CAPT:
Chip detectors are not disabled in ALL turbo-props, only some models-early Dash-8s as example.
I guess the logic behind disabling chip detectors in flight is that pilots won’t be distracted by nuisance chip lights.
The Pilatus PC-12, when first certified in Canada was certified with the engine chip detectors disabled in flight. After an accident at Clarencville Newfoundland in 1998- attributed to engine failure- Transport Canada mandated that they chip detectors be enabled in flight in all single engine aircraft engaged in “commercial”single engine IFR operations.
Here’s an excerpt from the 1998 Transportation Safety Board (TSB) report.
“ The design feature of the chip detector installed on this aircraft was such that indications to the cockpit were disabled whenever the landing gear was retracted; therefore, this installation did not meet the requirements of the standard governing the transport of passengers in single-engined aircraft, Commercial Air Service Standard (CASS) 723.22”
Full report here:
http://www.tsb.gc.ca/en/reports/air/...7/a98a0067.asp