Probe can’t pinpoint crash cause
‘‘Ultimately our deepest concern at this point is that this doesn’t happen again to others. We continue to mourn the loss of Eric and Kathy and miss them deeply. We remain proud of their accomplishments and the example they set in their lives.’’ Hertz and Picone families
The aircraft in which 2degrees boss Eric Hertz and his wife Kathy died ‘‘departed controlled flight’’ and went into an unrecoverable spin before crashing into the sea, the Civil Aviation Authority says.
Hertz, 58, and wife Katherine Picone Hertz, 64, died when their twin-engined Beechcraft crashed in the sea south of Gannet Island off the Raglan coast on March 30, 2013.
The authority said the investigation was one of the most complex aviation safety probes of recent times.
Investigators could not find a single cause but were able to identify a series of contributing factors.
The investigators decided on a number of technical safety recommendations relating to a turbocharger induction inlet duct regarding manufacturing and production inconsistencies.
In a joint statement from the Hertz and Picone families, they said they appreciated the work involved in the accident investigation but that there were still no answers.
They questioned why an aircraft was cleared to fly with what was now known to be a problem with a turbocharger.
‘‘Despite these efforts it is disappointing that we still do not know conclusively why engine failure occurred.
‘‘There are no answers yet as to why an aircraft that had recently experienced a similar engine failure on the very same engine, when fitted with an after-market turbocharger system with significant manufacturing inconsistencies, was then cleared to fly with a known insecure part on one engine.
‘‘The answers to these questions reach beyond our families, benefiting other owners of Beechcraft Baron aircraft worldwide that either have been modified with this type of turbocharger system or are considering it.
‘‘Ultimately our deepest concern at this point is that this doesn’t happen again to others.
‘‘We continue to mourn the loss of Eric and Kathy and miss them deeply. We remain proud of their accomplishments and the example they set in their lives.’’
Findings concluded that the pilot experienced a reduction in power, or a power loss, from the left engine during the afternoon flight on the Easter long weekend.
Hertz also failed to disclose a diagnosis of anxiety disorder, or major depressive disorder, which would likely have prevented his securing a medical certificate.
The CAA said the investigation was not suggesting this failure to disclose a medical condition was the cause of the crash.
Without a medical certificate, though, he would not have been allowed to fly in New Zealand.
There was also limited oversight of privately-operated, foreign-registered aircraft permanently based in New Zealand, the report said.
Wreckage was submerged on the sea floor 56 metres below the surface.
Hertz was the pilot when the aircraft departed controlled flight and entered a spin.
Association lead investigator and report author Dan Foley said the investigation was extraordinarily complex from day one.
‘‘This was one of the most extensive and high-profile aviation safety investigations undertaken by CAA in recent years.
‘‘It involved more than 2000 hours’ work with the CAA’S three most senior safety investigators.’’
The probe was unable to conclude the exact cause of the spin.
‘‘The CAA could not conclusively establish what caused the aircraft’s airspeed to decrease to the point from which the departure from controlled flight occurred.
‘‘However, it is considered most likely that the pilot experienced a reduction in power or power loss from the aircraft’s left engine.’’
The turbocharger’s manufacturing testing regime may not fully replicate the actual operating environment, according to the CAA.
Hertz was an American with New Zealand residency and the chief executive of the mobile phone company.
His wife was active in Maori and Pacific education at the Auckland University of Technology.
A recovery operation involved the Raglan coastguard, police and navy divers and the specialist dive vessel, with a 4-strong crew for 10 days. Experts from the United States were called in to contribute to the investigation.
The regime for registering foreign-registered aircraft in New Zealand will also be reviewed.