US Air Force Halts Operations on E3 Fleet Amid Concerns for Structural Integrity

On Thursday, the Air Combat Command of the US service affirmed that the E-3 Sentry aerial target tracking planes had been inspected for substandard tail pins on Wednesday.

The E-3 Sentry aerial target tracking plane, which the US Air Force uses to track targets in the air, has come under scrutiny recently due to the discovery of potentially dangerous parts. Investigations have revealed that tail pins on at least two dozen aircraft across five fleets may be defective.

In the extensive search for a minute piece responsible for a plane’s tail breaking off, it has been determined that the issue is present in at least two dozen Air Force planes from five different fleets. However, the Air Force has not disclosed the exact number of aircraft that have the hazardous component.

An email from Air Force spokesperson Capt. Laura Hayden revealed that all E-3s in the field had been inspected, and most had resumed normal operations. The Air Force was unwilling to disclose how many Sentries required replacement components, though they confirmed that the amount cleared was enough to meet the daily requirements.

“The only aircraft requiring inspection are in depot maintenance and will be inspected before leaving the depot facility,” Hayden said. “No mishaps have occurred in the E-3 … as a result of non-conforming pins.”

The Air Force reported on Sunday that out of the 90 KC-135s that were inspected.

Over the past three weeks, the KC-135 Stratotanker aerial refueling fleet maintainers have examined hundreds of planes for substandard pins, and Airmen have finished their inspections. According to Brian Brackens, a service spokesperson, any pins found to be inadequate have been replaced.

“The fleet continues to meet operational requirements supporting missions around the globe, which is a testament to the skill, speed, and professionalism of our maintenance crews, engineers, and logisticians in identifying and addressing the issue and preventing any potential mishaps,” he said.

By February 14, the Air Force Times reported that 24 out of the 90 KC-135s inspected had pins that did not meet the requirements. Upon obtaining the aircraft’s correct parts, they are allowed to fly.

The AWACS fleet is located at Tinker Air Force Base in Oklahoma, Joint Base Elmendorf-Richardson in Alaska, and Kadena Air Base in Japan. The planes are easily identifiable due to their large radomes, which monitor and detect motion in the surrounding airspace.

This year, the service is reducing its 1970s-era AWACS fleet from 29 to 16 in anticipation of the new E-7 Wedgetail. The E-3s are outfitted with a Boeing 707 fuselage similar to the C-135 series employed by the Air Force.

Friday, the North Atlantic Treaty Organization (NATO) reported that they are inspecting their fleet of E-3s after the US had informed all AWACS aircraft operators, including the U.K., France, Saudi Arabia, and Japan, of the problem.

The US Air Force has given Boeing the first contract to provide a fleet of 26 E-7 aircraft. This agreement was announced on March 1, 2023. The contract for Boeing will amount to a maximum of $1.2 billion as the service works to introduce a new fleet to supplant the E-3 Sentry, which has come to be recognized.

When asked how many aircraft in total require new pins, Brackens declined to provide an answer due to the requirement of operational security.

He noted that the fleet had successfully met its operational requirements, executing missions worldwide due to the expertise, rapidity, and dedication of the maintenance personnel, engineers, and logisticians in pinpointing and remedying the issue and averting any possible accidents.

The work for three fleets that risked being affected has ended — the RC-135 set of reconnaissance aircraft, the WC-135 Constant Phoenix radiation-identifying jet, and the TC-135 training versions.

Hayden reported that the only aircraft located in the fleets with non-conforming equipment was in depot servicing. Before the planes depart, the pins will be exchanged.

The USAF owns roughly 360 KC-135 Stratotankers, which entered service in 1956, and roughly 36 RC-135 and WC-135 aircraft, all based on the same Boeing fuselage. The RC-135s was introduced in 1964, and the WC-135s followed a year later in 1965.

The United States Air Force is transitioning away from their KC-135 Stratotankers and introducing the KC-46 Pegasus. These planes are housed in 10 active duty bases and around two dozen Air Force Reserve and Air National Guard sites worldwide.

Offutt Air Force Base in Nebraska is the home base for the RC-135 and WC-135 fleets.

During every session of intensive maintenance, four pins – two on each side of the vertical stabilizer – are changed for new ones on each aircraft.

A memo on the unofficial Air Force Facebook page on February 9 revealed that the pins could have been placed during planned depot maintenance between June 2020 and December 2022. The Air Force later confirmed this memo’s validity to Defense News.

A memo reported that, in January, a metallurgical analysis of two pins that did not meet standards revealed several issues. These included being too small, crafted with an unsuitable material, and needing more plating.

The Air Force noted that should a single aircraft perform differently than intended. The consequences would be disastrous.

“Should one pin fail, the other would not be able to carry the remaining load, and the vertical stabilizer would depart the aircraft,” the memo said.