What happened
On September 6, 2016, a Piper PA 34 Seneca II, registration D-GLLW, was conducting a flight from Treviso, Italy, to Skopje, North Macedonia. The aircraft was operating under Instrument Flight Rules (IFR) in complex meteorological conditions characterized by low visibility and moderate to heavy rainfall.
As the aircraft was established on the ILS approach for runway 34 at Skopje Airport, it was being vectored by air traffic control. Following a routine procedure to reduce altitude, the aircraft was transferred to the authority of the tower controller. Immediately after this transfer of jurisdiction, radio and radar contact with the aircraft was lost.
Search and rescue operations were initiated following the loss of signal. Debris from the aircraft was subsequently located across a 2.5-hectare area on the slopes near the village of Kozhle, approximately 14.5 km south of the Skopje Airport runway threshold. The impact analysis indicated that the aircraft underwent structural disintegration while still in flight. There were 6 fatalities in total, including the pilot and five passengers.
The investigation
The investigation examined the flight history, maintenance records, meteorological data, and radar observations. Investigators analyzed the aircraft's previous service history, noting a significant incident in August 2010 involving structural damage. Radar data from the period of the crash was reviewed, though limited by orographic obstacles. Meteorological reports (METAR) confirmed that the flight occurred in Instrument Meteorological Conditions (IMC) with heavy precipitation. The investigation also assessed the aircraft's weight and balance, finding that the takeoff mass significantly exceeded the maximum allowable limits.
Findings
- The aircraft entered an uncontrolled stall during the established instrument approach.
- This stall led to an uncontrolled spiral flight path and subsequent in-flight structural disintegration.
- The aircraft was operating above its maximum allowable takeoff weight.
- The aircraft had completed 670 flight hours since a 2010 incident involving structural damage, without specific inspections of those previous repairs.
- Complex weather conditions, including heavy rain and low visibility, increased the crew's workload.
- The aircraft's Emergency Locator Transmitter (ELT) failed to broadcast a signal.
Safety action
- Following severe incidents involving structural damage, periodic inspections of such repairs should be mandated.
- Strict adherence to maximum weight limits must be enforced during flight operations.
- The Civil Aviation Agency should conduct regular training and capability exercises for units involved in Search and Rescue (SAR) operations and invest in advanced SAR equipment.