Navigation

Question 1

What is INS?

Answer 1

Onboard self-contained inertia navigation system
Provide continuous information on an aircraft’s position without any external assistance.

IRS: modern INS with greater integration into the FMS (provide aircraft’s magnetic position and heading information).

Measures the aircraft’s inertia movement from an initial position and continuously update this position with the aid of accelerometers. (change of acceleration in the horizontal plane)

Question 2

How does INS differ from GPS?

Answer 2

INS: free from external navigation aids and atmospheric errors but has bounded and unbounded
errors.

GPS: 4 satellites need always to be in the line of sight range of the aircraft

Ability to integrate GPS data into the FMS, very accurate but we can have some system errors.

Question 3

What line joins two points on the Earth’s surface by the shortest distance?

Answer 3

A great circle track joins 2 points on the Earth with the shortest distance but constantly changing
track direction as a result of convergence.

Question 4

What is convergence?

Answer 4

Convergence is the change of direction experienced along east-west tracks.

Question 5

What is RNAV?

Answer 5

Onboard area navigation aircraft equipment that uses either VOR/DME system, DME/DME, INS/IRS, or Loran C.

Allows the operator to input the bearing & the distance of a geographic location with reference to a given station to position a waypoint.

Question 6

Define RNP?

Answer 6

Required Navigation Performance

Performance based navigation that allows the
aircraft to fly a specific path between 2-3D points defined in space.

RNAV and RNP are similar.

Question 7

What is RVSM?

Answer 7

Reduced Vertical Separation Minima

Reduction of the standard vertical separation of 2000ft
to 1000ft between flight level 290 and FL410.

This increases the number of aircraft capable to fly
within this altitude range at the same time.

Aircraft has to be equipped with a sensitive pressure altimeter, airline must also receive the approval.

Question 8

What is GPS

Answer 8

GPS constellation consists of a minimum of 24 satellites which 21 are operational at one time.

Sat 1 and 2 : Lat/Long
Sat 3: Confirm lat and long
Sat 4: Altitude

Question 9

Define PBN?

Answer 9

Performance Based Navigation.

Define the operational performances required in airspace, routes, or approach.

• In term of precision, integrity & continuity.
• Navigations sensors
• Crew qualified

RNP: required alert fonction & surveillance of aicraft performance.
RNAV: DO NOT required alert function & surveillance of aircraft performance.