ATLC

Question 1

What does ATLC stand for?

Answer 1

Automatic Takeoff and Landing Capability

Question 2

When might the laser altimeter experience inaccuracies?

Answer 2

Precipitation, airborne dust, or other particles (fog)

Select radar altimeter as the AGL sensor in HDD (override)

Question 3

What are the 10 points of the ATLC mission?

Answer 3

1 = pattern entry (start of downwind)
2 = turn to base (start of base)
3 = initial approach fix (start of turn to final)
4 = final approach fix (default entry waypoint & glide slope intercept and descent from pattern altitude)
5 = runway start point (start of runway)
6 = flare point (flare begins at 30 ft AGL)
7 = touchdown (target touchdown point at least 1,500’ from start of flare)
8 = slope survey (determines runway slope)
9 = rollout (ground tracking reference for takeoff and landing roll)
10 = departure (target waypoint after takeoff or landing abort and set 12,000’ past WP 9 at glideslope intercept altitude)

Question 4

What is the default entry waypoint of an ATLC mission?

Answer 4

WP 4 (WPs 1-4 may be selected)

Question 5

What is the purpose of the minimum altitude MSL?

Answer 5

Sets a “hard deck” to protect aircraft during approach descent

Aircraft will not descent below that altitude until passing ATLC entry waypoint then it will descent in accordance with ATLC mission

Question 6

What is the ATLC speed command?

Answer 6

Vs x 1.23

Question 7

What is pitch/roll clamp?

Answer 7

Less than 30’ AGL pitch/roll ranges are reduced until touchdown to limit large changes close to the ground

Example:
30’ AGL pitch limited to -15-+20 degrees and roll 20 degrees of bank
5’ AGL pitch limited to -1-+7 degrees and roll 9 degrees of bank
2’ AGL pitch limited to +1-5 degrees and roll 8 degrees of bank

Question 8

What is the ATLC default profile?

Answer 8

Glideslope = 3 degrees
Glideslope intercept altitude = 700ft AGL
Final Turn Range = 3.2 NM

Question 9

What is the ATLC stopping procedure?

Answer 9

Triggered when aircraft is below 1 foot AGL and one wheel registers 20kts or greater

> 85 KIAS = ground idle
85 KIAS = reverse thrust
20 KGS = ground idle and brakes 100%

Question 10

What are the ATLC arming criteria?

Answer 10

Airspeed = <50 KIAS
Groundspeed = <2 kts
Heading Error = <5 degrees
Cross Track Error = <15 ft
Laser sensor quality = valid
Baro-GPS altitude error = <100 ft
Speed Lever = >99.4%
Closed Loop Power = ON
Throttle = <10%

Question 11

What will happen if ATLC is left on in the pattern?

Answer 11

Aircraft will continue flying the pattern at pattern altitude until ATLC is turned off or an ATLC landing is enabled

Question 12

How can a pilot initiate an ATLC landing abort?

Answer 12

Pull back on control stick at least 5 degrees

Question 13

How can a pilot initiate an ATLC takeoff abort?

Answer 13

Press on both brake pedals >10%
(Continual application of brakes not required)

Question 14

What will happen if a landing abort is detected prior to WP 4? After WP 4?

Answer 14

Before WP 4 = fly pattern waypoints till WP 4 then straight to WP 10
After WP 4 = climb at best climb airspeed to 100ft of pattern altitude then level off at pattern airspeed and altitude and continue to fly the pattern waypoints

Question 15

Can the aircraft automatically abort a landing after a touchdown has been detected?

Answer 15

Normally no but two exceptions

1. Bounce abort if aircraft rises 1.5ft above GDA (ground detection altitude)
2. Minimum stopping distance abort (distance to rollout point compared to stopping distance calculations)

Question 16

What is the takeoff commit point?

Answer 16

The point at which the aircraft no longer has sufficent runway to come to a complete stop
(Meaning stopping distance is greater than runway remaining)
Abort ignored

Question 17

When is the aircraft committed to takeoff?

Answer 17

When it reaches the commit point or reaches rotation speed before the commit point (logic transitions to rotation)

Question 18

Explain ATLC Lost Link Logic

Answer 18

Uplink/downlink failure aircraft waits 2 seconds to see if link returns, if link does not return after two seconds begins ATLC Lost link Logic:

ATLC Landing
If before WP 4 it will fly through waypoints to waypoint 4…
At/after WP 4 it will climb to pattern altitude and WP 10 (departure waypoint)
After arriving at departure waypoint it will transition to standard lost link procedure (mission)

ATLC Takeoff
On ground before commit point = stop and kill engine
On the ground past commit point or in the air = WP 10 then lost link procedure

If link returns while in the air with either ATLC landing or takeoff aircraft will return to ATLC mission at pattern entry waypoint

Question 19

What is ATLC ground lost link logic?

Answer 19

Goal: stop aircraft quickly and shut down to be recovered

1. Brakes are engaged
2. Engine kill delay timer 60 seconds then shuts down engine, strobes, KuADT, INADT
3. Brake release delay timer 600 seconds (10 min) then then brakes release

Note: when entering lost link logic if aircraft is unable to stop within 5 seconds or ground speed >25 kts engine, strobe lights, KuADT, and INADT immediately shut down and brake release timer started

Question 20

When does a linear brake calibration normally occur?

Answer 20

Automatically while on the ground after power up and while in the air when gear is down and aircraft past WP 2, 3, or 4.

If they fail must perform a manual calibration through HDD M keys
Will not cause an ATLC abort but differential braking will not be available

Question 21

Can enhanced taxi over Inmarsat be performed?

Answer 21

No it is prohibited because the Inmarsat link can be unreliable and experience long delays

Question 22

What are the entry conditions for taxi heading hold mode?

Answer 22

UAV on ground
Throttle at ground idle +/-2%
Engine speed command at 87% +/-2%
UAV in DEEC
UAV GS <2 kts

Question 23

What are the entry conditions for taxi centerline hold mode?

Answer 23

UAV on ground
Throttle at ground idle +/-2%
Engine speed command at 87% +/-2%
UAV in DEEC
UAV GS <2 kts
Runway file selected and loaded in GCS
UAV within 18’ of runway centerline
UAV heading within 11 degrees of runway survey point and runway heading

Question 24

How can Pilot quickly switch between taxi heading hold and taxi centerline hold?

Answer 24

Press button 2 on throttle
(Must be <10 kts GS to switch from centerline hold to heading hold)

Question 25

Can the aircraft switch from taxi centerline or taxi heading hold directly to ATLC takeoff mode?

Answer 25

Yes, but not normally done

Question 26

Can taxi centerline hold be used to back taxi a runway?

Answer 26

Yes, the software is bi-directional and will automatically determine intended runway taxi direction based on current aircraft heading and closest runway heading

Question 27

What will the aircraft do when it approaches the end of the runway in taxi centerline hold mode?

Answer 27

If the aircraft taxis within 200’ +/-10’ it will automatically stop