Tag Archives: Test Pilot

1 July 2015

July 1, 2025AviationBell 525 Relentless, c/n 62001, Erik Allan Boyce, First Flight, General Electric CT7-2F1, Jason Cori Grogan, Jeff Greenwood, N525TA, Prototype, Test Pilot, Troy CaudillBryan Swopes

1 July 2015: Bell Helicopter’s new medium transport helicopter, the Model 525 Relentless, N525TA, made its first flight at Bell’s assembly plant in Amarillo, Texas. Test pilots Troy Caudill and Jeff Greenwood were in the cockpit.

The Bell 525 is the first helicopter to use fly-by-wire flight controls. Side stick controllers replace the customary cyclic and collective controls. For the first time for Bell, the 525 uses a five blade main rotor and four blade tail rotor.

The helicopter is designed to be operated by two pilots and carry up to 18 passengers. It is powered by two General Electric CT7-2F1 turboshaft engines, each rated at 1,714 shaft horsepower, maximum continuous power, and 1,979 shaft horsepower for takeoff.

The Model 525 is the largest helicopter built by Bell. It has an overall length of 64.81 feet (19.75 meters) with rotors turning. The fully-articulated main rotor has a diameter of 54.50 feet (16.62 meters) and rotates counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The mast tilts forward 5°. The four bladed tail rotor is mounted on the left side of a pylon and rotates clockwise when viewed from the helicopter’s left side. (The advancing blade is below the axis of rotation.) It has a diameter of 10 feet (3.05 meters). The pylon is canted to the left at 15°. The 525 Relentless has a maximum gross weight of 20,000 pounds (9,072 kilograms).

The Model 525 has a maximum cruise speed of 160 knots (184 miles per hour/296 kilometers per hour), and maximum range of 580 nautical miles (1,074 kilometers). At its maximum gross weight the helicopter can hover in ground effect (HIGE) at 10,700 feet (3,261 meters), and out of ground effect (HOGE) at 8,100 feet (2,469 meters).

The prototype Bell 525 Relentless in cruise flight. (Bell Helicopter) — The prototype Bell 525 Relentless, N525TA, in cruise flight. (Bell Helicopter)

N525TA was destroyed during a test flight approximately 30 miles south of Arlington, Texas, 11:48 a.m., 6 July 2016. While conducting a test to determine never exceed speed (V_NE) for single-engine flight, the 525 was flying 185 knots (213 miles per hour/343 kilometers per hour) at 1,975 feet (602 meters), the main rotor blades “departed their normal plane of rotation” and struck the nose and tail. The two test pilots on board, Jason Cori Grogan and Erik Allan Boyce, were killed. Both were majors in the United States Marine Corps Reserve, assigned to HMLA 773. Each pilot was a graduate of the U.S. Naval Test Pilot School.

The National Transportation Safety Board (NTSB) determined that the Probable Cause was:

A severe vibration of the helicopter that led to the crew’s inability to maintain sufficient rotor rotation speed (Nr), leading to excessive main rotor blade flapping, subsequent main rotor blade contact with the tail boom, and the resultant in-flight breakup. Contributing to the severity and sustainment of the vibration, which was not predicted during development, were (1) the collective biomechanical feedback and (2) the attitude and heading reference system response, both of which occurred due to the lack of protections in the flight control laws against the sustainment and growth of adverse feedback loops when the 6-hertz airframe vibration initiated. Contributing to the crew’s inability to maintain sufficient Nr in the severe vibration environment were (1) the lack of an automated safeguard in the modified one-engine-inoperative software used during flight testing to exit at a critical Nr threshold and (2) the lack of distinct and unambiguous cues for low Nr.

There are currently three 525s undergoing flight testing. The Federal Aviation Administration certified the Bell 525’s CT7 engines in March 2019.

The number three Bell 525 Relentless prototype, N525BN, first flew 22 April 2016.

30 June 1968

June 30, 2025Aviation66-8303, First Flight, General Electric TF-39, Leo J. Sullivan, Lockheed C-5A Galaxy, Lockheed L-500, Lockheed-Marietta, Prototype, Test Pilot, Walter E. HensleighBryan Swopes

Lockheed test pilot Leo J. Sullivan. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

30 June 1968: At 7:47 a.m., Eastern Daylight Time, the first Lockheed C-5A Galaxy transport, serial number 66-8303, took off on its maiden flight at Marietta, Georgia. Chief Engineering Test Pilot Leo J. Sullivan and test pilot Walter E. Hensleigh, flight engineer Jerome H. Edwards, and E. Mittendorf, flight test engineer, made up the flight crew. U.S. Air Force test pilot Lieutenant Colonel Joseph S. Schiele was also on board.

The C-5A weighed 497,000 pounds (225,435 kilograms) at takeoff. After a 3,800 foot (1,158 meters) takeoff roll, it lifted off at 123 knots (142 miles per hour/228 kilometers per hour). It remained in takeoff configuration while it climbed to 10,000 feet (3,048 meters) at 140 knots (161 miles per hour/259 kilometers per hour). The flight lasted 1 hour, 34 minutes. On landing, the Galaxy’s touchdown speed was 116 knots (133 miles per hour/215 kilometers per hour).

Lockheed C-5A Galaxy during its first flight. (Code One Magazine/Lockheed Martin) — Lockheed C-5A Galaxy 66-8303 during its first flight. (Code One Magazine)

The Lockheed C-5A Galaxy (Lockheed Model L-500) is a long-range, heavy lift military transport with high, “shoulder-mounted” wings and a “T-tail.” It has a flight crew of two pilots, two flight engineers and three load masters. The airplane’s cargo compartment can be accessed by a ramp at the rear of the fuselage, and the nose can be raised to allow cargo to be loaded from the front. The wings’ leading edges are swept to 25°. Four turbofan engines are mounted on pylons beneath the wings. The landing gear has 28 wheels in five units, and can “kneel” to bring the cargo deck closer to the ground for loading and unloading.

The C-5 is a truly giant aircraft. It is 247 feet, 10 inches (75.540 meters) long with a wingspan of 222 feet, 9 inches (67.894 meters) and overall height of 65 feet, 1 inch (19.837 meters). The cargo compartment has a height of 13 feet, 6 inches (4.115 meters) and width of 19 feet (5.791 meters). It is 143 feet, 9 inches (43.825 meters) long. The C-5A has a maximum takeoff weight of 840,000 pounds (381,018 kilograms) and a maximum cargo weight of 270,000 pounds (122,470 kilograms).

A McDonnell Douglas KC-10 Extender refuels a Lockheed C-5A Galaxy. (U.S. Air Force)

The C-5A, C-5B and C-5C are powered by four General Electric TF-39 high-bypass turbofan engines, rated at 43,000 pounds of thrust, each. The C-5M uses four General Electric F138 engines rated at 51,250 pounds of thrust, each.

The Galaxy has a cruise speed of 0.77 Mach and maximum speed of 0.79 Mach. Its service ceiling is 35,700 feet (10,881 meters) and its unrefueled range is 2,400 nautical miles (3,862 kilometers).

Lockheed C-5A Galaxy 66-8304, the second airplane, during a test flight near Edwards Air Force Base, California. (U.S. Air Force)

Lockheed produced 81 C-5A Galaxy transports for the U.S. Air Force between 1969 and 1973. These were followed by 50 C-5Bs. Two C-5As were modified to C-5Cs to carry larger “space cargo.” Remaining C-5s in the fleet are being modified to an improved C-5M Super Galaxy variant.

The first prototype C-5A, 66-8303, was destroyed by and explosion and fire after being defueled at Dobbins Air Force Base, 17 October 1970. One person was killed.

An M1 Abrams Main Battle Tank on the forward cargo ramp of a Lockheed C-5 Galaxy. The transports nose has been raised to provided loading access from the front of the airplane. (U.S. Air Force) — An M1A1 Abrams Main Battle Tank being loaded on the forward cargo ramp of a Lockheed C-5M Super Galaxy. The transport’s nose has been raised to provide loading access from the front of the airplane. The tank weighs 139,081 pounds (63,086 kilograms). (Roland Balik/U.S. Air Force)

29 June 1965

June 29, 2025Aviation, Space Flight56-6672, Apollo Program, Astronaut, Delamar Dry Lake, Edwards Air Force Base, Joe Engle, Joe Henry Engle, NASA, North American Aviation Inc., North American Aviation X-15A, Reaction Motors XLR99-RM-1, Space Shuttle Program, Test Pilot, X-15, X-15 Program, X-15A-3Bryan Swopes

Captain Joe Henry Engle, United States Air Force

29 June 1965: At 10:21:17.6 PDT, Captain Joe H. Engle, United States Air Force, flying the Number Three North American Aviation X-15A-3 research rocketplane, 56-6672, was air-dropped from the NB-52B Stratofortress mothership, Balls 8, over Delamar Dry Lake in Nevada. This was the 138th flight of the X-15 Program, and Joe Engle’s 12th. He fired the Reaction Motors XLR99-RM-1 engine for 81.0 seconds and accelerated to Mach 4.94 (3,432 miles per hour, 5,523 kilometers per hour). The X-15 climbed to an altitude of 280,600 feet (85,527 meters, 53.14 miles). He touched down at Edwards Air Force Base after 10 minutes, 34.2 seconds of flight. His parents were at Edwards to witness his flight.

Captain Engle qualified for Astronaut wings on this flight, the third and youngest Air Force pilot to do so.

Command Pilot Astronaut insignia, United States Air Force

From 1963 and 1965, Joe Engle made 14 flights in the three X-15s. After leaving the X-15 Program, he was assigned to the Apollo Program, the only NASA astronaut with prior spaceflight experience. He was the back-up Lunar Module pilot for Apollo 14 and he was the designated LM pilot for Apollo 17 but was replaced by Harrison Schmidt when Apollo 18 was cancelled. Next he went on to the Space Shuttle Program. He was a Mission Commander for the Enterprise flight tests and for Columbia‘s second orbital flight, during which he became the only pilot to manually fly a Mach 25 approach and landing. Finally, he commanded the Discovery STS 51-1 mission.

Joe Engle retired from the Air Force in 1986. He was then promoted to the rank of Major General and assigned to the Kansas Air National Guard. He has flown at least 185 aircraft types and accumulated 14,700 flight hours, with 224 hours in space.

Captain Joe H. Engle, U.S. Air Force, with the North American Aviation X-15A-2, 56-6671, at Edwards Air Force Base, California, 1965. (NASA)

27 June 1963

June 27, 2025Aviation, Space Flight52-008, 56-6672, Astronaut, Balls 8, Bob Rushworth, Boeing Airplane Company, Boeing NB-52B Stratofortress, Delamar Dry Lake, Edwards Air Force Base, Manned Space Flight, North American Aviation Inc., North American Aviation X-15A, Reaction Motors XLR99-RM-1, Robert A. Rushworth, Stratofortress, Test Pilot, X-15Bryan Swopes

27 June 1963: At 09:56:03.0 PDT, Major Robert A. Rushworth, United States Air Force, flying the Number Three North American Aviation X-15 research rocketplane, 56-6672, was air-dropped from the NB-52B Stratofortress mothership, Balls 8, over Delamar Dry Lake in Nevada.

This was the 87th flight of the X-15 Program, and Bob Rushworth’s 14th.

North American Aviation X-15 56-6672 immediately after being dropped by the Boeing NB-52 Stratofortress. (NASA)

Rushworth fired the Reaction Motors XLR99-RM-1 engine for 80.1 seconds and accelerated to Mach 4.89 (3,425 miles per hour, 5,512 kilometers per hour). The X-15 climbed to an altitude of 285,000 feet (86,868 meters, 53.98 miles). Rushworth touched down at Edwards Air Force Base after 10 minutes, 28.0 seconds of flight.

Major Rushworth qualified for Astronaut wings on this flight, the second X-15 pilot to do so.

From 1960 and 1966, Bob Rushworth made 34 flights in the three X-15s, more than any other pilot.

27 June 1952

June 27, 2025Aviation46-011, 46-675, B-50A-5-BO, Bell Aircraft Corporation, Bell X-2, Boeing B-50A Superfortress, Curtiss-Wright Corporation, Curtiss-Wright XLR25-CW-1, Edwards Air Force Base, First Flight, Jean LeRoy Ziegler, NACA, National Advisory Committee for Aeronautics, Rocketplane, Skip Ziegler, Test PilotBryan Swopes

27 June 1952: The Bell X-2 research rocketplane, with company test pilot Jean Leroy (“Skip”) Ziegler at the controls, was airdropped from a “mothership,” a Boeing B-50A-5-BO Superfortress, 46-011, over Edwards Air Force Base, California. This was the first flight of the X-2 Program, and was an unpowered glide flight for pilot familiarization.

On touch down, the nose wheel collapsed and the aircraft slid across the dry lake bed, but was not seriously damaged.

Two X-2 rocketplanes, serial numbers 46-674 and 46-675, were built by the Bell Aircraft Corporation, which has also built the X-1 series. The second X-2 was the first one to fly.

Bell Aircraft Corporation test pilot Jean Leroy (“Skip”) Ziegler standing next to the Bell X-2 rocket plane on Rogers Dry Lake, California, after the first glide flight, 27 June 1952. The nose wheel collapsed on landing. (NASM)

The X-2 was a joint project of the U.S. Air Force and NACA (the National Advisory Committee for Aeronautics, the predecessor of NASA). The rocketplane was designed and built by Bell Aircraft Corporation of Buffalo, New York, to explore supersonic flight at speeds beyond the capabilities of the earlier Bell X-1 and Douglas D-558-2 Skyrocket. In addition to the aerodynamic effects of speeds in the Mach 2.0–Mach 3.0 range, engineers knew that the high temperatures created by aerodynamic friction would be a problem, so the aircraft was built from Stainless Steel and K-Monel, a copper-nickel alloy.

The Bell Aircraft Corporation X-2 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 32 feet, 3 inches (9.830 meters) and height of 11 feet, 10 inches (3.607 meters). Its empty weight was 12,375 pounds (5,613 kilograms) and loaded weight was 24,910 pounds (11,299 kilograms).

Bell X-2 46-675 on its transportation dolly at Edwards Air Force Base, california, 1952. (NASA) — Bell X-2 46-675 on its transportation dolly at the NACA High Speed Flight Station, Edwards Air Force Base, California, 1952. (NASA)

The X-2 was powered by a throttleable Curtiss-Wright XLR25-CW-1 rocket engine that produced 2,500–15,000 pounds of thrust burning alcohol and liquid oxygen. Rather than use its limited fuel capacity to take off and climb to altitude, the X-2 was dropped from a modified heavy bomber as had been the earlier rocketplanes. The launch altitude was 30,000 feet (9,144 meters). After the fuel was exhausted, the X-2 glided to a touchdown on Rogers Dry Lake at Edwards Air Force Base.

A four-engine Boeing B-50A Superfortress bomber, serial number 46-011, was modified as the ”mothership.” A second Superfortress, B-50D-95-BO 48-096, was also modified to carry the X-2, and was redesignated EB-50D. During the flight test program, the X-2 reached a maximum speed of Mach 3.196 (2,094 miles per hour, 3,370 kilometers per hour) and a maximum altitude of 126,200 feet (38,466 meters).

On 12 May 1953, less than one year after the first glide flight, Skip Ziegler was in the cockpit of 46-675 while it was being carried on a captive test flight aboard the B-50A Superfortress. An internal explosion destroyed the X-2 and killed Ziegler and another crewman aboard the mothership. The rocketplane fell into Lake Ontario and neither it nor Ziegler’s body were ever recovered. The Superfortress was able to land, but was so badly damaged that it never flew again.

Jean L. "Skip" Ziegler, with the Bell X-5 at Edwards Air Force Base, 1952. (LIFE Magazine via Jet Pilot Overseas. — Jean Leroy “Skip” Ziegler, with the Bell X-5 at Edwards Air Force Base, 1952. (LIFE Magazine via Jet Pilot Overseas.)

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