Serious incident Airbus A320-232 9H-LOZ, 28 May 2021
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ASN Wikibase Occurrence # 279139
 
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Date:28-MAY-2021
Time:08:25 UTC
Type:Silhouette image of generic A320 model; specific model in this crash may look slightly different    
Airbus A320-232
Owner/operator:Lauda Europe
Registration: 9H-LOZ
MSN: 2838
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:near London-Stansted Airport, Stansted, Essex -   United Kingdom
Phase: Approach
Nature:Test
Departure airport:London-Stansted Airport (STN/EGSS)
Destination airport:London-Stansted Airport (STN/EGSS)
Investigating agency: AAIB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The aircraft was scheduled to conduct a preservation flight, departing from and returning to Stansted Airport and lasting approximately 45 minutes. These were routine flights conducted every 28 days to maintain serviceability of the aircraft during the Covid-19 pandemic reduced flight schedules.

During the final approach to runway 22, at 950 ft radio altitude and with autothrust engaged, an ‘eng 2 fadec fault’ appeared on the Electronic Centralised Aircraft Monitor (ECAM). The crew elected to go around and manually flew the standard missed approach profile, before entering a hold to perform troubleshooting of the fault. During this period the No 2 engine remained at idle despite manual throttle increases and the reselection of autothrust. The crew also reported seeing apparently erroneous engine parameter readings relative to the selected throttle position. After entering the hold, the immediate ECAM checklist actions were performed. The crew reported that the engine indications were not showing amber XX, but appeared to be frozen and were still not responding to any throttle inputs. The ECAM checklist directed that in the case of abnormal engine parameters the engine should be shut down. The crew consulted the Flight Crew Operating Manual (FCOM) for further guidance, before starting the Auxiliary Power Unit (APU) and shutting down the No 2 engine.

The crew declared a MAYDAY and selected squawk 7700. They then briefed for a return to Runway 22 at Stansted. After completing all the necessary single-engine operation checklists and landing performance calculations, they requested radar vectors for a normal ILS approach to Runway 22. Following an uneventful approach and landing, the aircraft vacated the runway and the crew confirmed with the Airport Fire and Rescue Service Commander that the failed engine appeared normal. During the landing rollout as the aircraft airspeed dropped below 70 kts an ‘eng 2 ovspd prot fault’ warning was triggered but this was not displayed on the ECAM. The aircraft was then taxied to Maintenance Hangar 10 at Stansted and shut down in accordance with the relevant checklists.

The manufacturer’s assessment of the failure messages seen on the post-flight report and the ECAM warning was that they were consistent with the reduction in EPR caused by an uncommanded activation of the overspeed protection valve in the FMU. This reduced the fuel flow to the engine to a fixed level which was just below flight idle. The flight data values recorded for N1 and N2 immediately prior to this were normal and confirmed that no actual overspeed had occurred, which would have resulted in the valve correctly operating.
Once activated, the fixed flow rate through the overspeed protection valve cannot be varied by any input from the throttle or the FMGC. As such, the apparently frozen parameters reported by the flight crew were an accurate indication of the engine status.

The other ancillary engine indications and associated systems’ operating parameters recorded by the DFDR were all consistent with this. The valve remained hydraulically latched while the engine was operating but would have reset after the engine was shut down. The final overspeed protection fault warning seen on the post-flight report is intentionally inhibited by the system until after touchdown and the aircraft airspeed has reduced below 80 kt, which is why it appeared to occur after the engine had been shut down. The previous in-service events where the overspeed protection valve had operated without being commanded by the EEC, were very similar to this incident involving 9H-LOZ.

It was not possible to confirm a definitive root cause for the activation of the overspeed protection valve from the evidence recovered by the investigation. However, these events are all the subject of ongoing continued airworthiness activities by the engine and aircraft manufacturers.

Sources:

1. AAIB Final Report: https://www.gov.uk/aaib-reports/aaib-investigation-to-airbus-a320-232-9h-loz
2. https://avherald.com/h?article=4eefa42d&opt=0
3. https://www.aeroinside.com/16266/lauda-europe-a320-at-london-on-may-28th-2021-abnormal-engine-behaviour
4. https://planefinder.net/data/aircraft/9H-LOZ



Accident investigation:
cover
  
Investigating agency: AAIB
Status: Investigation completed
Duration:
Download report: Final report
Other occurrences involving this aircraft

27 Feb 2022 9H-LOZ Ryanair, opb Lauda Europe 0 Wien-Schwechat International Airport (VIE/LOWW) min

Location

Media:

Lauda Europe Airbus A320-232 OE-LOZ at Vienna Airport, Vienna, Austria 1 March 2020: Vienna-Airport 3045

Revision history:

Date/timeContributorUpdates
09-Jun-2022 11:16 harro Added
09-Jun-2022 11:17 harro Updated [Operator]
10-Jun-2022 18:58 Dr. John Smith Updated [Location, Source, Embed code, Narrative, Category]

Corrections or additions? ... Edit this accident description

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