Emergency landing, Diamond DA40 TDI, PH-TDS, Den Bommel
The pilot experienced engine problems, which were followed by a complete engine failure. He made an emergency landing in a crop field, which damaged the aircraft.
In October 2020 the Bundesstelle für Flugunfalluntersuchung (BFU) and the German manufacturer accomplished a further teardown of the engine of PH-TDS. Besides other damage it appeared that stud bolts of one of the crankshaft main bearing caps were broken. At the same time a similar engine from Ethiopia was investigated. Its teardown also revealed a broken stud bolt, however, its crankshaft was still intact. It is suspected that both the stud bolts of PH-TDS and of the engine from Ethiopia failed due to fatigue. In February 2021 the BFU reported to the DSB that – in addition to the occurrence with PH-TDS – four other in-flight engine failures were known.
Corrective actions
On 18 December 2020 the engine manufacturer issued a Service Bulletin (SB) to owners and maintenance organizations. The SB refers to the engine serial numbers of this type of engine which have been equipped with stud bolts from suspected batches. The manufacturer will replace these stud bolts and has determined the limits of flight hours and time within which this replacement has to be carried out. The efforts of the manufacturer are monitored by the oversight authority EASA, which approved the technical information in the SB.
In September 2021 the BFU reported that 370 engines had been returned to its production facility for inspection. This major safety action of the manufacturer resulted into the discovery of another 17 engines (22 in total when including the in-flight failure cases) with failed stud bolts.
More about this incident can be found in the Quarterly Aviation Report Q3 2021.
