206LLongRanger

A blocked oil line restrictor in the freewheel lubrication system can cause unsafe conditions. This AD requires inspecting and cleaning the oil supply restrictor to the freewheel assembly.

Driveshafts on certain Bell helicopters may crack or develop loose fasteners, which could cause loss of main rotor drive and force an emergency landing. This AD requires inspection of affected driveshafts for cracks, loose fasteners, or red powder residue, with replacement if any defects are found.

Certain Bell Model 206L-1, 206L-3, and 206L-4 helicopters experience third-stage engine turbine wheel failures due to excessive vibrations at certain engine speeds. This AD requires installing a placard and revising the rotorcraft flight manual limitations section.

Certain main rotor blades were manufactured with an oversized spar spacer that could fail and cause loss of control. This AD requires measuring the spar spacer on each main rotor blade, reidentifying affected blades, and reducing their life limits.

Certain Bell 206L helicopters may have a cracked or damaged tailboom upper left attachment fitting that could lead to loss of the tailboom and control. This AD requires inspecting the fitting for cracks, loose rivets, corrosion, and other damage.

Emergency floats on certain Bell helicopters may fail to deploy due to defective inflation hoses. This AD requires inspecting, labeling, and replacing the float inflation hoses to ensure the emergency flotation system functions properly.

Certain freewheel aft bearing caps were manufactured without a lubrication channel, which could cause freewheel unit failure and loss of helicopter control. This AD requires replacing or reworking the affected aft bearing caps.

Bearings in certain Bell helicopters may not be properly staked and can migrate from their correct position, potentially causing bearing and assembly failure and loss of helicopter control. This AD requires inspecting each bearing to verify proper staking and replacing any bearing or assembly that is not properly staked.

The engine auto-relight kit control box chipset does not meet temperature range requirements, potentially causing system malfunction and engine relight failure. This AD requires replacing the affected control boxes to restore auto-relight system reliability.

Certain hydraulic servo actuator assemblies may have a loose nut, shaft, and clevis due to improper lock washer installation, which could cause servo failure and loss of helicopter control. This AD requires inspecting these servos for loose parts, modifying or replacing them as necessary, and reidentifying the servo.

Unfiltered turbine outlet temperature warning lights create glare and reflections that degrade pilot vision when using night vision goggles. This AD requires inspecting for an unfiltered TOT warning light and installing an NVIS filter if found.

Main rotor blades on certain Bell helicopters have failed due to fatigue cracking, causing loss of control. This AD reduces the life limit of affected main rotor blades to prevent blade failure.

Helicopter occupants may not be aware of the location and operation of external liferaft inflation handles, preventing proper deployment during water emergencies. The AD requires adding placards to identify the location and operation of liferaft external inflation handles and replacing liferaft operation placards to state that external liferafts are installed.

Tail rotor blade tip weights can separate from blades during flight, causing vibration and potential loss of control. This AD requires inspection and replacement of affected tail rotor blades to prevent blade loss.

Fatigue cracks have been found in tailboom skins around nutplates and drive shaft cover retention clips, which can lead to tailboom failure and loss of helicopter control. Operators must visually inspect the tailboom for cracks and corrosion at specified intervals using magnification, or replace it with an airworthy tailboom.

A bearing may be incorrectly installed in the cyclic control lever assembly, which could lead to bearing failure and loss of helicopter control. Before further flight, inspect each cyclic control lever assembly with less than 50 hours time-in-service to verify it is correctly installed and properly staked.

Certain tail rotor blade tip weights may depart from the blade during flight due to missing adhesive on the tip weight screw, affecting helicopter controllability and structural integrity. Operators must replace affected blades with airworthy blades that do not have serial numbers listed in the Rotor Blades, Inc. document attached to the applicable Bell Helicopter service bulletins.

Some helicopters have an improperly installed tailboom attachment bolt in the upper left-hand tailboom attachment fitting that does not meet design criteria. The AD requires correcting the installation of the tailboom attachment bolt to meet design specifications.

Horizontal stabilizers on certain Bell helicopters may have manufacturing flaws that lead to skin cracking and structural failure. The AD requires inspection and correction of these defects to prevent horizontal stabilizer failure.

Tail rotor blades on certain Bell 206 helicopters can develop skin cracks near the balance weight, potentially leading to blade failure and loss of control. The AD requires inspection of affected blades for deformation and cracks, with replacement of any defective blades before further flight.

Fuel nozzle screens can contaminate and collapse, causing sudden loss of engine power and uncommanded shutdown. This AD requires inspection of the fuel nozzle screen for contamination and replacement of affected fuel nozzles with a new design, with cleaning of the aircraft fuel system if contamination is found.

Magnetic brake adjustable stop screws on certain Bell 206L helicopters can back out, limiting control arm travel and potentially causing loss of control. This AD requires a one-time inspection of the stop screws, repair of any damage, reinstallation with proper adhesive, and adjustment of arm assembly travel with slippage marks.

Certain chip detectors may have poor or no continuity between the insert and housing, preventing proper indication of component failure and risking loss of control. The AD requires continuity testing of chip detectors, temporary repair of unairworthy units, and replacement of any previously repaired chip detectors.

Cracks have been found in tailboom skins of certain Bell 206L helicopter models, which could lead to tailboom separation and loss of control. Operators must inspect the tailboom for cracks and modify or replace it as necessary, with a terminating action available.

Third stage turbine wheels with certain serial numbers may fracture, causing uncommanded engine shutdown. Remove affected turbine wheels from service before exceeding new reduced life limits and implement a drawdown program for wheels exceeding new lower limits.

Main rotor trunnions are subject to fatigue cracks that can lead to failure and loss of helicopter control. Operators must retire affected trunnions based on time-in-service limits.

The tail rotor yoke on Model 206L-4 helicopters with the High Altitude Tail Rotor Kit is susceptible to failure from excessive bending loads caused by ground strikes or hard landings. The AD requires installing a high altitude tail rotor static stop yield indicator and performing preflight checks to detect overload conditions.

A raised forging boss on the collective lever assembly could interfere with the swashplate outer ring, potentially damaging flight controls and causing loss of control. Operators must inspect the collective lever assembly for a raised forging boss and adequate clearance, then modify any non-compliant assemblies before further flight.

The main rotor mast or trunnion may experience fatigue failure, which could result in loss of the main rotor system and loss of control of the helicopter. Operators must establish component history cards using the Retirement Index Number (RIN) system to track accumulated RIN and enforce retirement lives for affected masts and trunnions.

Two types of collective idler links and collective levers are manufactured from different materials but share the same part numbers, creating confusion about retirement lives. The AD requires reducing retirement lives for certain links and levers and re-identifying them to prevent failure and loss of helicopter control.

Certain Allison Engine Company 250-B and 250-C series engines can experience leaking main fuel control bellows assemblies, causing uncommanded minimum fuel flow and loss of engine fuel flow control. This AD requires replacing beryllium copper MFC bellows assemblies with Inconel 718 stainless steel welded MFC bellows assemblies.

False engine-out warnings may occur during autorotation practice with the Allison 250-C20R engine power-out warning sensor on these helicopters. The AD requires a revision to the Limitations section of the STC Rotorcraft Flight Manual Supplement to alert pilots of this condition.

Airmen have inadvertently moved the fuel valve switch to the OFF position, risking engine failure and forced landings. This AD requires installing a protective mechanical guard on the fuel valve switch to prevent accidental operation.