Swiss Investigation of Piper PA-28-181 Archer II Incident at Grünenmatt (HB-PPV)

Incident Overview and Aircraft Details On 6 February 2012, a Piper PA-28-181 Archer II with registration HB-PPV was involved in a serious incident during a visual flight rules (VFR) training flight. The aircraft, owned and operated by the Segel- und Motorfluggruppe Grenchen, made an emergency landing in the Gemeinde Grünenmatt/BE at 13:27 local time. The flight phase was identified as an emergency landing exercise, and the incident type was recorded as engine failure with emergency landing. The location was Waldhaus, Gemeinde Grünenmatt/BE, at coordinates 621 460 / 206 700 and an elevation of 652 m/M. ## Personnel and Operational Context The pilot was a Swiss citizen born in 1947, holding an airline transport pilot licence (ATPL(A)) and a flight instructor rating for airplanes. He had a total of 18,128 flight hours, including more than 2,000 hours on the accident type. The student pilot had no licence and 22:15 total flight hours, all on the accident type. The flight was a private VFR training flight conducted by Swiss Aviation Training (SAT), which used the infrastructure and aircraft of Flugschule Grenchen (FSG) for its visual flight rules basic training. ## Background and Pre-Flight Conditions The incident occurred during a training flight for SAT, which offered integrated transport pilot training courses. In the winter of 2012, operations in Grenchen were frequently disrupted by high fog, causing the training schedule to fall behind. On 4 February 2012, training was suspended due to temperatures around -10 °C and the lack of engine preheating units. On the morning of 6 February 2012, the SAT VFR training manager instructed the course leader not to take risks despite the schedule delay. A briefing was held with flight instructors, covering the upcoming program, which included emergency landing exercises in the terrain. ## Pre-Heating and Engine Start Accounts of the pre-heating and initial start of HB-PPV on 6 February 2012 varied. The student and flight instructor stated that the aircraft was pulled out of the hangar for pre-heating, but had to be moved because it was in the way of another aircraft, and an FSG flight instructor started the engine without pre-heating. No one observed pre-heating in the hangar. The FSG manager and SAT course leader disputed this, stating the aircraft was pre-heated for several minutes along with three to five other aircraft using the same units in the hangar. It was agreed that the engine of HB-PPV could only be started with difficulty and after several attempts by an FSG flight instructor. ## Flight Sequence and Emergency Landing The student was to relieve the FSG flight instructor in the cockpit during warm-up. When the throttle was moved to idle, the engine stopped immediately. After the flight instructor restarted the engine, the student monitored the warm-up. The flight instructor instructed the student to select 1400 RPM for warm-up and never let the RPM fall below 1000. The flight instructor then took the aircraft HB-PPV with two other students, without shutting down the engine. Three flights were conducted on the morning of 6 February 2012. The first flight was from Regionalflughafen Grenchen (LSZG) to Flugplatz Neuchâtel (LSGN), lasting 1 hour and 13 minutes, with no emergency landing exercises. The second flight was a local flight from Neuchâtel, lasting 12 minutes, with the engine not shut down between flights. The third flight returned from Neuchâtel to Grenchen.