Backlog is unfilled customer orders for products and product services (expected life of contract sales for product services).

Remaining performance obligation (RPO), a defined term under GAAP, is backlog excluding any purchase order that provides the customer with the ability to cancel or terminate without incurring a substantive penalty, even ifpenalty. In the second quarter of 2021, we expect to replace our quarterly disclosures of backlog with RPO as a key metric, one commonly used across our industries, which will simplify our reporting. Our historical experience indicates the likelihood of cancellation of orders excluded from RPO is remote based on historical experience. We plan to continue reporting backlog as we believe that it is a useful metric for investors, given its relevance to total orders.remote. See Note 9 to the consolidated financial statements for further information.

Adjustments to reported backlog, primarily related to long-term contracts in excess of $160.7one year, of $156.4 billion as of March 31, 20202021 are largely driven by adjustments of $149.9$145.9 billion in our Aviation segment: (1) backlog includes engine contracts for which we have received purchase orders that are cancelable. We have included these in backlog as our historical experience has shown no net cancellations, as any canceled engines are typically moved by the airframer to other program customers;cancelable; (2) our services backlog includes contracts that are cancelable without substantive penalty, primarily time and materials contracts; and (3) backlog includes engines contracted under long-term service agreements, even if the engines have not yet been put into service. These adjustments to reported backlog are expected to be satisfied beyond one year.

Global electricity demand increased during the first quarter of 2020, Power had approximately 700 headcount reductions2021, driving increases in GE gas turbine utilization and notified approximately 1,300 contractors. In addition, we executed on a hiring freeze, are accelerating planned employee reductions where possible, and are initiating meaningful incremental headcount reduction plans in line with the demand profile.

We continue to invest in new product development, such as our HA-Turbines, and upgrades as these are critical to our customers and the long-term strategy of the business.HA-Turbines. Our fundamentals remain strong with approximately $85$78 billion in backlog and a gas turbine installed base greater than 7,000 units.units, including approximately 1,800 units under long-term service agreements.

Profit increased 35% organically* due to incremental power plant scope on unit orders,growth in Gas Power services revenues and margins and continued efforts to streamline the business across Gas Power and Power Portfolio, partially offset by a decrease in Heavy-Duty Gas Turbine unit orders.

RevenuesProfit increased $0.7$0.1 billion (28%(31%) organically*, primarily from 378 more wind turbine shipments on a unit basis, or 112% more megawatts shipped, thanimprovement in Onshore Wind product cost, the prior year,favorable impact of cost reduction measures, primarily at Grid and Hydro, and improved project execution, partially offset by lower Grid revenues, primarily due to COVID-19.

Aviation has and is continuing to taketaken several business actions to respond to the current adverse environment. Weenvironment, including a reduction of approximately 25% of its total global workforce since year-end 2019. The business is actively monitoring the pace of demand recovery to ensure the business is appropriately sized for the future. In addition, we continue to partner with our airline and leasing customers to respond to an increased number of requests for short-term payment deferrals and are working closelyaligned with our airframe customers to alignpartners on production rates for 2020. During the first quarter of 2020, Aviation took several measures including a hiring freeze, cancellation of salaried merit increases,2021 and a reduction of all non-safety related discretionary spending, including capital expenditures and engineering and development efforts. Aviation also announced a reduction of approximately 10% of its total United States (U.S.) workforce and a temporary furlough impacting approximately 50% of its U.S. maintenance, repair and overhaul employees for 90 days. Additionally, Aviation announced a temporary furlough impacting its U.S. assembly operations and component manufacturing shops for approximately four weeks during the second quarter of 2020. Aviation is also working with the appropriate parties to properly address its global workforce.beyond.

As it relates to the military environment, Aviation continues to forecast strong military demand creating future growth opportunities for our Military business as the U.S. Department of Defense and foreign governments have continued flight operations, and have increasedallocated budgets to upgrade and modernize their existing fleets, creating future growth opportunities for our Military business.fleets. During the first quarter of 2021, Aviation continued to experience supply chain challenges, which the business is actively addressing.

Total engineering, comprised of both company, customer and customer funded spending,partner-funded and nonrecurring engineering costs, decreased compared to prior year. Company-fundedyear in line with the changes in the commercial environment. During the first quarter of 2021, company-funded research and development spend decreased compared to the first quarter of 2019,prior year. Customer and we expect the reduction to continue in line with the actions outlined above. However, customer-fundedpartner-funded engineering efforts, primarily in our Military business, continueddecreased compared to increase.

Profit decreased $0.4 billion (37%) organically*, primarily due to lower volume on commercial spare part and commercial spare engine shipments, and decreased shop visits in our service agreements, due to the impact of COVID-19. Military revenues decreased due to lower volume of engine and spare part shipments,agreements. These decreases in profit were partially offset by increased revenues on development contracts.

credit risk givenand declines in the estimated profitability in long-term service agreements not repeating in the current environment. In addition, Aviation recorded a $0.1 billion non-cashyear.

We continue focusing on creating new products and digital solutions as well as expanding uses of existing offerings that are tailored to the different needs of our global customers. In the first quarter of 2020, weGE Healthcare introduced the LOGIQ™ E10 Serieslatest member of the Venue™ point of care ultrasound family. We also introduced Vscan Air, a cutting edge wireless pocket-sized ultrasound that is powered by advanced algorithmsprovides crystal clear image quality, whole-body scanning capabilities, and intuitive software. We received 510(k) clearance for OEC 3D surgical c-arm. OEC 3D sets the same artificial intelligence technology behind advanced gaming. It can process 10 timesstandard of interoperative imaging with precise 3D volumetric images for spine and orthopedic procedures combined with 2D imaging for greater everyday efficiency. We remain committed to innovate and invest to create more dataintegrated, efficient, and generate images faster than our previous ultrasound systems to help clinicians bring fast, precise answers to their patients. We continue to ramp production of critical medical equipment used to diagnose and treat COVID-19 patients, respiratory, computed tomography (CT), monitoring solutions, x-ray, anesthesia and point-of-care ultrasound product lines.personalized precision healthcare.