What happens if an air taxi loses power?
The pilot has to be able to land it under control. That’s the line the FAA and EASA draw for a certified air taxi. After a critical failure, the aircraft has to stay controllable. After a total loss of power, it still has to come down where the pilot steers it, by gliding, autorotating, or an equivalent method. This guide covers what the rules require, what the companies say they built, and what NASA has studied. It isn’t an incident record. We read every source on October 28, 2026.
Last updated October 28, 2026.
What do the FAA and EASA require?
The FAA writes a separate set of airworthiness criteria for each powered-lift aircraft. Its final criteria for Joby’s Model JAS4-1 took effect April 8, 2024, and its criteria for Archer’s Model M001 took effect June 24, 2024. Both say that “continued safe flight and landing must be possible from any point within the approved flight envelope following a critical change of thrust.” A critical change of thrust is “the most adverse effect on performance or handling qualities resulting from failures of the flight control or propulsive system, either singular or in combination, not shown to be extremely improbable.” Sources: Federal Register, Joby criteria, March 8, 2024 (opens in new tab) · Federal Register, Archer criteria, May 24, 2024 (opens in new tab). How the FAA certifies powered-lift air taxis explains why each aircraft gets its own criteria.
The criteria set two levels. “Essential performance” means the aircraft can keep flying under control and land, possibly using emergency procedures. “Increased performance” means it can climb to a safe altitude and hold level flight to the planned destination or an alternate landing site. The FAA calls increased performance “a higher level of safety that guarantees fly-away capability after any failure not shown to be extremely improbable.” An aircraft may be approved for either level, or for both with different operating limits. Source: Federal Register, Archer criteria, May 24, 2024 (opens in new tab).
EASA uses two categories instead. Under its special condition, Category Enhanced means “continued safe flight and landing,” which includes landing at a vertiport. Category Basic means a “controlled emergency landing.” An aircraft meant for flights over congested areas, or for carrying passengers commercially, must be certified in Enhanced. The current text is SC-VTOL-02, Issue 2, dated June 10, 2024. It raised the maximum takeoff mass to 5,700 kilograms and kept the two categories from Issue 1, dated July 2, 2019. Sources: EASA, SC-VTOL-02 Issue 2, June 10, 2024 (opens in new tab) · EASA, SC-VTOL-01 Issue 1, July 2, 2019 (opens in new tab). Some commenters asked the FAA to adopt EASA’s approach. The FAA said it “disagrees and has instead adopted” its own two levels. It calls them “similar” to EASA’s Basic and Enhanced, but adds that “differences remain.” Both regulators’ levels include a controlled emergency landing after a total loss of power or thrust. Source: Federal Register, Joby criteria, March 8, 2024 (opens in new tab). Are air taxis safe? covers how the two regulators set safety targets.
What if all the power is gone?
The aircraft still has to land under control. Both FAA criteria say it “must be capable of a controlled emergency landing” after it can no longer provide the power or thrust needed to keep flying, “by gliding or autorotation, or an equivalent means.” The FAA defines a controlled emergency landing as one where the design lets the pilot “choose the direction and area of touchdown while reasonably protecting occupants from serious injury.” Some damage to the aircraft may be acceptable. Sources: Federal Register, Joby criteria, March 8, 2024 (opens in new tab) · Federal Register, Archer criteria, May 24, 2024 (opens in new tab).
The FAA says the aim is to match what older aircraft already do. Its notes say the definition is meant to give “equivalency to the part 23 airplane gliding requirements and the part 27 rotorcraft autorotation requirements.” The rule is meant to hold “in the event of cockpit mismanagement, energy exhaustion, improper maintenance, or other failures,” so running a battery too low counts. The FAA left the method to each company, and a conventional forward landing may be acceptable if the aircraft can make a controlled emergency landing that way. Source: Federal Register, Joby criteria, March 8, 2024 (opens in new tab). For how reserve energy is set, see how far an air taxi can fly.
We searched the FAA’s two sets of criteria and EASA’s SC-VTOL-02 for the word “parachute” on October 28, 2026 and found no match. Don’t assume a whole-aircraft parachute is part of the requirement.
How do designs spread the risk?
By splitting power into parts that fail one at a time. EASA’s special condition says energy storage and supply systems must be independent, “so that a failure, including fire, of any one component in one system will not result in the loss of energy storage or supply of another system.” It also says storage must provide “a sufficient reserve based on a standard flight.” Source: EASA, SC-VTOL-02 Issue 2, requirement VTOL.2430, June 10, 2024 (opens in new tab). In the Archer criteria the FAA says “propulsion system failures include the electrical distribution and batteries.” Source: Federal Register, Archer criteria, May 24, 2024 (opens in new tab). How air taxis charge covers the batteries themselves.
Here’s what two companies say about their own aircraft. These are design claims, not test results we ran.
- Joby says its aircraft has six electric motors, four battery packs, a triple-redundant flight computer, and dual critical actuation systems. It says the battery has “four independent packs with fault isolation,” and that “system-wide redundancy keeps the aircraft safely airborne even in the rare event of a component failure.” Joby also says the aircraft is “in the final stage” of FAA design certification. Source: Joby, technology page (data as of December 2025), read October 28, 2026 (opens in new tab).
- EHang says key flight-control and power systems on the EH216-S “have multiple backups.” It says a fail-safe system monitors the aircraft’s health and decides “whether to continue flying or execute a safe emergency landing.” China’s CAAC certified this pilotless aircraft, not the FAA or EASA. Source: EHang, EH216-S page, read October 28, 2026 (opens in new tab). Our EH216-S guide has the certificate history.
Neither page says what the aircraft does after a given failure, and neither is a certification finding. For Archer we cite only the FAA’s text. Compare the two U.S. designs in Joby vs. Archer.
How does that compare with a helicopter?
A helicopter relies on autorotation. The FAA’s handbook calls it “a power-off maneuver in which the engine is disengaged from the main rotor disk and the rotor blades are driven solely by the upward flow of air through the rotor.” It says the most common reason for one is engine or drive-line failure. Source: FAA, Helicopter Flying Handbook, chapter 11 (FAA-H-8083-21B, 2019) (opens in new tab). The FAA’s powered-lift rule builds on that idea. A powered-lift aircraft that has shown it can autorotate, or do an approved equivalent maneuver, may follow the minimum safe altitudes that apply to helicopters. Source: FAA, powered-lift rule FAQ, updated October 22, 2024 (opens in new tab). The rule text sets a floor. For Part 135 operations, the FAA may authorize a lower minimum altitude if type certification shows the aircraft can autorotate or do an approved equivalent maneuver, but no lower than 300 feet above the surface. Source: 14 CFR 194.306(mm), read October 28, 2026 (opens in new tab). Air tours get a height-and-speed rule. For a powered-lift with height-velocity data in its flight manual, the pilot may fly only at a height and speed that would allow a safe landing after engine power loss or a critical change of thrust. Takeoff, landing, and hover transitions are exempt. Source: 14 CFR 194.308, read October 28, 2026 (opens in new tab). For the broader comparison, see air taxi vs. helicopter.
How are pilots trained for it?
The rule lists the drills. A powered-lift training program under Appendix A to Part 194 must cover “emergency procedures and equipment malfunctions” and “approaches to a landing with simulated engine malfunctions.” For a multiengine powered-lift it adds “simulated one-engine-inoperative approaches and landings.” Source: 14 CFR Part 194, Appendix A, section 10, read October 28, 2026 (opens in new tab). Those rules apply to aircraft with a pilot on board. The FAA says its powered-lift rule doesn’t cover unmanned aircraft. Source: FAA, powered-lift rule FAQ, updated October 22, 2024 (opens in new tab). Pilotless designs fall outside that rule. See manned or autonomous? and are air taxis drones?
What has NASA studied?
NASA has looked at how these aircraft handle failures in concept designs, not in any company’s aircraft. A June 2019 report by Boeing for NASA studied four concept vehicles’ propulsion systems. It defined an “avoid region” of low-speed, low-altitude flight. There, one failed propulsion unit means “power required exceeding power available and a hard landing sufficient to cause Critical or Severe damage to the aircraft or occupants.” The study assumed the vehicles spent 20 percent of flight time in that region. Source: NASA/CR-2019-220217, June 2019 (opens in new tab).
A May 2023 NASA paper tested a lift-plus-cruise concept with propulsion failures in hover and low-speed flight in a piloted simulator at NASA Ames. Its authors found that modeling control saturation was “a significant finding.” They also wrote that “no attempt was made to identify the critical propulsion failure scenario, and this remains a topic for future research.” Source: NASA, Altamirano et al., presented May 2023 (opens in new tab). Both studies are simulations or analyses. Neither tells you how a specific air taxi will behave.
What does this mean for a ride?
Know what the approval says. Which level an aircraft holds will matter for flights over a city, and only certification can settle it. Weather and landing sites matter too. See how air taxis handle rain, wind, and snow and what a vertiport is. U.S. passenger service depends on certification, so watch when air taxis launch. For the eVTOL basics, read what eVTOL means. The air taxi glossary defines the terms. For how controllers handle an aircraft in trouble, see air traffic control and air taxis. For Archer’s status, see its company page.