Date:	Thursday 5 April 2018
Time:	11:40 LT
Type:	Eurocopter EC 135P2+
Owner/operator:	National Police Air Service (NPAS)
Registration:	G-POLA
MSN:	0877
Year of manufacture:	2010
Engine model:	Pratt & Whitney Canada PW206B2
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	None
Category:	Serious incident
Location:	Morpeth, Northumberland -   United Kingdom
Phase:	Manoeuvring (airshow, firefighting, ag.ops.)
Nature:	Test
Departure airport:	Newcastle Airport (NCL/EGNT)
Destination airport:	Newcastle Airport (NCL/EGNT)
Investigating agency:	AAIB
Confidence Rating:	Information verified through data from accident investigation authorities

Narrative:
AAIB investigation to EC135 P2+, G-POLA: Loss of NR control during flight test due to a faulty N2 adjuster, Morpeth, Northumberland, 5 April 2018. The incident was investigated by the AAIB as a "serious incident", and the following is the summary from the AAIB Report

"During a maintenance flight to adjust engine speed, main rotor rpm varied between its maximum and minimum continuous limits. A mechanical stop within the adjusting potentiometer had failed in such a way that main rotor speed could not be controlled accurately, putting the helicopter at a significant risk. The pilot had not been specially trained to carry out the flight test but his actions in flight prevented rotor speed exceeding its limits and a more serious outcome. The manufacturer and operator have taken safety action regarding the conduct of airborne engine speed adjustments."

=Damage Sustained to airframe=
Per the above AAIB Report the damage sustained was "None". The helicopter was checked over, and returned to service.

1. AAIB Report: https://assets.publishing.service.gov.uk/media/5f5a315d8fa8f51061921ebf/EC135_P2__G-POLA_12-19.pdf
2. http://aerossurance.com/helicopters/ec135p2-nr-control-loss/
3. https://www.helis.com/database/cn/26298/
4. https://www.airport-data.com/aircraft/G-POLA.html
5. https://www.planelogger.com/Aircraft/Registration/G-POLA/
6. https://en.wikipedia.org/wiki/Morpeth,_Northumberland

This Eurocopter EC 135P2+ was built in 2010, and was first registered (from new) on 11 February 2010 as G-POLA to the manufacturers (Euocopter UK Ltd) for test flying and delivery purposes. The first operational owner was the West Midlands Police Authority from 2 September 2010. On 15 October 2013, the ownership was transferred to the National Police Air Service, with the helicopter being operated from Wakefield by West Yorkshire Police. There was a nominal change of ownership on 19 May 2021, with the registered owner changing from "Police and Crime Commissioner for West Yorkshire" to "West Yorkshire Combined Authority" (although retaining the same registered address).

Following the incident at Morpeth on 5 April 2018, the helicopter was checked over and returned to service. As at 7 July 2022, G-POLA had accumulated a total of 11,856 flying hours on the airframe

Eurocopter EC135 serious incident, Northumberland https://t.co/q4SzTMIdbu pic.twitter.com/DUINvzF5SF

— AAIB (@aaibgovuk) October 24, 2019

#OTD in 2018 A loss of control of N2, and therefore of NR, was caused by the absence of the stop ring mechanism within this EC135P2's N2 adjuster.https://t.co/8FDzSZAV3r #helicopter #flightsafety #aviationsafety pic.twitter.com/hozbPJPlQF

— Aerossurance (@Aerossurance) April 5, 2021

Date/time	Contributor	Updates
24-Oct-2019 18:49	Aerossurance	Added
13-Dec-2019 20:20	harro	Updated [Embed code, Accident report, ]
05-Apr-2021 09:35	Aerossurance	Updated [Departure airport, Destination airport, Embed code]
04-Jul-2024 06:18	Dr. John Smith	Updated [Source, Embed code, Narrative, Category]