Category Archives: Aviation Safety / Air Crashes

That Time An X-15 Rocket Plane Entered Hypersonic Spin At Mach 5 And Broke Apart Killing USAF Test Pilot.

U.S. Air Force test pilot Maj. Michael J. Adams was killed during X-15 Flight 191 on Nov. 15, 1967.

The North American X-15 was a hypersonic rocket-powered aircraft 50 ft long with a wingspan of 22 ft. operated by the United States Air Force and the National Aeronautics and Space Administration as part of the X-plane series of experimental aircraft in the 1960s.

It was a missile-shaped vehicle with an unusual wedge-shaped vertical tail, thin stubby wings, and unique side fairings that extended along the side of the fuselage. It was powered by the XLR-99 rocket engine, manufactured by Thiokol Chemical Corp., pilot-controlled and  capable of developing 57,000 lb of thrust.

The aircraft was brought to the launch altitude of 45,000 feet by a NASA B-52 “mothership” then air dropped to that the rocket plane would have enough fuel to reach its high speed and altitude test points. Depending on the mission, the rocket engine provided thrust for the first 80 to 120 sec of flight. The remainder of the normal 10 to 11 min. flight was powerless and ended with a 200-mph glide landing.

The X-15 was air dropped by a NASA B-52 “mothership”

The X-15 was capable of climbing to the edge of space at an altitude in excess of 300,000 feet at speed of more than 4,500 miles per hour (+7,270 km/h). Actually, the target altitude for X-15 flights was set at 360,000 feet because there were concerns about the reentry from 400,000 feet, that was the maximum altitude the rocket plane was theoretically able to reach.

Two types of flight profiles were used during test flights depending on the purposes of the mission: a high-altitude flight plan that called for the pilot to maintain a steep rate of climb, or a speed profile that called for the pilot to push over and maintain a level altitude.

For flight in the dense air of the usable atmosphere, the X-15 used conventional aerodynamic controls but to maneuver in the thin air outside of the appreciable Earth’s atmosphere, where flight control surfaces were useless, the X-15 used a reaction control system (RCS) made of hydrogen peroxide thrust rockets. Those located on the nose of the aircraft provided pitch and yaw control; those on the wings provided roll control. A similar system was used on the Space Shuttle Orbiter, decades later: indeed, experience and data gathered from the X-15 program contributed to the development of the Mercury, Gemini, Apollo and Space Shuttle manned spaceflight programs.

Cutaway drawing of the North American X-15.
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Needless to say, handling the rocket-powered aircraft at the edge of space was particularly challenging.

 

X-15-3 (56-6672) made 65 flights during the program. It reached attaining a top speed of Mach 5.65 and a maximum altitude of 354,200 feet.

Official records say that only 10 of the 12 X-15 pilots flew Ship #3; eight of them earned their astronaut wings during the program (in fact, U.S. Air Force pilots who flew the X-15 to altitudes above 50 miles all received Astronaut Wings): Robert White, Joseph Walker, Robert Rushworth, John “Jack” McKay, Joseph Engle, William “Pete” Knight, William Dana, and Michael Adams all earned their astronaut wings in Ship #3.

Out of three X-15s built by North American for the program, Ship #3 is the only X-15 that has not survived, as it was lost on Nov. 15, 1967.

X-15-1, serial number 56-6670, is now located at the National Air and Space museum, Washington DC. North American X-15A-2, serial number 56-6671, is at the United States Air Force Museum, Wright-Patterson AFB, Ohio.

Here’s the story of that last mission:

On 15 November 1967, Ship #3 was launched over Delamar Lake, Nevada with Maj. Michael J. Adams at the controls. The vehicle soon reached a speed of Mach 5.2, and a peak altitude of 266,000 feet.

During the climb, an electrical disturbance degraded the aircraft’s controllability. Ship #3 began a slow drift in heading, which soon became a spin. Adams radioed that the X-15 “seems squirrelly” and then said “I’m in a spin.”

Through some combination of pilot technique and basic aerodynamic stability, Adams recovered from the spin and entered an inverted Mach 4.7 dive. As the X-15 plummeted into the increasingly thicker atmosphere, the Honeywell adaptive flight control system caused the vehicle to begin oscillating. As the pitching motion increased, aerodynamic forces finally broke the aircraft into several major pieces.

Adams was killed when the forward fuselage impacted the desert. This was the only fatal accident during the entire X-15 program.  The canopy from Ship #3, recovered during the original search in 1967, is displayed at the San Diego Aerospace Museum, San Diego, California.

Parts of the crashed X-15-3, serial number 56-6672, recovered in 1992 by Peter Merlin and Tony Moore (The X-Hunters) are on display at the Air Force Flight Test Center Museum at Edwards.

According to NASA, the X-15s made a total of 199 flights over a period of nearly 10 years (from June 1959 to Oct. 1968) and set world’s unofficial speed and altitude records of 4,520 miles per hour or Mach 6.7 (set by Ship #2) and 354,200 feet (set by Ship #3).

Image credit: NASA

First Prototype Of Brazilian KC-390 Military Cargo Aircraft Almost Crashed During Stall Tests Last Month

Pilots of the KC-390 were only able to recover the aircraft 300 meters from the ground.

Embraer has grounded the first prototype of the new KC-390 military cargo jet after a stall test incident on Oct. 12. According to the Brazilian planemaker, the scheduled test pushed the aircraft beyond its operating limits, however Brazilian Aero Magazine media outlet, that has talked to an engineer involved in the project who asked to remain anonymous, something else happened in the skies near Embraer Unidade Gavião Peixoto Airport, the private airport located near Gavião Peixoto, Brazil, owned and operated by Embraer: an incident that almost ended in a tragedy.

As reported by Aero Magazine, the KC-390 registered PT-ZNF was performing critical pre-stall tests, that involved high-AOA (Angle Of Attack) and  ice formation on wings. During the maneuver, an equipment used for the tests, detached from its place and rolled to the back of the cargo compartment causing a sudden change in the center of gravity (CG) of the aircraft. As a consequence of the rapid displacement of the CG the pilots lost control of the airlifter, that stalled and started to spin towards the ground. Reportedly, the pilots were able to recover the aircraft as it was only 1,000 feet (about 300 m) above the ground, and landed the KC-390 safely in Gavião Peixoto airfield.

Analysis of the track based on the KC-390 ADS-B transponder using the popular Flightradar24.com plane-tracking website suggests that the cargo prototype plunged from about 20,000 feet to around 3,000 feet, between 13.25UTC and 13.28UTC, with a peak vertical speed of -30,976 fpm. However, based on the ADS-B raw data, the area where the test flight was taking place is not covered by receivers at altitudes below 2,800 feet, therefore it is possible that the aircraft was recovered well below 3,000 ft and that the transponder signal was detected once the aircraft had climbed again to a safe altitude after recovering from the spin.

The track followed by the KC-390 during Oct. 12 test flight. Note the vertical speed of about -31,000 fpm at 11,375 ft.

Two KC-390 prototypes have been built, the second one being example PT-ZNJ that made its first flight on Apr. 28, 2016. PT-ZNF made its maiden flight on Feb. 3, 2015.

H/T Jaime Maia for the heads-up

Taiwanese Mirage 2000 Missing Off Northeastern Taiwan Coast

Taiwanese C-130 and S-70C Aircraft Join Search with Three Ships at Crash Scene.

A Republic of China Air Force (ROCAF) Mirage 2000 from the 499th Tactical Fighter Wing based at Hsinchu Air Base on northwestern tip of Taiwan has gone missing according to news outlets and ROCAF statements.

Contact with the aircraft was reported as lost at 6:43 PM local time on Nov. 7, 2017 according to Focus Taiwan news group. The media outlet reports the aircraft was flying a routine training sortie. The aircraft was approximately 90 miles northeast of Keelung, Taiwan when it disappeared.

Following the loss of communications with the Mirage 2000, 17 aircraft are reported to have joined in a search and rescue operation including C-130 Hercules multi-engine fixed wing aircraft and S-70C search and rescue helicopters. Launch time for the search and rescue effort is reported as 7:05 PM local time. The time of sunset in the region is reported as 5:09 PM local.

The aircraft was being flown by Taiwanese Captain Ho Tzu-yu according to press reports in Chinese media. Capt. Tzu-yu is a Taiwanese Air Force Academy graduate from 2013 with over 713 hours of flight time, 491 in the Mirage 2000.

According to a statement in the South China Morning Post, Taiwanese Air Force Deputy Chief, Lieutenant General Chang Che-ping told media, “We hope Ho can be safely rescued soon.”

The Mirage 2000 is a single-engine delta-wing multirole tactical aircraft first flown in 1978 and built by the French Dassault corporation. It is operated by nine air forces around the world. Reports indicate five accidents involving Mirage 2000 aircraft in service with Taiwan between 1999 and 2013. Three accidents were fatal. The aircraft were temporarily grounded in 2012 following a fatal training accident of a Taiwanese pilot in France. Taiwan is reported to have purchased 60 of the aircraft in 1992. Production for the Mirage 2000 ended in 2007.

Capt. Ho Tzu-yu’s unit, the 499th Tactical Fighter Wing, contains three active squadrons, the 41st, 42nd and 48th Squadrons. It is the only Taiwanese unit to operate the Mirage 2000.

Taiwan’s Coast Guard and Navy are reported to have sent 10 surface vessels to the area to assist in the search and rescue effort. Taiwan media also reports that all Mirage 2000 aircraft have been temporarily grounded following the accident.

Top image credit: Toshiro Aoki – http://jp-spotters.com/7600LL.html

Yemen’s Houthi Rebels Claim They Have Shot Down A Saudi Eurofighter Typhoon Over Yemen

Yemeni media outlets are reporting that a Royal Saudi Air Force Typhoon was shot down over Yemen yesterday. However no pictures have been released to back Houthi rebels claims, so far.

According to several still unconfirmed media reports, a RSAF Typhoon fighter was shot down by Yemen’s Shia Houthi rebels on Oct. 27. The fate of the pilot is unknown at the time of writing. No images of the wreckage or any other kind of evidence have been released so far.

“Yemen’s air defense unit told the country’s Arabic-language al-Masirah television network that the aircraft had been targeted with a surface-to-air missile as it was flying in the skies over Nihm district east of the Yemeni capital city of Sana’a on Friday evening,” Yemen Press reported.

For the moment there haven’t been comments by the Saudi-led coalition over the Houthi claims. Still, Saudi sources, including popular Saudi military aviation expert @MbKS15, deny the accident has occurred, saying it’s just propaganda.

Earlier this month, on Oct. 1, a U.S. MQ-9 Reaper drone was shot down over Sanaa: footage filmed from several different locations (the UAV was over the capital in daylight conditions when it was destroyed) depicted the incident from start to finish.

If confirmed, this would be the second Saudi Typhoon lost over Yemen while supporting Operation Decisive Storm, the Saudi-led air war on the Houthi rebels in the southern end of the Arabian Peninsula: indeed, a RSAF Eurofighter crashed into a mountain in Al Wade’a district on Sept. 13. Back then, the cause of the crash was an alleged technical failure during a CAS (Close Air Support) mission. The pilot, identified as Mahna al-Biz, died in the accident.

Anyway, provide the reports are accurate and a Typhoon has really been shot down, the accident would be the fourth crash of a Eurofighter jet in one a a half months: along with the already mentioned RSAF Typhoon combat aircraft that crashed in Yemen on Sept. 13, 2017, on Sept. 24, an Italian Air Force Typhoon crashed into the sea while performing its solo display during the Terracina airshow killing the test pilot, whereas on Oct. 12, a Spanish Air Force Eurofighter crashed into the ground while returning to Albacete after taking part in the National Day Parade over Madrid.

We will update this post as soon as new official details/confirmation/denial emerge.

Top image credit: Alessandro Fucito

Israeli Air Force F-35I “Adir” Involved In A Bird Strike Incident Gets Grounded

An Israeli Air Force F-35 has been involved in a bird strike during a training sortie. And the incident has fueled some weird speculations…

An Israeli Air Force F-35I “Adir” (Mighty) was involved in a bird strike incident during a training sortie two weeks ago, the Israeli Defense Forces said on Oct. 16. The pilot managed to land the plane safely back at Nevatim Air Force Base in the Negev Desert and no casualties were reported.

This is the first incident to an F-35 in IAF service since the first two aircraft have been taken on charge by the 140 “Golden Eagle” squadron in December last year.

The IDF confirmed those details to Israeli media outlets: “During a training sortie two hits were found on the plane, following to a collision with a bird. After an evaluation and assessment of the damage conducted together with the manufacturer – Lockheed Martin, the plane was sent to a normal maintenance and repair. It will return to full service in the next few days.”

Seven “Adir” aircraft have been delivered to the Israeli Air Force since December 2016. In August, a deal was completed for the purchase of another 17 such aircraft: therefore 50 such aircraft will be operated by the IAF equipping two squadrons. The total amount of the deal to purchase the 50 aircraft is estimated at 6B USD.

Meanwhile, the Golden Eagle Squadron continues to perform a wide array of flight tests to verify the 5th generation aircraft capabilities. The Squadron is scheduled to become operational by the end of this year.

The news of the birdstrike incident was released on the very same day the Israeli targeted a Syrian SAM battery that had attacked IDF aircraft during a routine flight over Lebanon fueling speculations that the F-35 was not grounded by a birdstrike but because it was hit by the Syrian air defenses. In fact, the Syrian Defense Ministry said in its statement that government forces responded to the violation of the airspace and “directly hit one of the jets, forcing [Israeli aircraft] to retreat.” On the other side the Israeli denied any aircraft was hit by the Syrian air defenses (S-200 battery) and this sounds quite reasonable considered that the Israeli have often shown their ability to operate freely in the Syrian airspace and there would have been no reason to disclose a fake birdstrike at all to cover a Syrian hit.

Image credit: Author

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