MH60T Trivia #226-250
This trivia series distills over 20 years of flight manual study into 500+ focused questions and answers, posted in 25 question sets. It’s not a substitute for the manual, but rather an aid to facilitate study and strengthen airmanship. During your review, ask yourself: How is this operationally relevant? Do I need to memorize it, or just be familiar with it? Should I review more on this topic?
226. Q: ESU shutdown parameters?
A: ESU monitors APU temp and speed combos. It can display 13 reasons for shutdown.
227. Q: APU is shut down automatically by the ESU for abnormalities except for what condition?
A: Oil temp high (caution light only).
228. Q: Pressure that results in the APU ACCUM LOW advisory?
A: 2650 psi (APU can start with lower pressure – I’ve seen a successful start at 1800 psi – but it is not a sure thing).
229. Q: The DECU provides what?
A: TGT limiting, load/torque sharing, sensing (cockpit indication) for torque, Np, and TGT, Np governing, Np overspeed protection, hot start preventer, TGT bias and auto start.
230. Q: What are the additional functions added with the EDECU?
A: EDECU adds – transient droop response, auto relight (Np less than 120 with Ng reaching a programed deceleration rate), and auto contingency power
Notes on auto contingency power – As of 9/25 there are a mix of P07 and P08 EDECUs in the CG H60 fleet. The P07 EDECUs activate auto contingency power when the opposite engine is producing less than 50% Q. The P08 EDECUs activate auto contingency power is when Np drops below 96%, greater than 3% droop between actual Np speed and Np reference speed, or a greater than 5% per second Np droop rate when actual Np is less than or equal to Np reference speed. There is no advisory for auto contingency power.
231. Q: HMU provides what?
A: Ng overspeed, collective compensation, stall and flameout protection.
232. Q: DECU lockout deactivates what eng. control systems?
A: TGT limiting, Np governing, load sharing.
233. Q: Does lockout deactivate Np overspeed protection?
A: No.
234. Q: Ng overspeed protection secures fuel flow at what %?
A: 110% +/-2% Ng.
235. Q: Np overspeed secures fuel flow at what %?
A: 120% +/-1 % Np.
236. Q: What Np/Nr is required to test the overspeed system?
A: Greater than 96% (in test it resets the overspeed limit from 120% to 96%).
237. Q: If both Test A and B are pressed, what does the ignitor do?
A: Comes on for 5 seconds to relight engine.
238. Q: The Engine Alternator has three separate windings that power what:
A: DECU, ignitor assembly, Ng signal to EICAS.
239. Q: Indications of a failure of the Ng winding in the alternator?
A: Loss of Ng display on the EICAS page, a red “X” on the engine display for the affected engine and the respective engine out Master Warning light illuminated.
240. Q: The DECU receives what inputs from the pilot?
A: Np reference trim and contingency power (also lockout).
241. Q: Np beeper trim operates over what range?
A: 96% to 101%.
242. Q: Eng. trim malfunction notes:
A: Expect the low rotor annunciation and caution (do not fly a helicopter with all green EICAS indications into the water because of an engine trim malfunction – I’ve seen this occur in the sim several times), reset trim, and pull c/b if necessary.
243. Q: Normal TGT limiting is set to what temp?
A: 862-876° – EDECU (no greater than 878°).
244. Q: Cont. power increases the TGT limiting to what temp.?
A: 886 – 901°.
245. Q: What are the limits that will cause the DECU hot start preventer to cut fuel flow during a hot start?
A: TGT greater than 900, Ng less than 60%, Np less than 50%.
246. Q: If the DECU cuts fuel to prevent a hot start, when is fuel flow restarted?
A: TGT less than 300, or after 25 sec., whichever occurs first.
247. Q: How do you bypass the hot start preventer?
A: Press and hold either test A or B for the start.
248. Q: DECU fault codes are displayed where?
A: On the AC status page and on the torque meter (need AC power).
249. Q: How are DECU fault codes suppressed/recalled?
A: Codes can be suppressed/recalled by pressing either overspeed test button.
250. Q: How are DECU fault codes cleared?
A: To clear codes, engines must be run at idle.