Board of Audit of Japan Warns Many MSDF P-1 Patrol Planes Inoperable; Parts Shortages, Device Defects Among Causes
Some Maritime Self-Defense Force P-1 patrol planes are not operational, according to a Board of Audit of Japan report released Friday.
P-1 patrol planes are for detecting submarines and surveilling suspicious ships in the seas around Japan.
The Board of Audit said that frequent engine trouble and shortages of parts for repairs are among the causes of the planes' underutilization.
The report stated that 'a limited number of planes are mission ready' and demanded the Defense Ministry improve the situation.
Thirty-five P-1 planes had been procured as of fiscal 2023 at a total cost of about ¥1.78 trillion. The government plans to procure another 26 units before fiscal 2054, when P-1 planes are set to cease operations.
In compiling the report, the Board of Audit checked the operational conditions of P-1 planes between fiscal 2019 and 2023 and concluded that they had been underutilized because of three factors: deterioration of engine performance; defects in electronic information-gathering devices; and a chronic shortage of replacement parts.
The report stated that, in many cases, the engine deterioration and electronic device defects were caused by material erosion due to long flights over the sea. There were many cases in which such planes became unusable.
Additionally, the low utilization rate was found to be caused by delays in procuring parts due to rapid changes in the global landscape and a worldwide semiconductor shortage.
As a result, some P-1 planes have had to undergo 'cannibalistic maintenance' — in which parts of one P-1 plane are replaced with parts from others. Such units are utilized only in stopgap operations.
The Board of Audit did not disclose numerical data of the operations, names of defective devices and other details, as disclosing them could reveal the MSDF's capability to deal with contingencies.
Speaking to reporters, a Defense Ministry official said, 'We are taking the pointed-out facts seriously and will continue making efforts to maximize the operational levels [of P-1 patrol planes].'
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Asahi Shimbun
4 hours ago
- Asahi Shimbun
Key MSDF patrol aircraft not up to task as corrosion ‘eating' engines
Engine malfunctions are plaguing the fleet of patrol aircraft essential to Maritime Self-Defense Force tracking of Chinese submarines and suspect ships in Japanese waters, according to the Board of Audit. The aircraft fly over the ocean at low altitudes for hours on end, making them prone to engine corrosion. The aircraft are a mainstay in Japanese efforts to monitor China's growing maritime assertiveness. The board did not divulge how many aircraft were affected in keeping with Defense Ministry protocols on security issues. The P1, the nation's first domestically made aircraft, was initially viewed as holding huge potential. It was considered to have no peer in submarine detection and tracking technology and there was talk of exporting the aircraft. But that never got off the ground. The Board of Audit study covered the 35 P1 aircraft deployed at MSDF bases across Japan as of September 2024. Primarily manufactured by Kawasaki Heavy Industries Ltd., the first P1 was deployed in 2013. It was the successor aircraft to the P3C, made by U.S. manufacturer Lockheed Martin Corp. The Board of Audit study said development, purchase and repair costs for the P1 through fiscal 2023 came to 1.776 trillion yen ($12.3 billion). The Defense Ministry's Acquisition, Technology and Logistics Agency plans to eventually deploy a total of 61 P1 aircraft at a cost of 4.090 trillion yen. The agency knew early on about the engine corrosion issue, but IHI Corp., which oversaw development, said the malfunctions were coincidental. So, nothing was done to rectify the problem. Within the MSDF, flying the P1 is considered the 'mission of missions' in that it comes with a huge array of detection equipment, making the plane a joy to operate. Increased sightings of Chinese submarines and other vessels in waters around Japan resulted in many more P1 missions. The burden of operating the aircraft around the clock on a rotational basis was never envisaged in the development stage, according to a highly placed MSDF officer. All sorts of issues emerged early on. The technology used in the U.S.-made P3C was off-limits, so Japanese engineers had to basically develop the aircraft technology from scratch. And this was at a time when the defense budget was not nearly as massive as it is today, meaning not all aspects of development could be adequately dealt with. The 'stovepipe' structure that separated ministry bureaucrats from SDF uniformed officers led to a failure in sharing information during the development stage, according to a high-ranking Defense Ministry official. The Board of Audit also pointed out that issues with the onboard electronic equipment and weapons were another reason some of the aircraft were grounded. Hopes of exporting the P1 aircraft were dashed after one of a pair dispatched to the Paris Air Show in 2017 developed problems and could not take part. (This article was written by Wataru Netsu and Daisuke Yajima.)
Yomiuri Shimbun
5 hours ago
- Yomiuri Shimbun
Board of Audit of Japan Warns Many MSDF P-1 Patrol Planes Inoperable; Parts Shortages, Device Defects Among Causes
Some Maritime Self-Defense Force P-1 patrol planes are not operational, according to a Board of Audit of Japan report released Friday. P-1 patrol planes are for detecting submarines and surveilling suspicious ships in the seas around Japan. The Board of Audit said that frequent engine trouble and shortages of parts for repairs are among the causes of the planes' underutilization. The report stated that 'a limited number of planes are mission ready' and demanded the Defense Ministry improve the situation. Thirty-five P-1 planes had been procured as of fiscal 2023 at a total cost of about ¥1.78 trillion. The government plans to procure another 26 units before fiscal 2054, when P-1 planes are set to cease operations. In compiling the report, the Board of Audit checked the operational conditions of P-1 planes between fiscal 2019 and 2023 and concluded that they had been underutilized because of three factors: deterioration of engine performance; defects in electronic information-gathering devices; and a chronic shortage of replacement parts. The report stated that, in many cases, the engine deterioration and electronic device defects were caused by material erosion due to long flights over the sea. There were many cases in which such planes became unusable. Additionally, the low utilization rate was found to be caused by delays in procuring parts due to rapid changes in the global landscape and a worldwide semiconductor shortage. As a result, some P-1 planes have had to undergo 'cannibalistic maintenance' — in which parts of one P-1 plane are replaced with parts from others. Such units are utilized only in stopgap operations. The Board of Audit did not disclose numerical data of the operations, names of defective devices and other details, as disclosing them could reveal the MSDF's capability to deal with contingencies. Speaking to reporters, a Defense Ministry official said, 'We are taking the pointed-out facts seriously and will continue making efforts to maximize the operational levels [of P-1 patrol planes].'
8 hours ago
Japanese P-1 Patrol Aircraft Underused: Board of Audit
News from Japan Society Jun 28, 2025 13:17 (JST) Tokyo, June 28 (Jiji Press)--The Japanese Maritime Self-Defense Force's P-1 aircraft, the first domestic patrol aircraft, is underused mainly due to engine corrosion and problems with electronic devices, the government's Board of Audit has said. Reporting the outcome of its probe into the matter Friday, the board called for making the maximum use of knowledge gained from past malfunctions and conducting appropriate tests to improve the performance of the aircraft. The board stopped short of disclosing details of the low operational status, such as the number of aircraft active at present, citing national security concerns. The importance of monitoring submarines and military vessels in waters around Japan is increasing, especially after the recent close encounter incidents between Japanese patrol and Chinese military aircraft On June 7, a fighter jet based on a Chinese aircraft carrier made a dangerously close approach to an MSDF P-3C patrol aircraft monitoring the ship in the Pacific Ocean. A similar incident happened the next day. [Copyright The Jiji Press, Ltd.] Jiji Press
