Accidents and incidents involving the JAS 39 Gripen

A Gripen aircraft at the Farnborough Airshow in 2006.

The JAS 39 Gripen is a fighter aircraft manufactured by the Swedish aerospace company Saab.

Eight Gripens were destroyed in crashes, two of them before the delivery to the Swedish Air Force. These aircraft included one prototype, one production aircraft and three in service with the Swedish Air Force. Two Gripens in service with the Hungarian Air Force, and one in service with the Royal Thai Air Force, were also destroyed in crashes. In addition, one aircraft was lost in a ground accident during an engine test, for a total of nine hull losses.

Crashes during testing

A sculpture in stainless steel by Thomas Qvarsebo, depicting a paper plane with a crumpled nose, has been placed on the spot of the 1993 crash.

February 1989

On 2 February 1989, the first prototype JAS 39-1 crashed on its sixth flight, when attempting to land in Linköping. The accident was filmed in a now famous recording by a crew from Sveriges Television's news program Aktuellt.[1] The pilot, Lars Rådeström, remained in the tumbling aircraft, and escaped with a fractured elbow and some minor injuries. The crash was the result of pilot-induced oscillation (PIO). Extremely gusty winds also contributed. The accident investigation committee later concluded that the problem was software related.[2][3]

August 1993

On 8 August 1993, a production JAS 39A Gripen (serial number 39-102[2]) crashed on the central Stockholm island of Långholmen, near the Västerbron bridge, when the aircraft stalled after a slow speed manoeuver during a display over the Stockholm Water Festival. The crash was, like the first one, caused by pilot-induced oscillation, and caught on film. The problem was later identified as the same software malfunction in the flight control system as the one in the crash 1989 and was corrected as late as 1995.[4][5] The pilot – Rådeström again – ejected from the aircraft, and landed safely by parachute, though he became stuck in a tree. The aircraft fell to the ground and caught fire on impact. Despite large crowds of onlookers, only one person on the ground was injured,[lower-alpha 1] and the fire was soon put out.

The aircraft had been delivered to the Swedish Defence Materiel Administration in June, only two months prior to the crash.[2] The display flight was not classified as in-service, because it was being flown at a display by a test pilot, rather than a Swedish Air Force officer.

Crashes in service

Swedish Air Force

September 1999

On 20 September 1999, a JAS 39A Gripen (serial no 39-156[2]) from Airwing F 7 Såtenäs crashed into Lake Vänern during a dogfight exercise. After passing through the wake vortex of the other aircraft, the aircraft abruptly changed course, and the pilot, Capt. Rickard Mattsson,[2] got a highest-severity warning from the ground-collision warning system. He ejected from the aircraft, and landed safely by parachute in the lake, where his colleague observed him getting into the inflatable life raft. He was picked up by a rescue helicopter 27 minutes later.

The Swedish Accident Investigation Board (SHK) could not fully determine the cause of the crash until the black box was found some 15 months later. The preliminary report is available in English.[7]

SHK's final report – not available in English – concluded that the plane had passed through the other aircraft's wake vortex while in a steep (−70 degrees) dive. When passing, the pilot's pitch command was "up", but instead the vortex inflicted a large aerodynamic transient on the aircraft, throwing it down into an almost vertical (−85 degrees) dive. These factors combined to create an angle of attack that was too large for the command to be obeyed, and so the ground-collision warning system alerted the pilot that a turn to avoid a crash would require more than 10 g. The pilot elected to vacate the aircraft in accordance with the flight manual. At the same moment the vortex effect ceased, reducing the angle of attack to within flyable limits. Although the aircraft could theoretically have been saved, the ejection sequence had already been initiated and could not be stopped.

The flight status at the moment of ejection was: altitude 750 m, flight angle −75 degrees, speed 350 km/h, angle of attack −8 degrees, and load −1.5 g.[8]

June 2005

On 1 June 2005, a JAS 39A Gripen (serial no 39-184) from Airwing F 17 Kallinge, when acting as a target in a dogfight exercise, apparently ceased to obey commands from the pilot, LtCol Axel Nilsson. After attempting to regain control while the aircraft slowly descended, the pilot ejected from the aircraft and landed safely by parachute.

SHK's investigation – report published in June 2007 – showed that the aircraft initially travelled at Mach 0.6 in a shallow dive at an altitude of 5500 m. When attacked, the pilot, not fully aware of the rather low speed, tried to escape by taking the plane into a steep (60 degrees) climb. This led to a "low speed"-warning, for which the pilot tried to compensate by lighting the afterburner and manoeuvering into an offset looping, briefly applying maximum angle of attack. The intent was to regain speed at the top of the loop. The speed was too low, and the aircraft ended up in an inverted (upside-down) deep stall, and started to descend slowly. The inadequate response to the low-speed warning may have been due the flight manual being unclear, and to the pilot being out of practice after flying a low number of flight hours per year.

When the airplane is stalled, the flight control software enters an automatic recovery mode which automatically tries to roll level, cancel spin, and reduce angle of attack. However, this mode can not handle deep stalls. Theoretically, the pilot could have recovered by disabling the automatic mode to directly control the flight control surfaces (direct link mode), and then executing a "pitch rock" maneuver. But such a recovery maneuver is not part of ordinary pilot training; the direct link mode was only intended for use by test pilots. Ultimately the pilot had to abandon the aircraft.[9]

April 2007

On 19 April 2007, a JAS 39C Gripen (serial no 39-259) from Airwing F 21 Luleå crashed at the Vidsel airfield in northern Sweden.[10] The pilot, Capt. Stefan Kaarle, was involuntarily ejected out of the aircraft in mid-air while approaching the airstrip in order to land. He landed safely by parachute. All C/D Gripens were temporarily grounded. The ejection seat handle – placed between the pilot's thighs – had been activated by the motions of the pilot's flight suit. Repeated jerks on the handle, resulting from the G-suit inflating and deflating during the flight, had ultimately exerted enough force on it to cause the ejection. Moments before the ejection, the pilot had taken the aircraft into a tight turn, thus causing the G-suit to activate.

For the C and D models of Gripen, the ejection seat handle had been moved and redesigned to make room for larger cockpit displays. The investigation showed that the new handle was prone to these kinds of uncommanded ejections. A survey among the air-wings that fly the Gripen revealed that the ejection handle had become dislodged before, though not far enough to cause an ejection. The investigation concluded that the quality assurance procedures between the Swedish Defense Material Administration, the Swedish Air Force and Saab were not adequate to discover the error in time and were therefore cited as the root cause of the accident.[11]

Hungarian Air Force

May 2015

On 19 May 2015, a two-seater JAS 39 D number 42 from the Hungarian Air Force overran the runway at Čáslav Air Base, Czech Republic. Both crewmen (Bg.Gen Ugrik and Maj. Grof) ejected safely with no injuries. The aircraft was heavily damaged with the nose section separated.[12]

June 2015

On 10 June 2015, a single-seater JAS 39C number 30 from the Hungarian Air Force performed a belly landing at Kecskemét Air Base, Hungary. The pilot, Major Sándor Kádár, ejected successfully, but suffered spinal injuries. The aircraft is under repair.[13][14]

Royal Thai Air Force

January 2017

On 14 January 2017, a Gripen crashed during an air show for the Children's Day in Hat Yai, Songkhla province, Thailand. Sqn Ldr Dilokrit Pattavee was killed when the aircraft crashed on a runway at Wing 56 during the air show at around 9.20 am. About an hour later, Thai media reported an airport fire engine overturned while rushing to put out the fire. Hat Yai International Airport had to close to clear the runway. The cause of the crash is not yet known.[15]

Other incidents

Swedish Air Force

October 2007

On 3 October 2007, a Swedish Air Force Gripen had a separation conflict with a passenger aircraft, i.e. they did not keep the required separation in altitude and distance. The passenger aircraft was a Saab 340 from Avitrans Nordic on its way from Ronneby to Bromma. At their closest, the aircraft were separated 30 meters vertically and 950 meters horizontally. The incident took place in the airspace south of Oskarshamn. The pilot on the passenger aircraft was alerted by the TCAS that another aircraft was approaching at the same altitude.

SHK concluded that the incident took place because the Gripen pilot inadvertently went below his assigned flight level and ended up on the same flight level at the passenger aircraft. SHK placed the root cause of this with the lack of adequate routines in the Swedish Air Force for receiving and reading back instructions from air traffic control. A contributary cause of the incident was said to be a lack of support systems in the Gripen to help the pilot with the aforementioned task. Such a system is currently being introduced in the Swedish Air Force Gripens. The system will alert the pilot if the flight deviates from the assigned flight level.[16]

August 2009

On 6 August 2009, a Gripen from F 17 Kallinge belly-landed and skidded off the runway, after the pilot forgot to extend the landing gear before landing. A minor fire broke out, but it was soon put out by the airbase fire brigade. The pilot escaped unharmed and could walk away from the aircraft. According to the SHK report,[17] a contributory cause was high mental workload because the pilot had recently transitioned to flying JAS 39C, which uses international units (feet, knots) instead of metric units (meters, km/h). The ground proximity warning system activated 8 seconds before touchdown, but the pilot disregarded it because it was known to sometimes give false alarms.

May 2010

On 31 May 2010, a Gripen from F 21 Luleå came loose and speeded away during a static engine test. The aircraft gained considerable speed before rolling off the hard surface and onto nearby soft terrain, where it finally flipped over.[18][19] The technician in the aircraft, lieutenant Sandra Halvarsson, escaped with minor injuries.[20] There is unconfirmed information that the engine was accidentally started with full throttle.[21] As the accident did not involve a plane flying or preparing to fly, it is not considered to be a crash.

Czech Air Force

October 2006

On 11 October 2006, a pilot from the Czech Air Force flying a Gripen almost hit a target-towing Learjet 35 in a live fire exercise at Vidsel airfield in northern Sweden. When practicing using the on-board automatic cannon, the Czech pilots mistakenly targeted a reserve target close to the towing plane instead of the intended target 600 meters behind it. After several "dry runs", live firing commenced, and the first pilot fired on the reserve target. Several rounds hit it, and were calculated to have passed within 10 meters of the Learjet. After this the Czech pilots discovered the actual target they were supposed to fire on, and proceeded to attack it instead. The crew of the Learjet did not notice anything out of the ordinary besides hearing the sound of the cannon, without making the connection that they had been fired upon. The incident was discovered after landing.

SHK's investigation concluded that the causes of the incident were that too many activities were scheduled for too short a time span; that the safety regulations concerning live fire exercises were outdated; and that the assignment of responsibilities and duties of the Swedish Armed Forces, the Swedish Defence Material Administration, Saab Special Flight Operations and the Czech military units were unclear. These causes put together resulted in the Czech pilots not being fully aware of the true configuration of the Learjet and the targets, which in turn led to them targeting the wrong target and one of them eventually firing on it. Contributing causes were that the Czech pilots had little to no experience of this kind of exercise, and that the target-towing Learjet had no means of monitoring the exercise. For instance the Learjet lacked a radar warning receiver that could have revealed that they had been targeted by the Gripens.[22]

Notes

  1. ↑ A woman was hospitalized for three weeks for burns.[6]

References

  1. ↑ "Sveriges Television", You tube (in Swedish), Google.
  2. 1 2 3 4 5 Lindqvist, Gunnar & Widfeldt, Bo, Rikets flygplanköp – JAS 39 Gripen, Nässjö, SE: Air Historic Research, 2003, ISBN 91-973892-5-0, pp. 164–68 (in Swedish).
  3. ↑ https://www.flightglobal.com/FlightPDFArchive/1989/1989%20-%200734.PDF
  4. ↑ http://history.saab.com/teman/svensk-sakerhet/jas-39-gripen/
  5. ↑ "Sveriges Television", You tube (in Swedish), Google.
  6. ↑ Coping with a Credibility Crisis: The Stockholm JAS Fighter Crash of 1993 (PDF), Swedish National Defence College, p. 27, retrieved 23 January 2012.
  7. ↑ Statens haverikommission Archived July 2, 2007, at the Wayback Machine., SHK (Swedish Accident Investigation Board).
  8. ↑ "Rapport RM 2002:02" Archived August 11, 2014, at the Wayback Machine., Swedish Accident Investigation Board (in Swedish).
  9. ↑ "Rapport RM 2007:03" Archived August 18, 2010, at the Wayback Machine., Swedish Accident Investigation Board (in Swedish).
  10. ↑ "Jas aircraft crashed in Norrbotten" Archived March 26, 2009, at the Wayback Machine., Sveriges Television (in Swedish).
  11. ↑ "Rapport RM 2008:01" Archived August 17, 2010, at the Wayback Machine., Swedish Accident Investigation Board (in Swedish).
  12. ↑ Chamonikolas, Krystof; Simon, Zoltan, "Hungarian Gripen Fighter Jet Crash-Lands in Czech Military Drill", Business, Bloomberg, retrieved 19 May 2015, A Hungarian Jas-39 Gripen fighter, made by Saab AB, crash-landed during a military drill in the Czech Republic.
  13. ↑ "Hungary: Pilot stable after crash landing Gripen fighter jet", The Big Story, AP, retrieved 10 June 2015, BUDAPEST, Hungary (AP) — Hungary's defense ministry says a pilot who ejected from his Gripen fighter jet during a crash landing is in stable condition..
  14. ↑ "Örökre búcsút mondhatunk a Gripennek?", Magyar Nemzet Online (in Hungarian), MNO, retrieved 10 June 2015, Portálunk úgy értesült, hogy a pilótának, Kádár Sándor őrnagynak csigolyatörése van és Kecskemétről Budapestre szállítják a Honvédkórházba..
  15. ↑ Gripen jet crashes during air show, pilot killed, Post Publishing PCL., 14 January 2017.
  16. ↑ "Rapport RM 2010:01" Archived August 17, 2010, at the Wayback Machine., Swedish Accident Investigation Board (in Swedish).
  17. ↑ Swedish Accident Investigation Board (2012-11-09). "Olycka den 6 augusti 2009 med en JAS39 nr 39.212 vid Blekinge flygflottilj". Retrieved 2017-06-15. (in Swedish)
  18. ↑ "Jas-plan voltade på F 21 i Luleå" (Jas aircraft flipped over at F21 in Luleå), Göteborgs-Posten, 31 May 2010 (in Swedish).
  19. ↑ "Haveri med JAS 39 Gripenflygplan" (Incident with JAS 39 Gripen aircraft) Archived July 20, 2011, at the Wayback Machine., press statement from F 21 Luleå, 31 May 2010 (in Swedish).
  20. ↑ ”Jag hade änglavakt” (”I had a guardian angel”), interview released by F 21 Luleå, 2 June 2010 (in Swedish).
  21. ↑ "Frågetecken kring skenande Jas-plan" Archived June 12, 2011, at the Wayback Machine. (in Swedish). Sveriges Television, 1 June 2010. (English translation).
  22. ↑ Rapport RM (PDF) (in Swedish) (4), Swedish Accident Investigation Board, 2007, archived from the original (PDF) on 2011-06-12.
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