Date:	Friday 30 July 2021
Time:	15:30 LT
Type:	AgustaWestland AW189
Owner/operator:	Bristow Helicopters
Registration:	G-MCGT
MSN:	92006
Fatalities:	Fatalities: 0 / Occupants: 4
Other fatalities:	0
Aircraft damage:	None
Category:	Incident
Location:	Near Heads of Ayr, South Ayrshire -   United Kingdom
Phase:	En route
Nature:	Training
Departure airport:	Glasgow-Prestwick Airport (PIK/EGPK)
Destination airport:
Investigating agency:	AAIB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
During a pre-fight brief for a SAR training flight, the co-pilot highlighted an event on a previous flight which had resulted in unexpected pitch oscillations following the selection of the Transition Down mode of the Automatic Flight Control System (AFCS). On the conclusion of the other training priorities for the flight, the crew replicated the circumstances that had triggered the pitch oscillations previously; this resulted in similar unexpected flight path oscillations in the pitch axis. The crew reported this second event to the operator.

The event was caused by a shortcoming in the design of the Phase 5 version of the AFCS software SAR upper modes which also resulted in incorrect AFCS mode indications to the flight crew. To address this issue pending the correction of the AFCS software in the Phase 9 release, the helicopter manufacturer issued a Technical Information Letter detailing actions to be taken in the event of a re-occurrence and updated the FMS Pilot’s Guide for Phase 5, Phase 6 and Phase 8 software. The manufacturer has corrected the design shortcoming in the Phase 9 release of the AFCS software.

Safety action has been implemented by the operator regarding automation management and incident reporting.

1. AAIB Final Report: https://assets.publishing.service.gov.uk/media/6329baa1e90e073725585d4d/Leonardo_AW189_G-MCGT_11-22.pdf
2. https://www.helis.com/database/cn/41441/
3. https://www.planelogger.com/Aircraft/Registration/G-MCGT/897061
4. https://en.wikipedia.org/wiki/Heads_of_Ayr

Other occurrences involving this aircraft


26 July 2021

G-MCGT

Bristow Helicopters

0

Ballintoy Harbour, County Antrim, Northern Ireland

non

The AAIB has published a report into a Leonardo AW189 (G-MCGT) experiencing unexpected pitch oscillations near Heads of Ayr on 30 July 2021.

Read the report https://t.co/acElAhrXJ2#AviationSafety pic.twitter.com/j2GpNyC4f5

— AAIB (@aaibgovuk) September 29, 2022

AgustaWestland AW189 G-MCGT at Glasgow/Prestwick 20.6.2017

Date/time	Contributor	Updates
30-Sep-2022 14:35	Dr. John Smith	Added
30-Sep-2022 14:36	Dr. John Smith	Updated [Departure airport, Embed code, ]
16-Feb-2024 12:55	ASN	Updated [Accident report, ]
25-Feb-2024 09:04	ASN	Updated