FEAST Spatial Orientation and Visualization 2 — Questions and Answers
Question 1: An aircraft is at FL120, flying heading 180 (south) toward a mountainous area. The highest terrain ahead is 9,500 ft. The aircraft has minimum obstacle clearance requirement of 1,000 ft. The minimum safe altitude for this aircraft on heading 180 in this area is:
- 10,500 ft (FL105 approximately) — terrain 9,500 ft + 1,000 ft required clearance (Correct answer)
- 9,500 ft — the aircraft only needs to be above terrain height
- 10,000 ft — standard safe altitude rounded to the nearest 1,000 ft
- 12,000 ft — the current altitude and it should not descend
Correct answer: 10,500 ft (FL105 approximately) — terrain 9,500 ft + 1,000 ft required clearance
Minimum safe altitude = highest terrain + required obstacle clearance = 9,500 + 1,000 = 10,500 ft.
Minimum obstacle clearance altitude (MOCA) or minimum safe altitude requires adding the required clearance (typically 1,000 ft IFR, 2,000 ft over mountainous terrain) to the highest terrain or obstacle in the area. 9,500 + 1,000 = 10,500 ft. The aircraft at FL120 (12,000 ft) currently has 2,500 ft of clearance — well above minimum. But if cleared to descend to 10,000 ft, it would be only 500 ft above terrain — below the minimum. FEAST spatial visualization includes terrain clearance calculation because controllers must visualise 3D terrain and aircraft position simultaneously.
Question 2: Imagine a 3D radar display showing an aircraft at coordinates East 3, North 5, Altitude 8 (in arbitrary units). The aircraft moves: +2 East, -1 North, +2 Altitude. What are its new coordinates?
- East 5, North 4, Altitude 10 (Correct answer)
- East 5, North 6, Altitude 10
- East 1, North 4, Altitude 10
- East 5, North 4, Altitude 6
Correct answer: East 5, North 4, Altitude 10
East: 3+2=5. North: 5+(-1)=4. Altitude: 8+2=10. New position: East 5, North 4, Altitude 10.
3D positional reasoning requires applying independent changes to three coordinates simultaneously. East 3 + 2 = East 5. North 5 + (-1) = North 4 (moved south 1 unit). Altitude 8 + 2 = Altitude 10 (climbed 2 units). All three must be calculated without error. In ATC, controllers constantly update mental 3D aircraft positions as heading, altitude, and position change simultaneously. FEAST 3D spatial visualisation tests assess this multi-axis position tracking ability.
Question 3: On a plan view (top-down) radar display, an aircraft appears to be moving from lower-right to upper-left. On a north-up display, this corresponds to a heading of approximately:
- 315 degrees (northwest) — lower-right to upper-left on a north-up display is northwest (Correct answer)
- 045 degrees (northeast) — upper-left to lower-right reversed
- 225 degrees (southwest) — the aircraft is going toward the lower left
- 135 degrees (southeast) — right to left at an angle is southeast
Correct answer: 315 degrees (northwest) — lower-right to upper-left on a north-up display is northwest
On a north-up radar, lower-right = southeast, upper-left = northwest. Movement from southeast toward northwest = heading 315 (northwest).
On a north-up radar display: up = north (000), right = east (090), down = south (180), left = west (270). Lower-right is the southeast corner. Upper-left is the northwest corner. Movement from lower-right to upper-left is movement from SE toward NW, which is heading 315 degrees (northwest). FEAST spatial orientation tests frequently use radar display movement descriptions without explicit compass labels, requiring candidates to apply north-up conventions to interpret track directions.
Question 4: An aircraft is in a 30-degree banked turn. Compared to a level coordinated flight, the vertical component of lift in this turn is:
- Reduced — in a banked turn, lift is tilted sideways, reducing its vertical component (Correct answer)
- Unchanged — the total lift produced by the wings remains constant
- Increased — the aircraft generates extra lift to prevent altitude loss in the turn
- Zero — all lift becomes horizontal during a banked turn
Correct answer: Reduced — in a banked turn, lift is tilted sideways, reducing its vertical component
In a banked turn, the lift vector tilts with the bank angle. The vertical component decreases (cos 30° = 0.866), while horizontal lift provides centripetal force.
Total lift acts perpendicular to the wing surface. In a banked turn, this vector tilts with the aircraft bank angle. The vertical component = Total Lift × cos(bank angle). At 30° bank, vertical lift = cos(30°) = 0.866 = 86.6% of total lift. The remaining ~13.4% acts horizontally, providing centripetal force for the turn. The reduction in vertical lift means the aircraft would descend unless back pressure is applied to increase angle of attack (and total lift). This spatial physics reasoning is relevant for controllers understanding why turning aircraft may experience altitude deviations.
Question 5: A holding pattern entry for an aircraft arriving from the southwest (heading 045, inbound to the hold fix) with right-hand turns is most correctly described as a:
- Parallel entry — the aircraft first flies outbound parallel to the holding course (Correct answer)
- Direct entry — the aircraft turns immediately to the inbound course
- Teardrop entry — the aircraft flies a tear-shaped path to enter from the protected side
- Offset entry — the aircraft flies offset from the holding fix to join later
Correct answer: Parallel entry — the aircraft first flies outbound parallel to the holding course
An aircraft arriving from the southwest heading 045 needs a parallel entry for a right-hand hold with inbound 090, as it arrives from the non-holding side requiring the parallel entry procedure.
ICAO holding entry procedures divide the airspace around a holding fix into three sectors: direct entry (sector 1), teardrop entry (sector 2), and parallel entry (sector 3). Arrival from the southwest on heading 045 with a right-hand hold and inbound 090 places the aircraft in the parallel entry sector. The parallel entry involves: (1) cross the fix, (2) fly outbound roughly parallel to the inbound course on the non-holding side, (3) turn to intercept the inbound track. FEAST spatial visualization includes holding pattern entry selection to test 3D spatial reasoning.
Question 6: Looking at a vertical profile of airspace, an aircraft is at FL230. Below it is Class C airspace from FL100 to FL195, and below that is Class D airspace from the surface to 3,000 ft. Class E airspace fills the gaps. The aircraft at FL230 is currently in:
- Class E airspace — FL195 to the base of Class A airspace (FL550) contains Class E in this scenario (Correct answer)
- Class C airspace — because it is the highest controlled airspace in the scenario
- Class A airspace — which starts at FL180
- Class D airspace — because the aircraft is closest to the high end of Class D
Correct answer: Class E airspace — FL195 to the base of Class A airspace (FL550) contains Class E in this scenario
Class C ends at FL195 and Class A (in ICAO countries) starts at FL550 or higher. The gap FL195–FL550 is Class E airspace. FL230 falls within this Class E block.
In this scenario, the airspace from the surface upward is: SFC–3,000 ft = Class D; 3,000 ft–FL100 = Class E (gap fill); FL100–FL195 = Class C; FL195–FL550 (ICAO Class A start) = Class E. FL230 is between FL195 and FL550, which in this scenario is Class E airspace. FEAST spatial visualisation tasks include reading vertical airspace profiles and determining which class applies at a given altitude — requiring candidates to read and apply multi-layer spatial rules correctly.
FEAST Spatial Orientation and Visualization 2
An aircraft is at FL120, flying heading 180 (south) toward a mountainous area.
The highest terrain ahead is 9,500 ft.
The aircraft has minimum obstacle clearance requirement of 1,000 ft.
The minimum safe altitude for this aircraft on heading 180 in this area is: