Ukraine Investigating Potential Causes of the Crash of an F-16

Ukraine is investigating the crash this week of one of the few F-16 fighter jets that had been delivered to the country by its allies in NATO, and was already collaborating with the United States to try to determine what happened, the head of Ukraine’s air force said on Friday.

At the same time, a Western official who has been briefed on the preliminary investigation said that there are “indications” that friendly fire from a Patriot missile battery might be involved in the crash.

The plane crashed on Monday while defending against an intense aerial attack by Russian forces, which on Thursday hit an apartment block in Ukraine’s second largest city, Kharkiv, killing five and wounding scores more.

The United States has supplied Ukraine with Patriots, which include a powerful radar system and mobile launchers that fire missiles at incoming projectiles, and the Ukrainian military has used them frequently as part of its defense against Russian aerial attacks.

One possibility being explored is whether a Patriot battery might have accidentally fired at the plane, the official said. A second possibility is system malfunction.

Ukraine took delivery of half a dozen F-16’s just a few weeks ago, the first of a total of 45 promised by its allies in Europe. The loss of one so soon after their arrival is a significant blow to Ukraine’s effort to integrate the aircraft into its war effort, and to convince NATO allies that it can efficiently handle sophisticated western weapons.

The pilot of the plane, Lt. Col. Oleksiy Mes, died in the crash. He was one of only about a dozen Ukrainians who had been through an accelerated training programs before going into battle, an element of added risk, experts said.

The F-16’s, as well as other aspects of U.S. military aid to Ukraine, promised to be on the table at a scheduled meeting in Washington on Friday between the American defense secretary, Lloyd J. Austin III, and Ukraine’s minister of defense, Rustem Umerov.

The aircraft, delivered after many months of pressure by President Volodymyr Zelensky of Ukraine and other senior officials, are the most high-profile piece of military hardware supplied by the country’s allies since Russia launched its full-scale invasion of the country 30 months ago.

As such, they have become a symbol of Ukraine’s defense and their pilots were considered by many people to be national heroes.

“We will find out the causes of the air disaster,” said the commander of the Ukrainian Air Force, Lt. Gen. Mykola Oleschuk, in a post on the Telegram social media app on Friday. “We have to thoroughly understand what happened, the circumstances, and whose responsibility it is.”

In a statement on about the crash on Thursday, the Air Force said only that “communication was lost” with the plane, leaving unclear whether it had been shot down or was a victim of mechanical failure, pilot error or another factor. The Air Force also said that F-16’s had shot down four Russian cruise missiles.

Ukrainians have placed great faith in the potential battlefield impact of F-16’s, which are better equipped for both defensive and offensive operations than the fleet of Soviet-era aircraft that Ukraine’s Air Force has been using. But military experts have cautioned that it could take years before enough of the planes are been delivered — and enough pilots and ground crews trained — for their full impact to be felt.

A recent report by the Center for Strategic and International Studies, a think tank based in Washington, said that it should be possible for Ukraine to start to use the aircraft to hit ground targets. But the report cautioned that it “will be years before the Ukrainian Air Force has enough experience to execute combat missions effectively.”

The nationwide missile and drone strike on Monday was one of the largest since the start of Russia’s full-scale invasion. Moscow followed up with another barrage on Tuesday and a smaller one on Thursday. In addition, Russia has also pummeled frontline areas in eastern Ukraine.

On Thursday, a Russian glide bomb hit a mid-rise apartment block in Kharkiv, the head of the regional military administration, Oleh Syniehubov, said in a post on the Telegram social media app. Mr. Syniehubov said the strike would not have succeeded if Ukraine had adequate air defenses. He later said that six people had been killed and dozens of others wounded.