Report on aircraft accident near Holmestrand, Norway 22 August 2017 with Aviat Aircraft Inc. S-2B, LN-PTS

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Description

On 22 August 2017 the commander and a passenger flew from Sandefjord airport Torp, Norway (ENTO) to the Holmestrand area with Pitts S-2B, LN-PTS. There are coincidental information from witness testimonials and radar data. From an altitude of approximately 1 600 ft (AGL), the airplane was flown into a maneuver which resulted in a sudden change in the airplane’s position by making a transition from horizontal flight to an approximate vertical rise up to approximately 2 900 ft (AGL) above ground. The maneuver was thus, by definition, aerobatic flying.

At the top of the vertical increase with full engine power, the flight speed decreased until the airplane stood still in the air. The plane then fell back and entered a left backspin. Until control of the airplane was lost, the maneuver appeared as if it was intended to perform a stall turn/hammerhead maneuver. Witness statements and video recording indicate that there was no sign of the commander being close to regaining control of the airplane from the backspin. The airplane collided with the ground and both on board died.

AIBN issues one safety recommendation in connection with this investigation.

The commander had recently conducted self-familiarization on LN-PTS. He had limited experience with the airplane model. The commander had neither sufficient nor required rating to perform aerobatic flying. The Accident Investigation Board Norway (AIBN) considers that the commander in particular had insufficient skills to master a hammerhead/stall turn, which in addition resulted as an inverted spin, in which visual orientation is challenging.

The AIBN considers that the simplification in EASA and the national regulations is positive, but may also be negative for aviation safety. A change to a performance-based regulatory framework requires an adaptation for the involved parties and they must be aware of what the changes entail. The AIBN issues a safety recommendation in report SL RAP 2018/14 (Hamar 19 September 2017, Van’s RV-4, LN-ABF) concerning this.

The AIBN considers that the Civil Aviation Authority Norway should provide appropriate “Safety promotion” information. From an airworthiness point of view, measures should be taken to make probability assessments of new values in connection with weighing. Furthermore, information should be provided on the importance of flight operation personnel complying with the limitations announced in the aircraft’s manuals. A safety recommendation is issued in this connection. In this case, the airplane’s empty weight and corresponding center of gravity values were not used to make mass and balance calculations. Several studies suggest that general pilots have a relaxed attitude towards these limitations.

Safety recommendation

Safety recommendation SL No 2018/15T

22 August 2017, LN-PTS crashed near Holmestrand. In connection with weighing of aircrafts, it exists a requirement of a new weighing if the empty mass has been changed more than +/- 0,5 % of maximum landing mass and/or CG has been changed more than +/- 0,5 % of MAC. Furthermore, it is normally a requirement to do an assessment of the new values with the values from previous weighing. The Accident Investigation Board Norway (AIBN) consider that a form for empty weight and balance should consist of an assessment of the new values with the values from previous weighing. In this case, the airplane’s empty weight and corresponding center of gravity values were not used to make mass and balance calculations. Several studies suggest that general pilots have a relaxed attitude towards these limitations.

The Accident Investigation Board Norway (AIBN) recommends that the Civil Aviation Authority Norway should provide appropriate “Safety promotion” information. From an airworthiness point of view, measures should be taken to make probability assessments of new values in connection with weighing. Furthermore, information should be provided on the importance of flight operation personnel complying with the limitations announced in the aircraft’s manuals.

Location
Holmestrand, Vestfold, Norway
Occurrence date
22.08.2017
Aircraft
Øvrige motorfly
Operator
Private
Registration
LN-PTS
Meteorological conditions
VMC
County
Vestfold
Type of occurrence
Accident
Type of operation
Private
Category of operation
Light, aeroplane (< 5 700kg)
Aircraft category
Landplane, Single-engine, Piston engine
FIR/AOR
ENOS (Oslo ATCC)
Skriv ut
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