# Multirotor Flight Training In Close Proximity of Structures, Vegetation, and Power Lines

• Pilot and observer procedures

• Anticipated aircraft behavior, updrafts, wind shear mechanical turbulence



## • Anticipated autopilot behavior, GPS poor flight, Attitude, manual

1 © Alfred A. Gates, 2014

# Pilot and Observer Procedures

• The observer has equal rolls in producing a safe and beneficial flight around structures

• When the plot maneuvers a multicopter to a safe distance away from the target he will stop and hold position. The observer will then guide the pilot to a closer position by observing the aircraft from different positions and by using the video feed to guide the pilot.

• The pilot should not move from his view point once the observer is providing guidance. Also the pilot should only be looking at the aircraft and if he must look at the controller he should move the controller to his line of sight.

• In close proximity of structures, vegetation and lines, the observer will have a better understanding of the position of the aircraft.

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# Pilot and Observer Procedures

• During any stage of the 

## flight

• The pilot will put the transmitter in the field of 

## view to check the flight status, GPS signal strength, battery strength.

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# Pilot and Observer Signals

• Pilot performs all preflight

• Pilot takes off, hovers and 

## performs inflight checks.

• Pilot maneuvers aircraft to a safe distance from structure 

## and holds position in GPS hold mode ( provided the satellite signal strength is strong enough)

45  Pilot maneuvers multirotor to safe distance from structure

 Observer starts to advise and guide the pilot to the inspection position

 Pilot holds position at inspection point  Observer operates camera, zoom, pan tilt, photo and video6  Pilot: Eyes always on the multirotor  Observer: Advises pilot during every position change

• Operates all camera functions

• Moves around to vide aircraft from different angles

• Uses video feed to advise pilot7  Once all inspection is complete.  Observer guids pilot away from structure to a safe position where the pilot can fly the aircraft unassisted

Pilot can now safely land the aircraft

# Winds/ Weather

• On calm days the winds were stronger than anticipated requiring the pilot to manually fly the multirotor in close proximity to the structures and power lines.

• Biggest limiting factor is weather. Winds greater than 5KTS coupled with other factors that create wind require over riding the GPS mode.

• Can not fly in rain or snow showers.

• A highly experienced pilot is required.

• The observer has a higher work load than anticipated.

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 8

# Navigation

• It is safer to navigate around wires in GPS position hold mode provided the autopilot is capable of maintaining position in the winds. This allows the pilot time to slowly maneuver the aircraft into position. The observer is advising the pilot in close proximity of lines and structures.

• The pilot needs to be ready to switch modes if the aircraft is blown out of position or if the GPS signal becomes weak.

• The maximum pitch and roll angles are decreased in GPS mode when compared with the stabilize and altitude flight modes.

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 9Or no wind

This will occur around tree canopies Shear Zone : This will cause a multicopter to move in pitch and roll to maintain attitude control. Wind T op Zone: the aircraft can be blown out of view. FAA Pilots Handbook

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 10Still air

Wind Multirotor can be blown out of view

Wind shear event

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 11Anticipating

• Flight in turbulence (aircraft will move around more)

• Aircraft will be blown in one direction. Pilot is ready to switch modes Wind shear Video: Wind at top of structure

Aircraft was being blown out of view Above tree canopy. Pilot had seconds to switch modes

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 12Terrain turbulence

Mechanical Turbulence

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

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Operations Program 13 Convective Currents

## Multirotor UAS Flight Modes Commonly Uses For Structural Inspection

• Stabilize, Manual: Keeps the aircraft level if the control sticks are released. Does not hold position or altitude (Pilot has the most control authority)

• Altitude: keeps the aircraft level and at the current altitude if the sticks are released. Does not hold position (Change and altitude is limited by the maximum/ minimum throttle setting programmed)

• GPS Hold/ Loiter: Holds position and yaw if the stick are released. Depends on a good GPS signal. (Change in altitude and attitude is limited by the maximum control settings for pitch, roll, yaw and altitude) Pilot has the least control authority

2015 AHS Specialist’ Meeting on Unmanned Rotorcraft and Network

- Centric

Operations Program 14

## Anticipated autopilot behavior, GPS poor

flight, a ttitude , manual

• The pilot must anticipate that the GPS signal 

## strength will decrease. (Be ready to switch modes)

• The pilot must anticipate wind shear, updrafts, 

## wind gust and wind changes. (Be ready to switch modes)

• The pilot must anticipate what the multirotor will do in the event of wind shear, updrafts, wind gust and wind changes

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# Updrafts

• Updraft: Multirotor will climb in position. 

## Throttle min position will not be low enough to maintain altitude.

• Pilot response:



## • If structure is above switch to manual mode. Manual mode provides more altitude control authority

• If there is no structure above. Let the aircraft climb and wait and see it the updraft decays

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# Wind Shear

• Wind Shear : Multirotor will pitch and roll and possibly move away from the hover position.

• Pilot response :

• If structure is close switch to Altitude mode. Altitude mode has the same pitch, roll and YAW min, max settings as the manual mode.

• If there is no structure close by. Let the aircraft move around and fly the aircraft through the wind shear zone.

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# Wind Gust, Wind Increase

• Wind Shear: Multirotor will blown in one direction.

• Pilot response:



## • If structure is close or if the multirotor is being blown out of view switch to Altitude mode. Altitude mode has the same pitch, roll and YAW min, max settings as the manual mode.

• If there is no structure close by. Let the aircraft move around and see if the wind gust will died down

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# GPS Signal Strength Reduction or

Signal Loss

• When the GPS signal becomes weak. The 

## aircraft will chase a unknown GPS position at the maximum pitch and roll positions. The aircraft will maintain altitude.



## • The pilot must immediately switch modes to a none GPS mode, Altitude or Manual.

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