CAA NZ Basic Turbine Knowledge (Helicopter) Exam case studies
CAA NZ Basic Turbine Knowledge (Helicopter) Exam · Put your knowledge to work in context.
The CAA NZ Basic Turbine Knowledge (Helicopter) examination is a multiple-choice theory assessment for people working towards a New Zealand aircraft maintenance engineer licence with a helicopter turbine rating. It tests the foundational knowledge a licensed engineer needs before certifying maintenance on turbine-powered helicopters: how a gas turbine produces power, how its modules are built and cooled, how fuel, oil, ignition and control systems work, and how that power is delivered through the main rotor drive, tail rotor drive and freewheeling unit. The CAA NZ Basic Turbine Knowledge (Helicopter) Exam case studies are 5 cases and about 3,435 words.
1Compressor fouling, a wash, and a surge on the post-wash run
A Bell 206B-3 powered by an Allison 250-C20J has been working for 150 hours from a coastal airfield and nearby sandy agricultural strips. At maximum continuous torque the pilot has watched Ng climb from 93.8% to 96.2% and TOT from 710 °C to 758 °C; fuel flow at the same torque is about 8 lb/h higher than the earlier baseline.
735 words, about 4 min2Dragging sprag clutch detected during an autorotation
An Airbus H125 (AS350 B3) is used for charter. During a practice autorotation at 3,000 ft AGL and 65 KIAS, the pilot lowers collective.
712 words, about 4 min3Hot start on a cold morning with a weak battery
A Bell 206B-3 (Allison 250-C20J) is to be started on a -2 °C morning. The battery is 4 years old and shows 22.5 V before start; the manual requires a minimum of 24 V for a battery start.
671 words, about 3 min4Chip detector fuzz with an oil pressure fluctuation
After a 1.5-hour flight, the pilot of a Bell 206B reports that engine oil pressure fluctuated between 45 and 60 psi during a 10-minute climb, then returned to normal. Oil temperature peaked at 98 °C; the limit is 107 °C.
682 words, about 3 min5Boost pump failure and suction feed at altitude
An AS350 B2 with an Arriel 1D1 is on a scenic flight at 9,500 ft, OAT +18 °C. The fuel boost pump caution light illuminates.
635 words, about 3 min