How Solar Storms and Cosmic Radiation Impact Aircraft Maintenance Operations

An airliner cruises at FL370 when a flight computer reboots and a cockpit display flickers, with no fault in sight. The cause traces back to the sun. Solar storms and cosmic radiation impact aircraft maintenance operations well after touchdown, since diagnostics, sensor recalibration and certified repair station clearance can all precede the aircraft's return to service.

Space Weather Impacts Airplanes at Cruising Altitude

Air in the atmosphere absorbs a portion of incoming cosmic and solar radiation, so each layer an aircraft flies through reduces that protection. At FL320 to FL400, most of the atmosphere lies below the airframe, which is why space weather impacts airplanes more directly than it affects anything on the ramp.

The Federal Aviation Administration (FAA) Advisory Circular 120-61B also ties dose rate to latitude, solar activity and time aloft, and it puts polar galactic cosmic radiation at about double the geomagnetic equator level at a given altitude. On a high-latitude route, a descent after a solar radiation alert can considerably reduce radiation exposure if the crew responds quickly.

A flare also ionizes the lower ionosphere in the sunlit hemisphere, and the added absorption can degrade or block high-frequency radio used by commercial carriers. Geomagnetic storms pose a navigation problem, because GPS receivers cannot model the surge in ionospheric electrons and position errors enter the solution.  

During the May 2024 Gannon Storm, the FAA's Wide Area Augmentation System lost its vertical guidance capability at roughly 2,000 airports across the continental United States and Alaska for two days. The FAA's Office of Commercial Space Transportation says this forced pilots to rely on less precise backup approaches to reach the runway.

Avionics Single-Event Upsets After Solar Radiation Exposure

A high-energy particle that reaches a flight computer or sensor package can disturb the stored state of a single microelectronic cell. The component then works from a corrupted value. Thus, avionics single-event upsets of this kind leave the silicon undamaged, yet the symptoms range from a spontaneous reboot to erratic output.

The FAA's space weather program lists onboard electronics reboots and anomalies among the consequences of adverse space weather, next to communication loss and degraded navigation. It also calls for better hazard data at FL320 to FL400, the band where most airliners spend their cruise.

2022 research on field-programmable gate arrays with static random-access memory shows that configuration memory upsets persist until the bit is rewritten via scrubbing or full reconfiguration. A unit that boots cleanly may still run with an uncorrected fault. Maintenance teams must therefore verify the system rather than trust the reboot.

In late 2025, Airbus traced an uncommanded pitch event on a commercial A320 flight to a flight control computer vulnerable to intense solar radiation. This finding prompted an emergency airworthiness directive requiring roughly 6,000 Airbus A320-family aircraft worldwide to either update their flight control software or replace the affected hardware before resuming operations.

Sensor Recalibration Follows an Upset Event

After an upset event, the output of an affected sensor cannot be guaranteed until it is tested. Operators may compare each live reading against a trusted reference value and adjust any unit that falls outside tolerance before declaring the system dependable. This comparison relies on active measurement, since a drifting sensor can keep reporting believable numbers.

Section 91.411 of the federal aviation regulations requires an airplane flying under instrument flight rules in controlled airspace to have its altimeter and static pressure systems tested every 24 calendar months, with another test after any opening of the static system. The rule covers hardware, but it shows how the industry relies on checking instruments against a standard.

Certified Repair Stations Clear Flight Computers After Upsets

Once an upset event casts doubt on a flight computer, airlines may route the recalibration work to a certified repair station. Federal Aviation Regulations (FAR) Part 145 governs those facilities. Shops authorized under FAR Part 145 can perform maintenance, inspection and alteration on aircraft and aircraft products, and the FAA issues them an Air Agency Certificate.

Earning that certificate requires an FAA evaluation of the station's programs and systems against federal standards. Because vetting occurs before the first job arrives, an airline sending a flight computer out for post-upset diagnostics can start from a documented level of capability.

Part 145 is one of several routes to return-to-service approval. Section 43.7 states that a repair station certificate holder may approve aircraft for return to service as provided in Part 145. The same section also grants comparable authority to mechanics with an Inspection Authorization, to manufacturers and to air carrier certificate holders.

Repair Station Clearance Reshapes Aircraft on Ground (AOG) Maintenance Scheduling

An aircraft under suspicion after a solar event needs to stay on the ground until diagnostics, recalibration and certified sign-off all finish. For AOG planners, a slip at any link pushes back the release time and can force tail swaps, rotation changes and slot reassignments.

Location can also add a step of its own. When the nearest Part 145 station sits at another airport, a special flight permit under Section 21.197 can cover a flight to a maintenance base for an aircraft that falls short of airworthiness requirements yet remains safe to fly. Securing that permit may come before any diagnostic work begins.

Section 145.203 lets a certificated repair station temporarily transport personnel and equipment to another location when the FAA identifies a special circumstance. This also applies when the work recurs and the station's manual already holds the procedures. Where that option exists, AOG planners can gain room to sequence diagnostics around fleet commitments.

Preparing Maintenance Operations for an Active Solar Cycle

Should solar activity intensify, post-event diagnostics, sensor recalibration and repair station clearance can settle into the regular rhythm of maintenance planning. Carriers that line up Part 145 partners in advance, document their verification steps and build slack into rotations can meet the first alert with a plan already in hand. By understanding how a single-event upset moves from an invisible glitch to a grounded aircraft, maintenance teams can treat certified diagnostics and recalibration as safeguards rather than setbacks.