MT-Propeller Service Letters

Service Letters

Download all Service Dokuments in zip.files (only for certified Service Stations)

No. Content Date of Revision
(.pdf, 250k)
List of Service Letter
download this list as .pdf file
June 14, 2023
(.pdf, 12k)
Replacing of lag screws part No. A-550-85 and part No. A-550-65 by lag screws part No. A-983-85 and part No. A-983-65.
Affected Propellers: All Constant Speed Propellers.
May 12, 1999
Aeroshell No. 5 is used instead of Aeroshell No. 6.
Affected Propellers: All Constant Speed Propellers. Replaced by Service Letter No. 21
May 12, 1999
(.pdf, 10k)
Modification of the pitch change pin location.
Affected Propellers: All Constant Speed Propellers.
May 12, 1999
Introduction of DF O-Rings.
Affected Propellers: All Constant Speed Propellers.
Replaced by Service Letter No. 14
May 12, 1999
(.pdf, 9k)
Replacing of screws part no. MS 35265-65/ A-1635-70 and washers part no. AN 960-10.
Affected Propellers: All Hydraulic Constant Speed Propellers.
May 12, 1999
(.pdf, 9k)
Modification of Counterweights A-597-B.
Affected Propellers: MTV-9-B-C/CL250-27, MTV-9-B-C/CL260-27
May 12, 1999
(.pdf, 19k)
Replacement of screws M3x10 by M3x12.
Affected Propellers: All Electric Constant Speed Propellers
March 05, 2003
(.pdf, 9k)
Introduction of Resin A 20 + Hardener B20
Affected Propellers: All natural composite blades
Nov 29, 1999
(.pdf, 9k)
Replacing of blade bearings A-317, A-233, A-004
Affected Propellers: All variable pitch propellers
Aug 27, 2001
(.pdf, 16k)
Teardown inspection at 1/3 TBO.
Affected Propellers: All Variable Pitch Aerobatic Propellers.
March 01, 2000
(.pdf, 9k)
Installation of standard electric pitch change motor
Affected Propellers: All Electric Constant Speed Propellers.
April 05, 2000
(.pdf, 8k)
Painting of Counterweights
Affected Propellers: All Counterweighted Propellers
July 11, 2002
(.pdf, 14k)
New blade seals in MT-Propeller constant speed propellers.
Affected Propellers: All MTV Constant Speed Propellers.
March 20, 2003
SL15 R1
(.pdf, 106k)
New counterweights
Affected Propellers: All MT-Propellers with the new counterweights installed
April 30, 2021
(.pdf, 9k)
Erosion Sheath on fixed pitch propeller
Affected Propellers: All Fixed Pitch Propellers with a Diameter > 69.3 inch
Feb 01, 2001
(.pdf, 13k)
Replacement of MTV-9/ -12/ -14/ -15 hub (serial numbers up to 97xxx).
Affected Propellers: MTV-9, MTV-12, MTV-14, MTV-15
March 09, 2011
SL18 R1
(.pdf, 70k)
Additional Installation of PTFE back up ring
Affected Propellers: MTV-9-( ), MTV-12, MTV-14-( )
July 29, 2015
(.pdf, 9k)
New Control Unit P-120-A (beginning with serial no. WA01-XXX)
Affected Propellers: All aeroplanes and motor gliders with an electrical variable pitch MT-Propeller with a Control Unit P-120-A.
Oct 24, 2001
(.pdf, 72k)
Replacement of the front plate of MTV-9-/MTV-12-/MTV-14-/MTV-16-( ) with new hub
Affected Propellers: MTV-9/ -12/ -14/ -16, standard, with feather and reverse (M) (P).
Feb 19, 2009
(.pdf, 21k)
Replacement of Aeroshell 5 by MT 2 Propeller Grease including improvement of viscosity Nov 04, 2002
(.pdf, 71k)
Leading edge installation
MT-Propeller Constant Speed Propeller Blades of type:
C188-18b, C190-18b, C193-18b, C198-25, ()225-37a, ()180-59, ()180-59b, ()183-17e (-A), ()183-59, ()183-59b, ()188-59b, CFLR250-55b
Affected Propellers: MT-Propeller Constant Speed Propeller
March 09, 2011
(.pdf, 14k)
Grease Leakage Problem.
Affected Propellers: MTV-12-B/180-17 installed on Diamond DA40 with Lyc. IO-360-M1A.
March 21, 2003
(.pdf, 14k)
Torque of Check Nuts and Slotted Nuts.
Affected Propellers: All hydraulic MTV-Propellers.
March 07, 2003
(.pdf, 20k)
Replacement of return spring, part no. A-085 by new return spring part no. D-389-K
Affected Propeller: MTV-6( )
Jan 28, 2004
(.pdf, 72k)
Front Plates
Affected Propeller: All hydraulic MTV-Propeller (except dual acting Walter Reverse Systems -R(W)) manufatured between Augst 1999 up to October 2004 (serial no. 99xxx to 04xxx)
Nov 12, 2004
(.pdf, 67k)
Cure date and shelf live of MT-Propeller O-Rings
Affected Propeller: All hydraulic and electric constant speed MT-Propeller.
Sept. 19, 2012
(.pdf, 36k)
Installation of oil cooler scoop P/N 763-8035-1/MT on Cessna U206 , TU206G (with Soloy Turbine PAC, FAA STC SA 3353 NM) equipped with 5-blade MTV-5-1-E-C-F-R(M)/CFR220-54 propeller
Affected Propeller: MTV-5-1-E-C-F-R(M)/CFR220-54
July 03, 2006
SL29 R6
(.pdf, 51k)
Additional application of carbon fiber plies on blade tip area Affected Propellers: MTV-15-B/210-58 and MTV-15-B/205-58 on Husky A1-( ) MTV-15-B/203-58 on ACA Scout MTV-15-C/200-50p / MTV-20-C/200-50p and MTV-15-( )/183-50 MTV-12-( )/( )180-57 Aug 27, 2021
(.pdf, 54k)
Fluid De-Ice Boot Installation on MT-Propeller Composite Blades June 18, 2009
(.pdf, 88k)
MTV-9-B-S/198-58B Rework and Modification of Blade Preload-Nut A-1368 and Blade Ferrule A-1367 Feb 12, 2008
SL32 R8
(.pdf, 1.9MB)
MT-, MTE and MTV-Propellers with natural Composite Blades
Aug 27, 2021
(.pdf, 980kb)
MT-, MTE and MTV-Propellers with natural Composite Blades
Nov 11, 2013
(.pdf, 980kb)
Performance of Minor Infield Repairs of the Natural Composite MT-Propeller Blades During the Operation Time between Overhaul Periods Dec 21, 2018
(.pdf, 71k)
Shrouded Propeller Installation (if not enough clearance between blade tip and shroud) Jan 20, 2009
(.pdf, 116k)
MTV-9-B-S/198-58B installed on Cessna 182 (SMA-Application) with Propeller hub A-926-2-( ) Oct 20, 2008
(.pdf, 145k)
MTV-6-( )-( )with Fluid Deice Systemn MTV-6-( )-( )-( ) propeller hub: A-900-I / A-1677 May 22, 2017
(.pdf, 63k)
All MT-Constant Speed Propellers
Cleaning of Parts and Hubs by Glass / Plastic Media Blasting
March 13, 2009
(.pdf, 90k)
Rework of Hub Inserts to Newest Technical Standard during next Overhaul and/or Repair
May 07, 2009
Propeller Governors for Electric Control P-857 / P-877 series
Correct Adjustment of Travel of Speed Change Nut
Dec 02, 2011
SL38 R2
(.pdf, 100k)
Procedure for the Installation of the Preload System P-890
Affected Proeller: MTV-12, MTV-14, MTV-22
Sept 09, 2014
SL39 Start Lock Springs
Exchange of Start Lock Springs, Identification of Springs
(for special customer only)
Oct 07, 2009
SL40 Propeller Governors for Electric Control P-853, P-877 series
Installation of the Flexible Max Speed Stop Modification “D”
(for special customer only)
Nov 10, 2009
SL41 R1
(.pdf, 140k)
Optional Replacement of Return Spring Part N. A-880 by new Return Spring Part No. A-1772 and A-1771-1
Affected Propeller: MTV-12-( )-C-F
June 23, 2015
(.pdf, 460k)
Propeller Designation System March 21, 2010
(.pdf, 90k)
Cure Date and Shelf Life of MT-2 Propeller Grease May 09, 2011
SL44 R1 Length of stainless-steel erosion protection sheaths for single blades May 25, 2020
SL45 R2 (Internal)
(.pdf, 40k)
Fittings installed on Unfeathering Accumulator P-893-( )/P-905-( ) on all Diamond DA42 with Thielert/Austro/Lycoming engines Sept 28, 2012
(.pdf, 40k)
Blade Seal Installation during Propeller Assembly Jan 14, 2013
SL49 R9
(.pdf, 1,5MB)
Re-Positioning of de-ice cables to improve long time wear. Feb 06, 2018
SL50 R2
(.pdf, 749kb)
Pitch change pin inspection during next overhaul or repair. March 20, 2023
SL51 R1
(.pdf, 53kb)
Installation of Protective Erosion Tape on De-Ice Boots
Affected Propeller: MTV-27-1-E-C-F-R(G)/CFRL250-55b
Affected Aircraft: DO228 series
March 17, 2016
SL51-1 R3
(.pdf, 60kb)

Installation of Protective Erosion Tape on De-Ice Boots
Pilatus PC 12 / KingAir 200 series / Beech 1900 series SA-227-AT/-AC/-BC/-TT/-CC/-DC/ SA-226-TB / Metro 3 / Merlin 4
Affected Propeller:
MTV-47-1-N-C-F-R(P)-( )/CFR260-361

Nov 10, 2020
SL52 R1
Optimum Installation of the Christen 801 Series Inverted Oil System in
Combination with MT-Propellers.
Affected Propeller: MTV-12-B-C/C183-17e
Affected Aircraft: Grob G115E
For special customer only
May 29, 2013
SL52-1 R1
(.pdf, 53kb)
Installation of P-447 Accumulator in Combination with MT-Propellers
Affected Propeller: MTV-12-B-C/C183-17e
Installed per EASA STC 10043263
July 30, 2015
(.pdf, 53kb)
Removal of Inner Propeller Spring on Counterweighted MT-Propeller
Affected Propeller: MTV-12-B-C/C183-17e
Installed per EASA STC 10043263
Nov 07, 2013
SL53 R4
(.pdf, 53kb)
Modification of Fluid Deice System
Affected Propeller:MTV-14-D/195-30b
Affected Aircraft: Cirrus SR22-( ) with Spinner Assy P-320-2
Aug 28, 2015
(.pdf, 53kb)
Replacement of parts during overhaul or repair
Affected Propeller: MTV-27-1-N-C-F-R(G)-J with blade type CFR285-82 or CFRL 285-82
Affected Aircraft: Jetstream 41
July 25, 2013
SL55 R5
Installation of Protective Polyurethane Tape on MTV-5-()/-27-() Hovercraft blades
Affected Propeller:
Affected Vehicle: Griffon Hovercraft
(This service Letter overwrites 55A)
Nov 13, 2015
SL56 R1
(.pdf, 53kb)
General Information for MT-Propeller trained Mechanics Possible Action against Dynamic Vibration on MT-Propeller
Affected Propeller: MTV-27-( ), MTV-25-( ), MTV-16-( ), MTV-5-( )
Dec 21, 2018
SL57 R1
(.pdf, 53kb)
Affected Propeller: MTV-27-1-N-C-F-R(G)-J/ CFR285-82 / CFRL285-82
with spinner assembly P-1152-( )
installed on Jetstream 41
Manufactured / overhauled or repaired before 12/2013.
March 17, 2015
(.pdf, 176kb)
Removal of inner propeller spring on counterweighted MT-Propeller
Affected Propeller: MTV-14-B-C/C190-17 on EXTRA 300 series, Cap 231/EX/232 Series
Aug 07, 2014
(.pdf, 176kb)
RCounterweight body crack inspection (Magnetic Particle Inspection)
Affected propeller: All counterweighted variable Pitch MT-Propeller
Feb 19, 2015
(.pdf, 176kb)
Moficiation of Counterweight Body A-1496-(C )Y( )
Affected Propeller:
MTV-16-1-N-C-F-R(P)/ CFRLD265-65
MTV-16-1-N-C-F-R(P)/ CFRLD280-65
June 11, 2015
(.pdf, 488kb)
Additional Secure of Motor Screws on Electric Motor P-820-( ) Aug 04, 2015
SL62 R1
(.pdf, 653kb)
Modification of the Starter Gear installed on Lycoming Engine for Electrically Controlled Variable Pitch Propeller Systems Affected Propellers: MTV-7-( ),MTV-10-( ), MTV-18-( ), MTV-23-( ) Sept 13, 2021
(.pdf, 653kb)
Inspection of Beta Valve P-846 / Prop Front O-Ring for possible Oil Leak Installed on RR250 engines
Affected Propellers:
Nov 02, 2016
(.pdf, 653kb)
Alternative Positioning of MT-Propeller Identification Label Affected Propellers:
All MTV-Propeller which have no identification label on the propeller blade
Feb 2, 2017
SL65 R1
(.pdf, 1.9MB)
Inner bearing Halves Inspection (Visual Inspection)
Affected Propellers:
All Hydraulically and Electrically Controlled Variable Pitch MT-Propeller As sharp edges were found on the split line of the inner bearing halves. (For certified service stations only, please log in)
March 15, 2021
SL66 R1
(.pdf, 155kb)
Outer Blade Bearings MTV-33, MTV-34, MTV-36 March 20, 2023
(.pdf, 270kb)
How to use the Anti Icing Liquid ICEX II (Goodrich) on MT-Propeller Blades Sept 26, 2017
(.pdf, 320kb)
Replacement of Electric Servo Motor Type 34L / 34LT / 35 NT
Installed on Electrically Controlled Variable Pitch MT - Propellers
Aug 24, 2017
(.pdf, 250kb)
Readjustment of the Low Pitch Stop Rods or Replacement of the Piston Extension P/N A-1020-A-42-L installed on MTV-9-( )-( )-R(M) propeller during the next Repair or Overhaul Feb 15, 2018
(.pdf, 83kb)
Propeller Snap Ring Inspection MTV-33-( ) and MTV-34-( ) Propeller Sept 10, 2018
SL71 R3
(.pdf, 100kb)
Governor jam relieve, adjustment of MIN and MAX RPM settings P-853-16 and -877-16 July 01, 2020
SL72 R2
(.pdf, 360kb)
Application of Expoxy Filler on Natural Composite Blades May 03, 2023
SL73 R1
(.pdf, 360kb)
Optional installation of the blade bearing A-1540 March 20,2023
(.pdf, 200kb)
Propeller Carbon Blocks C-131-3 used for MT-Propellers installed on PT6A-( ) engines Feb 25, 2021
(.pdf, 165kb)
Piston exchange for MTV-47-( ) series Issue Date June 14, 2023
(.pdf, 200kb)
Thicker Erosion Protection Sheaths on Fixed Pitch Propellers Aug 18, 2021
(.pdf, 110kb)
Length of the spinner fixture screws installed on spinner assembly P/N P-1741-( ) March 17, 2022
(.pdf, 486kb)
PT-6 Governor Reverse RPM-Limitation Check (Py Air-Bleed Function) Affected Propeller: MTV-16-1-E-C-F-R(P)/CFR240-55( ) on PT6-( ) engines May 02, 2022
SL 79
(.pdf, kb)
MT-Propeller New Piston O-ring for Turboprop Installations Affected Propeller: All MT propellers MTV-( )-R(G), -R(P), -R(A), -R(W) -R(GE), installed on Garrett / Pratt & Whitney / Allison / Walter / GE engine applications September 01, 2022
(.pdf, kb)
Possible Grease Leak and High Friction of Blade Preload after or during Assembly Affected O-rings: All blade O-rings, C-057-( )-R, all models of a certain production batch. November 14, 2022