April, 2017
Inspection News and Views from the American Society of Home Inspectors

Using Drones: The Eye in the Sky


Filling a Need

Inspecting a roof can be a tricky and dangerous business. Safety is always a primary concern for the inspector and others in the vicinity. “Accidents waiting to happen” revolve around the use of ladders, steep roof slopes and unsure footing.

In addition, inspectors should not traverse roofs that are in poor condition or that have a roof covering that can easily be damaged.

Finally, some roofs are out of a ladder’s reach and are just not accessible. My biggest nightmare is a low-slope roof that cannot be viewed from the ground and is out of the reach of my ladder. Now what? For me, reporting that the roof was inaccessible and could not be inspected is not an option.

Enter the Drone
Every so often, a product that makes inspections easier and better hits the market. One example is the thermal imaging camera, which is increasing in popularity and becoming more affordable.

Another product gaining popularity in the recreational and photography markets is the unmanned aerial vehicle (UAV) or drone.

By definition, a drone is an unmanned, rotary-wing aircraft. Aircraft are of two types: fixed and rotary wing. Fixed-wing aircraft include gliders, commercial airliners and the like. They get their lift from air moving over the wings. These aircraft must maintain a minimum, forward speed to fly. This type of drone will not work for roof inspections.

The second type—rotary-wing aircraft—includes helicopters and drones that get their lift from one or more horizontally rotating propellers or rotors. Because it is the rotor, not the aircraft, that moves through the air to get lift, these aircraft can hover and their ability to hover makes the rotary-wing aircraft an ideal option for inspecting roofs.

Drones have an even number of rotors. Half of the rotors rotate clockwise and the remaining rotors rotate counterclockwise to cancel the motor torque, thereby keeping the drone from spinning. Drones are usually quadcopters (four blades) or hexacopters (six blades).

The Good News and the Bad News
Drones have properties that lend themselves well to the inspection industry. A drone never makes contact with the roof, so there is no chance that it will damage the roof covering. The drone “traverses” the roof, leaving the inspector safely on the ground. Roofs are no longer limited to ladder accessibility (Photos 1 and 2). Also, a drone is easier and more compact to transport than a ladder that is 22 feet or longer.

Nothing is perfect. Drones do have drawbacks. They should never be flown in rain, snow, high or gusty winds, or when the temperature is extreme. Drones can’t check shingle-to-shingle bonding, the presence of drip-edge flashing or the resilience of the roof decking. (Checking bonding and flashing can be done from a ladder on a lower section of the roof; checking decking resilience can be done in the attic.) It’s important for the inspector to always keep the drone (aircraft) in sight during flight.

Legal Eagles and Liability
Because of drone collisions, airspace incursions and near misses with aircraft, the Federal Aviation Administration (FAA) has clamped down on people who use drones. The FAA’s Small Unmanned Aircraft Regulations (Part 107; refer to www.faa.gov/news/fact_sheets/news_story.cfm?newsId=20516 ), which became effective in August 2016, require commercial drone users (that’s us) to be certified every two years, as well as to adhere to the current drone registration requirement. FAA regulations prohibit drone flight in Traffic Control Areas (TCAs) near airports, as well as flying more than 400 feet above ground level (AGL), over crowds, near emergency workers and in restricted airspace. There are also other restrictions that come under the heading of “common sense.”

As a drone operator, you are responsible and legally liable for any damage and personal injury caused by your drone. However, considering the liability related to ladder use and traversing roofs, in my opinion, it’s a wash.

A few months ago, I contacted my insurance carrier to determine the rulings and policies on drone use for inspections. Because drones are a relatively new part of the big picture of home inspection, my insurance carrier had no official policy in place. This will likely change with the increased use of drones by home inspectors.

Selecting a Drone
Okay, so you’re considering buying a drone. Where do you start?

A good way to start is by visiting drone clubs’ websites, drone use forums, independent drone reviews and manufacturers’ websites that provide technical information and product features. Learn as much as you can about drones and their capabilities, characteristics and limitations.

Decide which features and attributes are important to you. For me, ease of flight control, stability, flight battery capacity and an on-board camera are musts. Keep in mind that your primary focus will be flying the drone; taking pictures will only occur during momentary interludes. I chose DJI’s Phantom 3 Standard (www.dji.com/phantom-3-standard) because of its onboard flight stabilization features: compass, barometer, gyroscopic stabilization and, best of all, GPS locking.

Keep in mind that, without on-board, intelligent control, you cannot fly a drone. A drone is inherently unstable. Most drones may have additional features that may not be important to you. Select the product that best fits your needs. Although I am not specifically promoting DJI’s Phantom 3 Standard, it is the one I use and know.

The Phantom’s camera takes crisp, 4.5 MB photos, and it can switch between video and still modes at a finger’s touch. I do not take videos; I find that the video frame resolution does not obtain a crisp image, even when the photo is reduced to a size suitable for a report. Instead, I operate in still mode and crop the photos to highlight selected features. Image size should be 4 MB or larger.

What is the flight time with a full battery charge? You will probably need 15 minutes or more of flight time to cover an average-sized roof. The Phantom 3 has a flight time of 25 minutes at an air temperature of 70 degrees. Keep in mind that a battery’s capacity will decrease with decreased air temperature. In cold weather, for example, you may not get more than 15 minutes on a full charge.

Before you buy, check out the manufacturer and ask yourself these questions: Does the manufacturer offer good product and technical support? Is the company responsive to questions? Does the website provide online tutorials? What is the warranty policy?

Once you’ve selected your drone, you can build your kit. Of course, you will need the drone and a controller. The Phantom 3 comes with a separate remote control—nice. Invest in a spare battery. You may need it if you will be conducting multiple-unit inspections or if you are inspecting a large, complex roof. I highly recommend obtaining propeller (rotor) guards. The last thing you need is to break a rotor and crash onto an inaccessible roof. I also recommend investing in a quality carrying case. I have a case (by GoPro) that is specifically designed to hold the DJI Phantom 3 series. It cost $350, but I believe that it is well worth the cost to protect my investment.

By the time you purchase all the items you need, your drone kit likely will cost you at least $1,000. But again, in my opinion, considering the freedom, versatility and safety the drone affords me, the investment has been well worth it.

Before You Inspect
The natural impulse might be to grab your brand new, untested drone kit and whisk off to your first inspection. Don’t do it! Flying requires specific skills and hand-eye coordination that can only come with knowledge and practice.

Read the manual first. Most likely, it will be a downloadable document. I printed out the manual for my drone and then I read it five times before flying. Get to know the features and operating procedures for your drone. Watch online tutorials.

Assemble your drone in accordance with the manufacturer’s instructions. You most likely will have to attach the propellers (rotors) and the propeller guards (recommended). Make sure the batteries are fully charged before flight. The Phantom 3 drone system consists of three parts: the remote controller, which contains the flight controls; the aircraft itself, which is a quadcopter; and an iPhone or Android mobile device (not included), which serves as both the “cockpit window” via video feed and the instrument panel. The drone application can be downloaded from the manufacturer.

Before your first flight, make sure your mobile device is connected (typically via Wi-Fi) to your controller and that there is a definite link with the aircraft (drone). Wait until you have GPS acquisition before flying, especially the first time. Start the rotors and slowly ascend to about 5 feet AGL. Get the feel of the flight controls by maneuvering your aircraft in a safe area. Check the camera gimbal operation and take some shots of ground features. As you become more familiar with your aircraft’s flight characteristics, go higher and farther.

Practice a roof inspection on your own home. Practice hovering in a stable manner over a fixed point below; this is the most frequent and the trickiest flight maneuver you will need to perform. The Phantom 3 aircraft camera connects to a computer via the included cable, which plugs into a standard USB port for image download. The camera looks like any other external storage device for the computer.

I highly recommend that you spend at least 10 hours in practice flight mode before you take your drone on an inspection. You should be as comfortable flying the drone as you are driving your car. Aircraft operation must be instinctive; you won’t have time to think and wonder during a drone flight that’s part of an inspection.

All drones must be registered with the FAA (to register, visit www.faa.gov/uas/). I recommend that you wait to register until you are sure that your drone operates properly and that you have selected the drone that is right for you. This should not take more than a couple hours of flight time.

Flying High
We are used to getting in our cars and driving off. If your car quits, all you need to do is pull over to the shoulder and summon assistance or make the necessary repairs. Operating an aircraft is quite different. Eventually, every aircraft will land. The question is, how will it land?

Specific checks must be made before flight to ensure that your aircraft is in good condition and calibrated. This procedure is called preflight. Part of the normal preflight procedure should be checking the rotors and guards for damage. Do not fly with a damaged rotor! Check the aircraft itself for damage and ensure that the camera is mounted properly. Check the flight battery level. It should be fully charged before flight. DJI also recommends compass calibration when flying in a new location. Make sure there are no metal objects nearby, as they will throw off the compass. I always take off my watch and remove keys from my pocket before compass calibration.

Take off slowly and note the sound the aircraft makes. If it sounds irregular or unusual, or if it exhibits any unexpected instability, land immediately! Observe FAA regulations; do not fly in rain, snow or high winds and gusts.

During flight, always keep the aircraft in sight. Most of your attention should be on the aircraft’s behavior and position, with occasional glances to your “instrument panel” (mobile device). If the aircraft ducks behind an obstruction, it could lose communication with the remote controller. The Phantom 3 has a return-to-home (RTH) feature that automatically brings the aircraft back to its takeoff location if the controller signal is lost. If you have to move from the front to the back of the house, increase the aircraft’s altitude so it is always hovering in sight as you move to the back, then bring it back down to continue your inspection.

Be aware that, during inspections, you will be using the drone in a manner that most manufacturers recommend you don’t  do: flying close to obstructions. Keep at least a 2-foot distance from obstructions in case the aircraft drifts or is pushed by a wind gust.

All aircraft use fuel. Larger aircraft use either gasoline or jet fuel. Drones use electricity. Think of the aircraft battery as a fuel tank and land when it gets low (below approximately 25 percent). Don’t push it! If you run out of “fuel,” the aircraft will  land in an undesirable and possibly destructive manner.

The advent of drones has opened up new horizons to home inspectors, just as thermal imaging cameras did in the recent past. So, should you invest in a drone? Only you can answer this question. Just as your job is to enable a homebuyer to make an informed purchasing decision, you should apply the same philosophy when you make a decision about whether to incorporate a drone into your inspection business. For me, it was the right move. I’ve been able to perform more thorough inspections without risking my neck or damaging a roof. My drone has certainly paid for itself.

Ron Greene is Owner-Operator of Golden Eagle Home Services LLC, Mountlake Terrace, WA. He is certified by ASHI and InterNACHI. He has been a licensed home inspector for about three years, after having been a handyman for eight years.