2018 Ju-Air Junkers Ju 52 crash
| Industry | Aviation |
|---|---|
| Founded | 1982 |
| Headquarters | Switzerland |
| Products | Heritage sightseeing flights using Junkers Ju 52 aircraft |
On 4 August 2018, a Junkers Ju 52 passenger plane operated by Ju-Air tragically crashed near Piz Segnas, Switzerland, while flying from Locarno to Dübendorf. The accident resulted in the loss of all 20 individuals aboard.
This incident marked the first fatal accident for Ju-Air since its inception in 1982. Investigations were conducted by the Swiss Transportation Safety Investigation Board (STSB) alongside the cantonal police of Grisons, acting on behalf of federal and cantonal prosecutors.
The STSB's conclusive report, published in January 2021, attributed the cause to reckless piloting by two seasoned aviators who disregarded established regulations, failed to anticipate turbulent conditions, and consequently lost control of the aircraft. This led to a stall and spin, culminating in impact with the terrain. Additionally, the report highlighted that the aircraft was not airworthy due to underperforming engines and pointed out significant shortcomings in Ju-Air’s safety culture, characterized by repeated breaches of operational rules.
Aircraft
The aircraft involved was a tri-engine Junkers Ju 52/3mg4e, bearing registration HB-HOT and manufacturer serial number 6595. It was in service with the Swiss Air Force from 1939 until 1985 before being operated by the Association of the Friends of the Swiss Air Force (Ju-Air) for heritage sightseeing flights, having accumulated over 10,000 flight hours. Ownership remained with the Swiss Air Force throughout.
HB-HOT featured in several films including Where Eagles Dare (1968), Valkyrie (2008), and the German production Bis zum Horizont, dann links! (2012). It possessed a valid airworthiness certificate issued by the Federal Office of Civil Aviation in April 2018, with validity extending for two years.
Passengers and crew
Onboard were three crew members and seventeen passengers, predominantly Swiss nationals except for an Austrian family comprising a couple and their son. The group included nine females and eleven males. The Junkers was flown by two highly experienced captains aged 62 and 63, both with extensive backgrounds at Swissair, Swiss, Edelweiss airlines, as well as over three decades of service in the Swiss Air Force militia. Each pilot had logged several hundred flight hours on the Ju 52. The third crew member was a flight attendant aged 66 with four decades of professional experience.
Accident
During the return segment of a two-day journey from Locarno Airport to Dübendorf Air Base, the aircraft took off from Runway 26R at Locarno at 16:14 local time under visual flight rules (VFR). Weather conditions were unusually warm with gusty winds. After passing Lake Maggiore and executing a 180-degree turn, it proceeded over the Blenio Valley while steadily ascending.
Following a scenic path, the plane reached a basin southwest of Piz Segnas, climbing to an altitude of 2,833 meters above sea level. The crew made announcements highlighting local landmarks as ground speeds fluctuated between 135 and 200 km/h while altitude decreased.
Approaching the Tschingelhörner peaks en route to the Martinsloch rock window, the pilots sought to provide tourists with close views by flying near this feature. As altitude dropped, propeller revolutions slowed and pitch increased. When initiating a right turn toward Martinsloch, the aircraft banked left unexpectedly; airspeed continued to decline while left bank angle increased. Mild turbulence was followed by a sudden severe left bank. Despite efforts to recover control, airspeed kept decreasing as bank angle deepened to approximately 68 degrees downward and the plane entered an almost inverted dive.
At 16:56 local time (14:56 UTC), the Junkers collided with Piz Segnas mountain at an elevation of 2,540 meters, striking at nearly vertical angle with an estimated speed of around 200 km/h. All twenty occupants lost their lives in this crash.
Immediate aftermath
During the recovery efforts, hiking trails and local airspace were temporarily shut down, with five helicopters deployed to assist. Ju-Air halted all operations of its other Ju 52 planes for a fortnight, resuming flights on 17 August under enhanced safety protocols.
Investigation
The crash was examined collaboratively by the Swiss Transportation Safety Investigation Board (STSB) alongside the cantonal police of Grisons, representing federal and cantonal prosecutors. A spokesperson described the Junkers as having "plummeted like a stone," suggesting the 2018 European heatwave might have impaired its climb capabilities. No emergency transmissions were detected before impact. Investigators excluded collision, sabotage, or component detachment prior to the accident.
Due to the aircraft’s vintage status, it was not equipped with flight recorders; therefore, investigators turned to passenger photographs and videos for supplementary information. On 15 August 2018, the STSB issued an initial report. A subsequent interim report released on 20 November grounded Ju-Air’s remaining Ju-52 fleet after identifying corrosion and structural cracks unrelated to the accident but necessitating further evaluation.
A confidential draft report revealed that the pilots had navigated into a high-altitude alpine valley lacking safe escape routes and had a documented history of hazardous choices, including disregarding minimum altitude requirements during check flights. Mechanical failure was ruled out as a cause.
Cause of stall
It was determined that the crash resulted from an aerodynamic stall triggered by several factors, notably poor crew judgment compounded by hot and high environmental conditions. The decision to follow a scenic flight path near Piz Segnas exposed the aircraft to perilous external elements. This choice highlighted broader deficiencies in safety culture and routine breaches by both crew members and the operator.[1]
To enhance passengers’ views of surrounding terrain, the crew descended in altitude, which reduced their margin for recovery and heightened risk exposure. They also slowed airspeed to approximately 100 knots. The combination of clear skies and elevated terrain decreased air density, adversely affecting aircraft performance. Approaching mountainous terrain, turbulent airflows with alternating updrafts and downdrafts influenced the aircraft’s angle of attack.[1]
A downdraft forced the nose downward, causing loss of altitude. The pilots countered with nose-up control inputs, stabilizing pitch above flight level. However, when the downdraft abruptly ceased and an updraft occurred during a left turn, airspeed dropped dangerously close to stall speed. The left wing stalled due to insufficient speed and aircraft design characteristics, resulting in a severe left bank.[1]
The crew attempted corrective action by initiating a left turn consistent with Ju-Air Junkers’ recovery procedures. Nevertheless, insufficient altitude prevented successful recovery, leading to an uncontrollable stall.[1]
Safety violations
The decision to fly over a basin known for hazards underscored systemic issues within the safety culture. Investigations uncovered persistent reckless conduct by pilots. Pilot A repeatedly breached minimum altitude rules yet received a "standard" rating; Pilot B also operated dangerously low but was rated "high standard."[1]
An analysis of 216 flights between April and August 2018 revealed that over one-third were conducted under high-risk conditions; several were classified as "very high risk." Both involved pilots ranked among the worst offenders, each exhibiting twice the average number of risky flights.[1]
According to EASA regulations, Ju-Air’s Junkers Ju 52 planes were required to maintain at least 2,000 feet above terrain within 9.3 km of their route. However, operational constraints limited flights below 2,500 feet due to potential engine failures at higher altitudes. Additionally, the operator imposed further restrictions on flights below 10,000 feet to minimize passenger discomfort caused by lack of cabin pressurization—despite EASA recommendations suggesting approximately 12,500 feet for safe operations in such terrain.[1]
Contributing factors to this safety neglect included employing Swiss Air Force pilots accustomed to more lenient military standards and inadequate regulatory oversight regarding vintage aircraft operations by local aviation authorities.[1]
Additional shortcomings surfaced: repeated miscalculations of aircraft weight shifted its center of gravity unfavorably, potentially increasing stall risk. Maintenance inspections uncovered extensive corrosion and cracks on the crashed aircraft; no records indicated major overhauls had been performed. Since production of Junkers Ju-52 ceased decades ago, replacement parts had to be custom fabricated.[1]
In March 2019, amid ongoing investigations, Switzerland’s Federal Office of Civil Aviation (FOCA) prohibited Ju-Air from conducting commercial passenger flights using Ju 52s, allowing only private club operations. Subsequently, operating and maintenance certifications for other Swiss-based Ju 52s were revoked due to unsafe maintenance practices identified in HB-HOT’s wreckage investigation; this action grounded sister ships HB-HOP and HB-HOS.[2]
Oversight shortcomings
Although numerous safety breaches were evident, FOCA, the agency tasked with airline supervision, failed to detect managerial deficiencies or mandate remedial measures. FOCA's erroneous classification of the Junkers Ju-52 as a "standard" instead of a "historic" aircraft resulted in inspectors lacking expertise in vintage aviation overlooking significant operational hazards. Issues such as inaccurate basic empty weight calculations impacting the plane's center of gravity were disregarded. Inspectors noted hazardous flights conducted close to terrain but did not escalate these concerns, and the airline’s internal safety management system neglected to mitigate persistent high-risk operations.
FOCA’s inability to identify and address these critical lapses, coupled with its failure to assert regulatory control over the airline’s non-compliance, was recognized as a systemic contributor to the accident.
Summary
The STSB’s conclusive report dated 28 January 2021 determined that "the pilots' engagement in high-risk maneuvers directly caused the accident," emphasizing low-altitude flying without viable alternatives and dangerously reduced airspeed amid turbulent conditions, which led to loss of control. The investigation also found the aircraft was operated beyond its aft center of gravity limit and deemed unairworthy due to poorly maintained engines delivering inadequate thrust. The report underscored a deficient safety culture within the operator that permitted hazardous conduct and breaches of regulations.
See also
External links
- Animated video depicting the accident flight (English, released by Swiss Transportation Safety Investigation Board).
- Articles with short description
- Filmed deaths during aviation accidents and incidents
- Accidents and incidents involving the Junkers Ju 52
- August 2018 in Switzerland
- Aviation accidents and incidents in 2018
- Aviation accidents and incidents in Switzerland
- Aviation accidents and incidents caused by pilot error
- 2018 disasters in Switzerland
- Pages with reference errors