2 TH-57 NATOPS Change summary TH-57 NATOPS ConferenceConducted May 2012Approx. 30 attendees from TRAWING FIVE, NAVAIR, CNATRA, Bell, Naval Safety Center, Fidelity, L-3, HX-21 and CRM CMD SchoolDiscussed approx. 60 NATOPS changes that were submitted since the previous publication of the 2010 TH-57 NATOPS Manual.Major changes presented in the brief; minor word changes not listed.
3 PrefaceWarning - Explanatory information about an operating procedure, practice, or condition, etc., that may result in injury or death, if not carefully observed or followed.Caution - Explanatory information about an operating procedure, practice, or condition, etc., that may result in damage to equipment, if not carefully observed or followed.Note - Explanatory information about an operating procedure, practice, or condition, etc., that should be emphasized.Update of definitions from OPNAVINST U
4 CH 2 2.8 Fuel Supply System 2.11.3 Directional Control Pedals The fuel filter assembly and single- or dual-element engine-driven fuel pump, which operates at 700 +/- 50 psi, are integral units mounted on the aft left end of the engine.Directional Control PedalsNote - The pedal adjusters should not be set full aft as the pedal force trim switch will disengage the yaw force trim and the AFCS yaw axis (TH-57C).Engine driven fuel pump limits – same limits, edited to match format of other limits.Control pedals – clarification of note.
5 CH 4 Fig 4-3 Instrument Markings 4.4 Rotor Limitations Note – 22 VDC Minimum for battery start4.4 Rotor LimitationsPOWER ON: Minimum Nr is 97 percent. Maximum continuous Nr is 100 percent.POWER OFF: The normal operating range is 90 to 107 percent Nr. Transient allowable Nr is 107 to 114 percent for 5 seconds.Concorde Batteries – All aircraft batteries have been changed within the last year. New limit for battery start is 22 Vdc.Rotor Limitations – Accurately reflects limitations from Bell Flight Manual. Limitations now distinguish between power-on and power-off.
6 CH 6 NATOPS Brief 126.96.36.199 Conduct of Flight 188.8.131.52 Emergencies 11. Notice to Airmen (NOTAMS).Emergencies1. Actual2. Simulated3. Inadvertent IMC4. Ditching/emergency landing5.Emergency egressChecking NOTAMS is required per OPNAVINST U as are fuel and weather requirements which are included in the brief. This is also aligned with Fleet NATOPS Manuals.
7 CH 7 Preflight Inspection 7.9 Start 7.10 Pretakeoff 7.6.2 Cockpit 5. BAT Switch – ON. Check minimum 22 Vdc. If performing a battery start, check minimum 22 Vdc, if voltage is less than 22 Vdc, plan for GPU assisted start; if battery voltage is less than 18 Vdc, maintenance action is required7.9 Start7. Engine Start – Completef. Twist grip – flight idle at a minimum of 12 percent Ng.7.10 Pretakeoff16. Twist grip – Full open.Caution – When accelerating the rotor system during the initial rotor engagement or after power-off maneuvers, exceeding 40 percent torque may induce engine chugging which may induce a compressor stall.Preflight inspection of the aircraft’s battery now reflects new limits of Concorde batteries.Engine start – Clarification of NATOPS procedure. Fuel can be introduced at a minimum of 12% Ng, not to be confused with a range of 12-15% Ng.This Caution applies to accelerating the twist grip after all power-off maneuvers, not just full autos. The caution also clarifies that this could lead to engine chugging and eventually a compressor stall.
8 CH 7 Post Takeoff Checklist – Removed Health Indicator Test (HIT) Checklist – RemovedRemoval of Post Takeoff Checklist – Safety of flight. The Post Takeoff Checklist is a substitution for standard responsibilities as a pilot. These responsibilities include ensuring the aircraft is full systems and not indictating impending system failure.Removal of HIT Checklist – This test was initiated and designed by local maintenance contractors to aid in preventative maintenance. Aircrew should not treat locally derived baseline values as NATOPS limitations.
9 CH 11 Flight Characteristics Loss of Tail Rotor Authority Recovery procedures moved to CH 14 for the following:Uncommanded right roll during flight below 1gVortex Ring StateRotor blade stallLoss of Tail Rotor AuthorityAmplifying information explaining the differences between Loss of Tail Rotor Authority (LTA) and Loss of Tail Rotor Effectiveness (LTE).These emergency procedures should be included in CH 14, In-flight Emergencies.Amplifying information taken from the Helicopter Aerodynamics Workbook to alleviate confusion between LTA and LTE.
10 CH 12 Battery HOT Battery TEMP BAT Switch – OFF. Land as soon as possibleNote – Switching the Main Battery Off opens the main battery relay, which causes the “STBY BATT ON” light to illuminate. As long as the ESS No. 1 bus is being powered normally, the standby battery will not be depleted.Battery TEMPBAT Switch – OFF. Flight may be continued.Note – Same as above
11 CH 14Compressor StallCompressor stalls can very in severity, duration and recoverability. A compressor stall may present itself as a single pop, a sustained rumble or a series of loud bangs. The engine instruments may fluctuate, spike, or exceed limits, and the aircraft may become uncontrollable. As a result, recovery and subsequent landing will vary based on the severity of the stall, aircraft controllability and pilot experience. Often a reduction in collective will clear the stall. However, twist grip reduction may be required. Depending on time, altitude and suitability of the landing site, the pilot may attempt to increase the twist grip after the stall has cleared to effect a safe landing.Amplifying information on Compressor Stalls.
12 CH 14 Compressor Stall cont. Note – Bleed valve flutter is a mild pop or series of pops and may occur while opening the twist grip. This bleed valve flutter is considered normal as the bleed valve is operating as designed. The bleed valve flutter may cause slight momentary TOT and torque changes. Any additional indications should be reason to classify this as a compressor stall.Indications of a Compressor Stall:Popping, rumbling or loud bangingAbnormal vibrationsRapid rise or fluctuations in TOTTorque fluctuations with yaw kicksNg fluctuationLoss of powerAmplifying information describing the difference between Bleed Valve Flutter and Compressor Stalls.
13 CH 14 Compressor Stall Procedures: *1. Collective – Reduce *2. ENG Anti-ice switch – ON*3. Cabin Heat Valve – ONIf compressor stall persists and aircraft is uncontrollable:*4. Autorotate*5. Twist grip – Flight IdleNote – Depending on the time, altitude and suitability of the landing site, the pilot may attempt to increase the twist grip after the compressor stall has cleared to effect a power-on landing. Increasing the twist grip may re-aggravate the compressor stall.If compressor stall clears or aircraft is controllable:*6. Land as soon as possible.ENG anti-ice and cabin heat valve switches to be turned on to lessen the compressor stall by decreasing the pressure upstream.
14 CH 14 Underspeeding Nf/Nr Procedures If the pilot inadvertently rotates the twist grip out of the FULL OPEN position, it will create conditions that resemble underspeed indications. If the aircrew determines these conditions were induced by the pilot, flight may be continued once conditions return to normal.Procedures*1. Collective – Lower as required to maintain a minimum of 90% Nr.*2. Twist grip – Full open.*3. GOV RPM – Full increaseIf underspeed persists:*4. Check power available with Nr in limitsIf power is not sufficient:*5. AutorotateIf power is sufficient:*6. Land as soon as possible.Amplifying information explaining that the twist grip being inadvertently rotated out of full open is not a true underspeed. If conditions can be brought back to normal by rotating the twist grip back to full open, flight may be continued.In an underspeeding condition, the collective needs to be lowered (more specific than “adjust”).
15 CH 14 Power Required Exceeds Power Available Indications: Uncommanded descent with torque at maximum availableRotor droopLoss of Tail Rotor authorityProcedures:*1. Collective – Lower as required to maintain a minimum of 90% Nr.*2. Twist grip – Full open*3. Angle of bank – Level the wings*4. Airspeed – Adjust to 50 KIAS (minimum power required airspeed)*5. Jettison – As requiredIf impact is imminent:*6. Level the aircraft to conform to terrain.*7. Cushion the landing.Clarification of indicationsCollective needs to be lowered to maintain Nr (more specific than “adjust”)Reordering of steps to a more logical sequence. Leveling the wings first will be more efficient to regain power margin than the time that may be required to achieve 50KIAS.
16 CH 14 Dynamic Rollover (New Emergency Procedure) Indications: Excessive roll rates about a pivot point when lift approx equals weightLateral control becomes sluggish or ineffectualCyclic contacts lateral stopProcedures:*1. Collective – Reduce to stop the roll*2. Cyclic – NeutralWarning: With one skid on the ground and thrust approximately equal to weight, if the lateral control becomes sluggish or ineffectual, contacts the lateral stop, or bank angle or roll rates become excessive (15 or 10 degrees per second respectively), the aircraft may roll over on its side.Previous NATOPS Manuals have discussed the characteristics of Dynamic Rollover in CH 11, however no emergency procedure existed.
17 CH 14 Engine Overspeed Procedures: *1. Twist grip – Reduce (to maintain Nf /Nr in operating range)*2. Collective/Twist grip – CoordinateNote – The Nf overspeed must be controlled by coordinating collective and twist grip.*3. Land as soon as possible.An overspeed is likely due to an Nf Governor failure. Reducing the twist grip as the first step will bring the governor into the manual range while at the same time lowering the Nr.Old procedures were initiated by raising the collective until the Nr is lowered back into the normal operating range. This presents the risk of overtorqing the aircraft.
18 CH 14 Engine Restart in Flight *1. Autorotate *2. Starter – Engage *3. Twist grip – Check, Full openNote: The twist grip can be left in the full open position since fuel flow during the start will be on the normal acceleration schedule.If light-off does not occur:*4. Twist grip – closeNote: If time and altitude permit, multiple attempts can be made to perform a normal start.If light-off occurs:*5. Twist grip – Full open*6. Land as soon as possible.Once established in an autorotation, immediately engage the starter if conditions allow. Checking Nf above 12% is irrelevant considering fuel flow will be on the normal acceleration schedule.Checking the twist grip full open ensures fuel is being introduced in the event that a student inadvertently closed the twist grip which caused the flameout.If light off does not occur, closing the twist grip will ensure fuel is secured for the landing portion of the autorotation.
19 CH 14 Main Drive Shaft Failure *1. Autorotate *2. Twist grip – Adjust, if necessary, to maintain Nf in operating rangeWarning: The engine must continue to operate to provide tail rotor drive. Tail rotor effectiveness may be lost if Nf is allowed to go below 80 %.Note: The Nf governor should bring the Nf back to 100% with the twist grip full open.When on the deck:*3. Emergency shutdown - CompleteClarification of NATOPS procedure. If the governor returns the Nf to 100%, there is no need to reduce the twist grip.
20 CH 14 Mast Bumping Indications: Sharp, two-rev knocking Procedures: *1. Establish positive g load and/or balanced flight (as required)*2. Land immediatelyNote: If mast bumping occurs on the deck, maintenance action is required prior to flight.Previous Mast Bumping emergency procedure was cumbersome. A thorough discussion already exists in CH 11. Being able to recover an aircraft is integral to being a pilot (Similar to “recover aircraft” step of Hydraulic power cylinder malfunction).
22 CH 14 Complete Loss of Tail Rotor Thrust In a hover: *1. Twist grip – Flight idle*2. Cyclic – Eliminate drift*3. Collective – Increase to cushion landingTransition to forward flight or hover/air taxi:*2. Cyclic – Eliminate sideward driftThe twist grip at flight idle leaves very little torque on the aircraft, and is more realistic to accomplish than closing the twist grip completely during a time-critical situation of complete loss of tail rotor thrust.
23 CH 14 Complete Loss of Tail Rotor Thrust At Altitude: *1. Autorotate If yaw is not controllable:*2. Twist grip – Flight idle immediatelyIf yaw is controllable:*3. Continue powered flight and set up to a suitable landing area at or above minimum rate of descent autorotational airspeed.Warning – Autorotation may be the safest option. Attempting to control a loss of tail rotor thrust in powered flight requires considerable skill and may result in loss of aircraft control.*4. Autorotate*5. Twist grip – Rotate to flight idle prior to touchdown.Safety of Flight. As the Warning states, attempting to control a loss of tail rotor thrust in powered flight requires considerable skill and may result in loss of aircraft control. Autorotation may be the safest option.Aligns with procedures in Bell Flight Manual.
24 CH 14 Single Instrument Indications If a DC powered instrument fails, check for a popped circuit breaker. If operation is restored, by resetting the circuit breaker, flight may be continued.TorquemeterIf the torquemeter is unusually low or falls to zero with a corresponding digital readout, it is probable that the torque line has ruptured. A restrictor fitting in the wet line will slow the rate of engine oil loss, but will not stem the flow.*1. Monitor engine instruments*2. Land as soon as possibleClarification of NATOPS procedure
25 CH 14 Single Instrument Indications Torquemeter The torquemeter incorporates a transducer between the wet line and the gauge. If the needle falls to zero and the digital readout is extinguished, the cause is a loss of electrical power to the indicator.Monitor engine instrumentsCheck TRQ circuit breaker – InIf circuit breaker resets:3. Flight may be continued.If circuit breaker was not popped or does not reset:4. Land as soon as practicalClarification of NATOPS procedure.
26 CH 14 Single Helicopter Inadvertent IMC Procedure Establish an instrument scan and balanced flightTurn away from and/or climb above obstacles of immediate concern.Regain VMC if able.Warning – Entry into an unusual attitude has proven to be likely during Inadvertent IMC entry. This is due to spatial disorientation resulting from bank angle control reversal error and the psysiological tendency to apply aft cyclic and decelerate upon entry.If unable to regain VMC:ATC notify and gain IFR clearance if necessary.Previous NATOPS Manuals included Inadvertent IMC procedures for flights of two and four aircraft, however no procedure single helicopter IIMC entry.
27 CH 16Emergency Ground EgressSame procedure, all memory items
28 CH 20 Cockpit Management Operational Risk Management Crew Resource ManagementAircrew Authority and Operational PositionsChecklist ProceduresMission Specific CRM ProceduresMultiple changes.