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ASN Wikibase Occurrence # 149156
Last updated: 21 July 2020
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Date:15-SEP-2012
Time:19:10
Type:Silhouette image of generic L39 model; specific model in this crash may look slightly different
Aero L-39C Albatros
Owner/operator:Breitling Jet Team
Registration: ES-YLS
C/n / msn: 533638
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Near Valkenswaard -   Netherlands
Phase: En route
Nature:Ferry/positioning
Departure airport:Den Helder-De Kooy (EHKD)
Destination airport:Kleine Brogel AB (EBBL)
Investigating agency: Dutch Safety Board
Narrative:
An Aero L-39C Albatros jet of the Breitling Jet Team (ES-YLS #2) crashed in a field near Valkenswaard, the Netherlands after both pilots had ejected following engine problems.

The Breitling Jet Team formation was flying to Kleine Brogel AB, Belgium after participating at the Heldair Air show at Den Helder, the Netherlands. The team was due to perform a display at the Sanicole Air Show the next day.

The crew of ES-YLS, consisting of the pilot, seated in the front of the aircraft and the mechanic, seated in the rear, both felt engine vibrations, which became increasingly powerful. After a few seconds, the crew smelled a burning odour. Approximately 20 seconds later, the pilot received a general fault warning. The warning light indicating that the engine vibrations were exceeding the safety threshold engaged, and oil pressure started to drop. The pilot notified the other members of the formation that he was experiencing engine problems. Soon after, he heard an explosion after which engine power started to drop. After having received a notification from one of the other formation pilots that flames were coming out of the aircraft's exhaust, the pilot shut off the fuel supply after which the engine switched off. The pilot then activated the fire extinguisher in order to extinguish any potential engine fires. In view of the fact that the aircraft was now too far from Kleine Brogel air base and there was no other airport in the vicinity, the pilot decided that he and the mechanic would have to evacuate using the ejection seats. He then steered the aircraft to a vacant area. At an altitude of approximately 1,500 feet, the mechanic then ejected from the aircraft followed by the pilot. The aircraft crashed in a potato field and was entirely destroyed. The two occupants landed on the ground near the crashed aircraft.

The accident was the result of an engine malfunction caused by a failure of the low pressure turbine front bearing. The bearing failure was probably caused by hydraulic fluid entering the engine oil system or abnormal fouling of the engine oil caused by deposits.

For engine maintenance procedures the qualitative assessment of the particles in the engine oil, as described in the engine maintenance manual, did not take place. Such an additional assessment should have given a better picture of the oil status.

The oil status was especially assessed on the status of the magnetic plug of the overheat and chip detector and on quantitative parameters for particles, for which no written procedures and references existed in the laboratory that performed the analyses, nor with the operator. As such, the outcome of the analyses could not be valued for this engine. The classification of the fluid status was only based on the fact that the oil must be clear.

The aviation company took measures, as advised by the laboratory and continued the flight operation with ES-YLS. The Dutch Safety Board is of the opinion that the operator did not take full opportunity to establish that a normal engine operation was guaranteed. This Aero Vodochody L-39C does not have to comply with European safety level requirements for civil aviation aircraft. As a consequence different standards and practises for maintenance and airworthiness may be applied. This is undesirable according to the Dutch Safety Board.

The lack of adequate oversight in combination with the lack of airworthiness requirements similar to those applied to civil aviation aircraft, may result in potentially unsafe operations .

Sources:

http://www.omroepbrabant.nl/?news/1805961183/Straaljet+neergestort+in+weiland+Valkenswaard.aspx
https://onderzoeksraad.nl:443/en/onderzoek/1921/crash-following-engine-failure-aero-l-39c-albatros-15-september-2012

Accident investigation:
cover
  
Investigating agency: Dutch Safety Board
Status: Investigation completed
Duration:
Download report: Final report


Images:

Photo of ES-YLS courtesy AirHistory.net


Den Helder - De Kooy (EHKD / DHR)
15 September 2012; (c) Bart Hoekstra

Revision history:

Date/timeContributorUpdates
15-Sep-2012 12:51 harro Added
15-Sep-2012 12:54 harro Updated [Cn, Departure airport, Destination airport, Narrative]
15-Sep-2012 13:00 harro Updated [Narrative]
15-Sep-2012 13:01 harro Updated [Embed code]
15-Sep-2012 13:20 RobertMB Updated [Time, Aircraft type, Registration, Cn, Location, Source, Embed code, Narrative]
25-Mar-2016 15:57 harro Updated [Time, Source, Narrative]
25-Mar-2016 15:57 harro Updated [Embed code]
28-Mar-2016 07:54 Aerossurance Updated [Narrative]
01-Jun-2018 08:59 harro Updated [Narrative]

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