ALERT SERVICE BULLETIN206L-19-182
2 April 2019
MODEL AFFECTED: 206L, 206L-1, 206L-3 and 206L-4
SUBJECT: TAIL ROTOR BLADE ROOT END, INSPECTION OF
HELICOPTERS AFFECTED: Serial numbers 45001 through 45153, 46601; through 46617, 45154 through 45790, 51001; through 51612, and 52001 through 52496.
COMPLIANCE: Within 100 flight hours or 90 days, whichever occurs first after the release date of this bulletin.
Bell has become aware of a condition that affects the installation of the pitch horn assembly to tail rotor blade root end. Per the assembly instructions, sealant is applied to cover any remaining bare unpainted sections of the tail rotor blade root end. It is possible that some tail rotor blade assemblies delivered are missing this sealant.
This bulletin provides instructions to inspect for possible corrosion or damage on any exposed bare metal surfaces with a subsequent requirement to apply sealant to protect the area.
Applicability of this bulletin to any spare part shall be determined prior to its installation on an affected helicopter.
The engineering design aspects of this bulletin are Transport Canada Civil Aviation (TCCA) approved.
Approximately 1 man-hour is required to complete this bulletin. This estimate is based on a hands-on time and may vary with personnel and facilities available.
There is no warranty credit applicable for parts or labor associated with this bulletin.
The following material is required to accomplish this bulletin, but may not require ordering, depending on the operator’s consumable material stock levels. This material may be obtained through your Bell Supply Center.
2 OZ (1)
1 GAL (1)
5 GAL (1)
Alcoholic Phosphoric Cleaner
1 GAL (1)
Abrasive Cloth or Paper
Chemical Film Material
1 QT (1)
1 GAL (1)
Cloth, Cleaning, Low-Lint
* C-XXX numbers refer to the consumables list in the BHT-ALL-SPM, Standard Practices Manual
NOTE 1: The quantity indicated is the format the product is delivered in. Actual quantity required to accomplish the instructions in this bulletin may be less.
WEIGHT AND BALANCE:
ELECTRICAL LOAD DATA:
BHT-206L-MM Maintenance Manual
BHT-206L1-MM Maintenance Manual
BHT-206L3-MM Maintenance Manual
BHT-206L4-MM Maintenance Manual
1.Prepare the helicopter for maintenance.
2.Visually gain access to the root end of both tail rotor blades (Figure 2).
a.Clean affected area with a clean cloth (C-516) moistened with aliphatic naphtha (C-305). Dry the surfaces with a dry clean cloth (C-516) before the aliphatic naphtha (C-305) evaporates.
b.Confirm there is no exposed unpainted tail rotor blade root end surfaces adjacent to the pitch horn (Figure 1).
c.If surfaces are found properly sealed (Figure 2), go to step 3.
d.If some bare metal surfaces are found exposed (Figure 1), inspect for corrosion.
(1)If no corrosion is found, apply a smooth coat of sealant (C-308) to all sections of unpainted surfaces of tail rotor blade root end. Blend into pitch horn face and fair smooth (Figure 2). Allow sufficient time for sealant (C-308) to cure before flight. Go to step 3.
(2)If surface corrosion is present on tapered area of the aluminum butt block of the tail rotor blade (Figure 3), remove blade(s), inspect, repair and refinish blade(s) (BHT-206L-MM, Chapter 65; BHT-206L1-MM-1, Chapter 65; BHT- 206L3-MM-7, Chapter 64; BHT-206L4-MM-7, Chapter 64, as applicable).
(3)Install blade(s) (BHT-206L-MM, Chapter 65; BHT-206L1-MM-1, Chapter 65; BHT-206L3-MM-7, Chapter 64; BHT-206L4-MM-7, Chapter 64, as applicable).
3.Make an entry in the helicopter logbook and historical service records indicating compliance with this Alert Service Bulletin.
FIGURE 1 - Tail Rotor Blade Root End without Sealant
FIGURE 2 - Tail Rotor Blade Root End with Sealant Applied
FIGURE 3 – Example of Tail Rotor Blade Root End Tapered Aluminum Butt Block
About Aerochine Aviation Limited
Aerochine Aviation Limited or Aerochine is headquartered in Hong Kong Special Administrative Region (HKSAR) with offices in Beijing, Shanghai and Shenzhen. With its wholly owned subsidiaries in Ningbo and Zhenjiang, Aerochine put extraordinary effort in providing holistic customer services to clients including aircraft sales & leasing, sales & delivery of spare parts, as well as aircraft maintenance.