Fam 7 Discuss Items

=Transmission System= Warning: Since the freewheeling unit is mounted at the power output gear, the two oil systems are only separated by oil seals. A failure of a seal will allow transmission oil to enter the engine oil system and cause an  overfull condition. The only indication of a seal failure will be the overfull reading on the dipstick.

Description
The transmission is located forward of the engine on the cabin roof deck and is linked to the freewheeling unit coupling by means of a barbell-shaped driveshaft. The transmission is placed approximately at the midpoint of the center-of-gravity travel and is attached to the airframe by two pylon support links. A dual focal mount aligns the transmission and isolates vibrations. A spike is mounted beneath the transmission; rivets secure the spike-well plate to the transmission deck. Indications of rubbing, sheared rivets, or a loose spike-well plate provide a means of indicating damage resulting from excessive transmission movement. The two-stage planetary transmission system provides a gear reduction of 15.22 to 1. The transmission also drives an accessory drive gear that powers the transmission oil pump, the hydraulic pump, and the rotor tachometer-generator. Two chip detector plugs are installed below the oil level sight gauge on the right side to detect metallic particles in the sump. If metallic chips are detected, the TRANS CHIP light on the caution panel will illuminate.

The transmission provides two stages of gear reduction with an overall gear reduction of 15.22 to 1.0. The first stage is located in the lower case and consists of an input gear, ring gear, and shaft support. The second stage of the transmission is located directly above the first stage and consists of the sun gear shaft, planetary gears, and ring gear. The input gear (figure 4-14), driven by the barbell shaft, is rotating at 6,000 RPM and the output to the rotor mast is rotating at 394  RPM.

Transmission Oil System
The transmission is lubricated by a wet-sump system and is serviced from the upper right side of the transmission casing (Figure 2-8). Transmission oil pressure is provided by a self-contained system with the oil pump immersed in the sump. The pump is located at the lower end of the transmission. The transmission oil pump also furnishes oil for the lubrication of the freewheeling unit that is mounted on the engine accessory gear case. A pressure line and a return line pass oil through the forward engine bulkhead to connect the transmission and freewheeling unit. (NATOPS)

Lubrication for the transmission is provided by a wet sump/pressure lubrication system which includes a pump, relief valves, filter, spray jets, temperature bulb, and an oil cooler (figure  4-2). The lower case of the transmission is the wet sump for the system, which has a total capacity of five U.S. quarts. Transmission Oil Schematic (Right)    First in the system is the oil pump, which is mounted internally in the transmission lower  case and is driven by the accessory gear drive. The accessory drive gear is splined to a shaft that passes through the oil pump. This shaft not only drives the internal oil pump; it also drives the hydraulic pump and the Nr tach generator, which are mounted piggyback with  each other. (Systems Book)

Transmission Oil Cooler
Oil temperature is automatically controlled by a thermostatically operated bypass valve that directs the flow of oil through the oil cooler when the oil is hot or around the oil cooler when cold. The oil then returns to the gearbox and is sprayed through jets onto the transmission gears and bearings.

Transmission Oil Pressure Gauge
The transmission oil pressure gauge, co-located with the transmission oil temperature gauge, is located on the instrument panel (Figures 2-3, 2-4, and 2-5). Transmission oil pressure is a direct-reading, wet-line system requiring no electrical power for operation. Pressure readings are indicated in psi.

Transmission Oil Pressure Caution Light
A caution light marked TRANS OIL PRESS is located on the caution light panel on the instrument console. The transmission oil pressure switch is installed in the transmission oil pressure indicator line and is connected to the caution light that illuminates when transmission pressure falls below 30±2psi.The TRANS OIL PRESS caution light is protected by the CAUTION LT circuit breaker.

Transmission Oil Temperature Gauge
The transmission oil temperature gauge, located on the instrument panel (Figures 2-3, 2-4,and2-5), is calibrated in degrees Celsius. An electrical resistance-type thermobulb located in the left side of the transmission transmits the oil temperature reading to the indicator unit. The transmission oil temperature gauge is protected by the ENG XSMN IND circuit breaker.

As oil enters the filter head, temperature is sensed by the thermobulb, which gives an indication on the oil temperature gauge in the cockpit.

Transmission Oil Temperature Caution Light.
The transmission oil temperature caution light marked TRANS OIL TEMP is located on the caution light panel on the instrument console. A transmission oil temperature switch located adjacent to the temperature bulb on the left side of the transmission closes when the temperature of the transmission oil rises above red line and illuminates the caution light. The TRANS OIL TEMP caution light is protected by the CAUTION LT circuit breaker.

If the oil temperature exceeds 110 degrees Celsius, the high temperature sensor switch closes a circuit that illuminates the  TRANS OIL TEMP caution light. In normal operation, a bypass valve allows oil to enter the filter.

Transmission Chip Detectors
Two electrical chip detectors are located on the lower transmission housing and are connected to the TRANS CHIP caution light to give evidence of metal particles in the transmission lubrication system. The TRANS CHIP caution light is protected by the CAUTION LT circuit breaker.

One of the detectors also serves as the drain plug for the transmission case (refer to figure 4-6). Some aircraft have an additional electric-magnetic chip detector on the upper port side. The accumulation of metal particles on the various chip detectors will indicate normal wear, as well  as excessive deterioration. In either case, maintenance personnel must determine the status of the aircraft.

=Sprag clutch Slippage= Sprag clutch slippage may occur following power-off maneuvers in which Nr and Nf have been split. When the twist grip is increased to full open, the pilot may experience: INDICATIONS:
 * Nf indication higher than Nr
 * Low torque indication
 * Ng and TOT indications lower than normal and not responsive to collective.

PROCEDURES: *1. Autorotate. *2. Twist grip — FLIGHT IDLE.

If time and altitude permit: *3. Twist grip — Smoothly Rotate to Full Open.

If Nf/Nr are married: *4. Collective — Increase.

If sprag clutch continues to slip: *5. Autorotate. *6. Twist grip — Closed.

If the sprag clutch reengages: *7. Land as soon as possible.

CAUTION: After completing the autorotative landing, ensure that the twist grip is secured. Failure to do so may result in sudden reengagement of the sprag clutch, causing severe damage to the drive system.

Note: Multiple attempts to reengage the sprag clutch are permitted dependent on time and altitude.

=Sprag Clutch Seizure= INDICATIONS:
 * Nf/Nr married during shutdown
 * Nf/Nr married above 100 percent during auto-rotational flight.

Note: In a normal autorotation, Nr and Nf may be matched together between 92- to 96-percent steady state. *1. Ensure twist grip is full open. *2. Land as soon as possible.

WARNING: If suspected during an autorotation, execute a waveoff before Nr decays below 85-percent.

=Main Drive Shaft Failure= INDICATIONS:
 * Nr decrease
 * Nf/Ng rpm increase
 * Left yaw
 * Loud bang/noise.

PROCEDURES: *1. Autorotate. *2. Twist grip — ADJUST to maintain Nf/Ng in operating range.

WARNING The engine must continue to operate to provide tail rotor drive. Tail rotor drive effectiveness may be lost if Nf is allowed to go below 80 percent.

When on deck: *3. Emergency shutdown — Complete.

=Imminent Transmission Failure= PROCEDURES: *1. Land Immediately. *2. Lock Harness.

WARNING Do not autorotate; minimize power changes.

=Over Torque= If any overtorque exceeding 110 percent, overspeed, or overtemp is observed, land as soon as possible.

=Icing= Operation of the engine during icing conditions could result in ice formations on the compressor front support. If ice were allowed to build up, airflow to the engine would be affected and engine performance decreased. Every effort must be made to remain clear of known icing conditions. The anti-ice system in this helicopter is to be used as a preventative measure only. Once ice has accumulated, the anti-ice system cannot be used as a corrective measure (will not deice). Intentional flight in any known icing condition (<4° in Visible moisture) is prohibited. For inadvertent flight in icing conditions, proceed as follows: PROCEDURES: *1. ENG ANTI-ICING — ON. *2. Pitot heat switches — Heat. (C)3. Alternate static port — As Required. If unable to remain clear of icing conditions: *4. Land as soon as possible. WARNING Monitor engine instruments and be prepared for partial or complete power loss.

=Ground Vortex= During transition to forward flight the pilot will encounter several phenomena exclusive to helicopter flight which, although encountered almost simultaneously, are discussed separately in  the following sections. The first is ground vortex. As the helicopter accelerates from a hover in ground effect to forward flight, benefits of ground effect can be lost at an altitude of less than 1⁄2 rotor diameter and airspeed between 5 and  20 knots. This is called ground vortex. As the helicopter moves forward, the rotor downwash mixes with increased relative wind to create a rotating vortex, which eventually causes an  increased downwash through the rotor system. This simulates a climbing situation, increasing power required. Eventually this vortex is overrun at a higher speed. These flow patterns are better described in figure 3-15.

=Simulated Engine Failure on Takeoff= The "Cut Gun" on takeoff is an instructor-demonstrated maneuver simulating a loss of power at low altitude.

PROCEDURES:

1. Start a transition to forward flight and climb to an altitude at or above 50 feet and no slower than 65 Knots. This is to ensure the maneuver entry is in the safe region of Height Velocity Diagram per Figure 4-6 of NATOPS manual, and follows a normal take off profile per CNATRA P-457 Rev (02-04) TH-57 Contact FTI Par. 407.

2. While maintaining the collective setting for climb power, rotate the twist grip to flight idle.

3. Commensurate with airspeed and altitude, lower the collective and adjust the nose attitude to control groundspeed and rate of descent. Monitor Nr and control with the collective.

4. Complete (as briefed) as either a power-recovery or a full autorotation.

AMPLIFICATION AND TECHNIQUE: The initial response required to successfully recover from an engine failure on takeoff will depend upon your nose attitude. If the aircraft is at or below the flare altitude, apply aft cyclic as necessary and lower the collective to maintain Nr. However, if the aircraft is above flare altitude, adjust the cyclic forward to maintain airspeed while lowering the collective to maintain Nr. Upon reaching the flare altitude, complete the autorotation using normal procedures.

-PAGE 6-2 in the CONTACT FTI.

=CRM Adaptability/Flexibility=

WHAT IS ADAPTABILITY/FLEXIBILITY?
 * Adaptability/Flexibility refers to the ability to alter a course of action when new information becomes available.

SITUATIONS THAT REQUIRE QUICK ADAPTATION
 * When Unbriefed Situations Arise
 * A Routine Mission Becomes an Emergency
 * Transitions Occur
 * A Crew Member is Incapacitated
 * Interactions are Strained

MAINTAINING ADAPTABILITY / FLEXIBILITY
 * Anticipate Problems
 * Recognize and Acknowledge any change
 * Determine if an SOP or Habitual Response is Appropriate
 * Offer alternative solutions
 * Provide and Ask for Assistance
 * Interact Constructively with Others

SETTING THE TONE FOR ADAPTABILITY/FLEXIBILITY
 * Establish an open, professional atmosphere
 * Ensure the crew understands the mission