 categories:
-Low altitude: service distance of 40 nautical miles with a services from 1,000’ to 18,000’
-High altitude:
-Terminal altitude:
-VOR low: new band between 5,000’ and 14,500’ AGL that reaches 70 nautical miles instead of only 40 nautical miles.
-VOR high: new band between 5,000’ and 14,500’ AGL that reaches 70 nautical miles instead of only 40 nautical miles.
Note: do more clarifying research for the terms. Explanations need work.
(Navigation)
What is the VOR minimum operational network?
VOR minimum operational network is the guarantee that there will be VOR coverage above 500’ AGL in the contiguous united states. The FAA won’t eliminate all VORs but they are being decommissioned.
(Navigation)
Whats the difference between a VOR, VORDME, and VORTAC?
A standard VOR cannot tell you how far away you are from the transmitter.
VOR with attached Distance Measuring Equipment (DME) provides distance information to aircraft. VORDME has equipment colocated with the VOR that allows aircraft with appropriate equipment to determine the slant distance from the VOR. Slant distance is the distance between your aircraft and the VOR DME if you measured a straight line from your aircraft directly down to the VORDME.
VORTAC is a VOR combined with a tactical air navigation system or TACAN. TACAN’s are used by the military and have some features that civil aircraft cannot use. We can use the DME functionality that a VORTAC has. So for all the differences a VORTAC has it is essentially just a VORDME to civil aircraft.
(Navigation)
What is a VOR test facility?
A VOR test facility (VOT) is a transmitter that sends out a test signal that a pilot can use to check the accuracy of the VOR receiver.
(Navigation)
What are the ways you can check the VOR receivers accuracy?
-VOT (VOR test facility)
-Airborne checkpoint. A spot on the ground that you need to fly over at a specific altitude, usually a prominent landmark. When over the landmark dial in the VOR frequency and select the listed radial. Make sure your receiver is within six degrees of the radial.
-Ground checkpoint. It’s a mashup a VOT and a airborne checkpoint. By taxiing to a specific spot on the airport surface, check the receiver against a specific VOR and radial. This is more accurate so the deviation should only be 4 degrees of the listed radial.
-Dual VOR check. Tune two VOR receivers to the same VOR, center the CDI and compare the OBS setting. If they are within 4 degrees of each other your VORs are accurate.
(Navigation)
Describe the procedures of flying direct to a VOR.
-Make sure to know how a VOR functions
-Know what a radial is.
-How far you can receive one.
-Limitations.
First, dial in the radio frequency on the receiver. The frequency is on the sectional chart. Check to see that you are receiving the correct VOR by listening to the morse code signifier and comparing it to the one on the chart. If you don’t hear the code and you have set up the audio system correctly the VOR may be out of service or unreliable (further information may be in the NOTAMs). Once the VOR is verified, turn the omni bearing selector until the course deviation indicator (horizontal situation indicator) centers with a TO indication. Make sure that the course you just dialed in makes sense and that it is in the direction you expect. Fly the aircraft to the heading the matches the OBS course and keep the needle centered, adjusting to wind as necessary. Make sure your flying toward the arrow and not in the other direction.
(Navigation)
How do we intercept an outbound VOR radial?
As we pass over the VOR the VOR receiver gets unreliable. It can’t tell where you are in reference to the VOR. As you approach the VOR hold the heading. If you want to fly the 90 radial heading outbound from the VOR, wait until the indicator flips from the TO to the FROM.
(Navigation)
How does a GPS work?
There are three segments that make up the GPS:
-The space segment. There are always 24 operating GPS satellites that continuously transmit their location and the time the transmission was sent, as determined by a super accurate atomic clock.
-Control segment. There are ground based monitoring and control stations that keep an eye on the satellites to ensure they are working properly and adjust them accordingly.
-User segment. The GPS receiver in the aircraft. It uses data from the internal database and the data sent from the satellite’s to provide location in three dimensional space and time.
Must connect to 4 satellites in order to get position in space and time
If your GPS has RAIM it will tell you if there are problems with the satellites it is connected to. Needs 5 satellites.
(Navigation)
What is the Wide Area Augmentation System?
WAAS is a system developed by the FAA to improve GPS accuracy. Consists of a ground segment, a space segment, and user segment.
-Ground segment: consists of 38 ground based reference stations and 3 ground based master stations.
-Space segment: consists of 3 satellites in geostationary orbit.
-User segment: WAAS equipped GPS receiver.
Each of the reference stations has GPS receivers fixed in place on the ground. Since each reference station doesn’t move it always knows exactly where it is. The GPS location data received by the reference stations is passed on to one of the three master stations. Since the master stations know the actual positions of the reference stations if there is a discrepancy between that location and the GPS derived location the master station will know that there is some sort of error with at least one of the satellite signals. The master stations are able to determine what is causing the GPS error and how to compensate for it.
WAAS augments the data and beams the ‘fix’ to the 3 geostationary satellites which in turn beam that information to all of the WAAS equipped GPS receivers. Instead of a 5 meter accuracy radius a WAAS equipped GPS has an accuracy of 1 meter.
(Navigation)
Can you use a handheld or tablet GPS as the primary means of navigation?
Technically you don’t need any navigation equipment onboard for VFR flight other than a magnetic compass. Navigation can be done by pilotage and dead reckoning only. However, it is highly recommended to use GPS.
For IFR GPS operations your aircraft needs an official aviation GPS that is accurate and dependable.
For VFR flight there’s nothing stopping you from using a handheld GPS.
Differences between an aviation GPS and a civil GPS:
-Phones and tablets are more susceptible to failure than a built in aviation GPS.
-Handheld GPS devices don’t have RAIM. Which is usually built into Aviation GPS devices. What it does is automatically check that the receiver is getting accurate GPS data or if it is not connecting to enough satellites for accurate positioning.
-Location of the GPS antenna. A certified aviation GPS will have an antenna located outside the plane somewhere on the top of the fuselage.
(Navigation)
What is ADS-B out?
Automatic Dependent Surveillance–Broadcast
Starting january 1st 2020 all aircraft are required to have ADS-B out in certain airspace. ADS-B out is similar to a mode C transponder. ADS-B out does not wait for an interrogation. It always sending out data to receivers on the ground. Since it is not dependant on a radar sweep, it sends out data more frequently (once per second) which gives a more accurate depiction on what is happening in the aircraft. The other thing that makes it better is that it broadcasts your extremely accurate GPS location, altitude, velocity, squak code, registration number, and much more.
A mode C transponder sends ATC a code and pressure altitude and ATC’s secondary radar gives them your position with every sweep.
Transponder is a device that transmits data only when its interrogated. This interrogation is done by ATC’s secondary radar. When the transponder receives this interrogation it sends out the code and pressure altitude to ATC.
