SPOKANE, Wash. -

A year after three Naval aviators perished in the crash of their EA-6B Prowler in a rural area 50 miles west of Spokane, a crash report has found pilot error was the likely cause of the loss of the aircraft on March 11, 2013.

Lt. JG. Valerie Cappelaere Delaney, 26, Lt. JG. William Brown McIlvaine, 24, and Lt. Commander Alan Patterson, 34, were killed when their Prowler crashed between Harrington and Odessa during a two-ship training flight on March 11, 2013.

The aviators were assigned to Electronic Attack Squadron 129 (VAQ-129), a fleet training squadron that instructs Navy and Marine Corps aviators in flight operations in both the EA-6B Prowler and the EA-18G Growler at Whidbey Island Naval Air Station.

The report, released by the public affairs office for Commander, Naval Air Force, U.S. Pacific Fleet in San Diego, is a Manual of the Judge Advocate General (JAGMAN), which is done concurrently with the aircraft mishap safety investigation. The purpose of the JAGMAN was to determine the cause of the crash.

The investigation found the likely cause of the crash was pilot error which resulted in the controlled flight of the Prowler into the ground, killing Delaney, McIlvane and Patterson. There was no material defect of the aircraft that contributed to the crash.

The Prowler was part of a two-ship training flight that had originated at Whidbey Island Naval Air Station and was running a route across Eastern Washington at the time of the mishap when the aircraft crashed into the ground, killing Delaney, McIlvane and Patterson instantly.

The investigation found that Lt. JG. Delaney, prior to the mishap, had received a Navy Standard Score of 44.5 with five unsatisfactory flights since reporting to VAQ-129 for flight training. A score of 50 is considered average. Furthermore, remarks in her training jacket indicated she had difficulty with formation and low-level flying, receiving below average marks for both. She had also been marked as "incomplete" for her initial carrier qualifications.

In one of her final flights before the mishap, called a PF-15, conducted on January 3, her training flight was terminated due to an emergency procedure in Delaney's aircraft. The record indicated she continued to experience difficulty with formation flying at low altitudes. The March 11 flight was her second attempt at the PF-15, and had been preceded by two days of on the ground instruction with an instructor pilot on formation flying at low altitudes. Prior to March 11, she had conducted 45 flights as a fleet replacement pilot, with six formation flights and three low-level flights in the Prowler.

LCDR Patterson, the instructor pilot who would be flying with Delaney and McIlvane, was not made aware of Delaney's previous problems with low level or formation flying until the morning of the flight, when he queried the flight lead -- the pilot in command of the lead aircraft for the training flight -- while they were suiting up for the mission. The report indicates he was given a brief description about her flight history.

The flight took off from Whidbey at 8:10 a.m. and began heading eastbound, reaching the route -- designated VR 1351 -- at 8:30 a.m. Upon entry into the route, the flight lead -- Puget 2 -- set the formation to 1,000 feet above ground in a combat spread and began running the formation through a series of turns with Delaney at the controls in the wingman aircraft, designated Puget 3. Puget 2 began leading the formation through a series of turns, which Delaney recognized and adjusted her position in the flight accordingly. At the fourth turn, Puget 2 was unable to spot Puget 3 immediately and then found their position was significantly lower to the ground, nose over and over-banked. Puget 2 immediately checked his instruments to make sure his aircraft was aligned correctly and then turned back to observe just as Puget 3 hit the ground at a 30-degree nose down angle and a 90 to 100 degree bank angle. Puget 2 immediately gained altitude and declared an emergency.

One small explosion was observed by Puget 2 a moment before the aircraft hit the ground; the investigation determined that McIlvane fired his ejector seat just before impact but was halted by the aircraft impacting the ground. His remains and ejector seat were found 50 feet from the impact site.

Neither Delaney nor Patterson attempted to eject.

The crash investigation determined that the low altitude and high bank angle of the aircraft were such that the aircrew was outside the safe envelope for ejection from the aircraft.

In its opinions on the flight, the Navy found that Delaney and McIlvane were qualified to participate in the training mission on March 11, 2013. The Navy found that while Delaney was very conscientious and hard working, and had developed the respect and admiration of her peers and instructors, she lacked the proficiency to safely execute the training mission on March 11 and, in fact, a closer examination of previous grades on training missions prior to the mishap flight indicate that "should have been sufficient to halt her training" and that she should "have been given remedial training prior to commencing with the remainder of her syllabus."

However, the findings also determined that while Patterson, the instructor pilot on the mishap aircraft, was authorized to perform instructor duties, he lacked adequate proficiency to safely execute the mishap training mission due to the fact that he had been back in the cockpit for a little over a month prior to the crash, had participated in a truncated training syllabus to be qualified as an instructor pilot, and while rated as an above average pilot with "vast previous experience" he had not had enough time to train and hone the necessary skills required "to safely execute a dynamic flight with a struggling student."

Furthermore, the Navy criticized his instructor training, saying that it presented a "false endorsement of his proficiency" and the lack of flight summaries on his grade sheets for his training flights suggested an "apathetic approach" to his training with a "check in the box" mentality applied to his training by his instructors. It was only his third low-level training mission in 30 months and his first with a student since returning to VAQ-129.

In its conclusion, Navy officials determined the aircraft was in working order with no mechanical defects and the pilot was in control of the aircraft when it flew into the ground, that witnesses observed no changes to the flight profile to recover the aircraft were made until just prior to impact and that there were no communications from Puget 3 indicating they were in trouble before impact. Navy officials indicated all three perished in the line of duty and not due to misconduct and, furthermore, there was no supervisory negligence that was causal to the crash.

The Navy did issue several recommendations to the VAQ-129 leadership, including the recommendation to make immediate changes to their standard operating procedures for instructor qualification and the removal of an accelerated syllabus to fast track instructors into the pipeline to getting them into the air with pilots in the fleet replacement training program.