Southern California Edison’s (SCE) aerial inspection program uses drones and helicopters to capture high-definition images of distribution and transmission assets, and inspect structures in high-risk fire areas.

While conducting ground inspections in high-risk fire areas in 2019, one thing became clear – SCE needed top-down visual inspections of its assets. Ground inspectors did not have a top-down vantage point that could provide more information about an asset’s condition. Realizing that drones were being used in other parts of the organization, Phil Herrington, SCE’s senior vice president of transmission and distribution, advocated for accelerated adoption of drone technology. While the organization was already using helicopters for aerial image capture, it was not yet prepared to fully deploy drones. A team was created to implement full-scale drone inspections, consisting of stakeholders from public affairs, safety, air operations and environmental services. Under the
direction of Erik Takayesu, vice president of transmission and substation operations, the team moved SCE beyond traditional ground-based inspections. Aerial inspections are not meant
to replace ground inspections of transmission and distribution assets — they complement them.

Gaining a 360-degree view

Equipped with high-resolution, multispectral cameras, aerial and ground inspections provide a 360-degree view of company structures. SCE uses drones in densely populated areas and helicopters in mostly rural areas to take images of assets to help mitigate the danger of wildfires. SCE hired contractors to conduct the inspections. In 2019 and 2020, they inspected about
200,000 transmission and distribution structures a year in high-risk fire areas. SCE can manage risks that may impact the grid by identifying problems before they become potential ignition risks. Some examples include missing cotter keys, leaking transformers, damaged insulators, melted bird guards and other issues. SCE now has an approximate 10% find rate for Priority 2 notifications, which get remediated within six months, and an approximate .25% find rate for Priority 1 notifications, which are considered an immediate ignition risk and get remediated within 24 hours. In 2020, the Priority 1 find rate was about .20% and Priority 2 was about 3%.  The aerial team’s work is divided into collections, inspections and notifications.


Using drones and helicopters, the aerial inspection program deploys various types of sensors to collect different types of information, including high-definition photos, videos, infrared, and LiDAR. They use data to identify issues, analyze risks, and prioritize and remediate the findings. This data is then downloaded onto a secured server. At the program’s peak, 61 drone crews (each crew consists of a pilot and a visual observer) were deployed throughout SCE’s service territory and three helicopter vendors with numerous fleets.

SCE Burned crossarm

Inspections and notifications

Aerial inspections are performed by contracted qualified electrical workers (QEWs) who assess the condition of the captured assets (using SCE standards). An asset can be dispositioned into various categories, depending on its condition. If inspectors identify an immediate ignition risk, they route the information to a QEW, who validates the condition and creates a notification for immediate remediation. Since the inception of the aerial inspection program, the program has been able to mitigate potential hazards by replacing equipment that may have created an ignition risk.


Although there are weekly and monthly image collection goals, many factors can slow down work. High winds, rain and extreme heat can stand down both drones and helicopters. Temporary Flight Restrictions (TFR) set by the Federal Aviation Administration can restrict air travel for various conditions, including hazards that impact flight safety. These TFRs can significantly impact SCE’s ability to meet collection goals because of their unpredictable duration. Access to federal lands, tribal lands, wildlife preserves, and other protected lands also can be a collection challenge for crews. Customer complaints are received due to the noise from low-flying helicopters, so there is some skepticism or mistrust of drones in general. Plus, the COVID-19 pandemic has inflamed those complaints. With more customers under stay-at-home orders, SCE has experienced increased customer complaints about hovering helicopters and drones in backyards. Therefore, the company has posted notifications on social media platforms and conducts door knocks to alert customers of upcoming inspections.

Using AI

SCE uses high-definition images to pilot artificial intelligence models. These machines, built in-house, can learn and identify images through algorithms to help accelerate the identification of immediate fire risk by recognizing possible damaged equipment. When the machine detects an issue, it flags the image for an inspector to validate the damage and dispatch it for immediate remediation. This not only increases inspector throughput and productivity, it also speeds up the inspection process. These models are continuously trained and refined as our algorithms develop intelligence and sophistication, increasing confidence in their capabilities. These machines can recognize deteriorated cross arms, deteriorated poles, and other immediate ignition risk sources. Although the need to have a human validate the damage detected by machines will not completely go away, machine learning and algorithms will refine data quality and enhance and accelerate inspections. This allows the company to operate proactively, rather than remediate reactively. Ongoing future concepts, such as pole identification tag scanning, will expedite decision-making,
eliminate repeat inspections, improve asset data and assist with mapping corrections. Partnering with internal and external stakeholders will continue to be important for the success of aerial inspections at SCE, as it scales programs and capabilities to help further protect customers and communities from wildfires in California.