Posts Tagged "MPD"

Rotax 912 and 914 Engines: Reciprocating Engine – Valve Push Rod Assembly – Inspection / Replacement

Rotax 912 and 914 Engines: Reciprocating Engine – Valve Push Rod Assembly – Inspection / Replacement

Applicability: Rotax 912 iS Sport, 912UL, 912ULS, 914UL engines. For Serial numbers affected refer to Rotax SB SB-912 i-008iS/SB-912-070UL / SB914-052UL at latest revision

Reason:  Power loss and engine RPM drop have been reported on Rotax 912/914 engines in service. It has been determined that, due to a quality control deficiency in the manufacturing process of certain valve push-rod assemblies manufactured between 08 June 2016 and 02 October 2017 inclusive, partial wear on the rocker arm ball socket may occur, which may lead to malfunction of the valve train. This condition, if not detected and corrected, may lead to rough engine operation and loss of power, possibly resulting in a forced landing with consequent damage to the aeroplane and injury to occupants. To address this potential unsafe condition, BRP-Rotax issued Service Bulletin (SB) SB-912 i-008 / SB-912-070 / SB-914-052 (single document), providing applicable instructions. For the reason described above, this MPD requires a one-time inspection and, depending on findings, replacement of affected parts. This MPD also prohibits installation of affected parts on an engine. This MPD, for the uncertified engine variants, mirrors the EASA AD 2017-0208, which was for the certified engine variants.

Compliance/ Action: Required as indicated unless accomplished previously:

Note 1: Valve push-rod assemblies Part Number (P/N) 854861 are hereafter referred to as “valve push-rod”.

Note 2: BRP Rotax SB-912 i-008 / SB-912-070 / SB-914-052 (single document) is hereafter referred to as “the SB” (see link below).

Note 3: BRP Rotax SB-912 i-008iS / SB-912-070UL / SB-914-052UL (single document) is hereafter referred to as “the Applicability SB”

Note 4: Group 1 engines are those having a serial number (s/n) as listed in the Applicability SB (see Note 3); or an engine, having any s/n, on which a valve push-rod (see Note 1) has been replaced in service between 08 June 2016 and 18 February 2018 inclusive. Group 2 engines are those that are not Group 1.

Inspection: (1) For Group 1 engines (see Note 4): Within the compliance time identified in Table 1 below, as applicable, visually inspect the push-rod ball sockets of each valve push-rod in accordance with the instructions of the SB.

Table 1 – Visual Inspection of Affected Assembly

Engine Flight Hours (FH) since first installation on an aircraft Compliance Time

 

160 FH or less

 

Before exceeding 170 FH since first installation of the engine on an aircraft, or within 3 months after 18 February 2018, whichever occurs first.
More than 160 FH

 

Within 10 FH or 3 months, whichever occurs first after 18 February 2018.

Corrective action: (2) If, during the inspection as required by paragraph (1), a valve push-rod having black surface is detected (reference Fig. 1 in the SB), before next flight, replace that valve push-rod and its affected parts (see Note 5) with serviceable ones in accordance with the instructions of the SB.

Note 5: Affected parts are listed in Table 2.

Table 2 – Affected Part

Part

 

Part Number

 

Vale push-rod assembly

 

854861

 

Rocker arm left

 

854383

 

Rocker arm right

 

854393

 

Part installation: (3) For Group 1 and Group 2 engines: From the 18 February 2018, it is prohibited to install on any engine a valve push-rod (see Note 1) manufactured between 08 June 2016 and 02 October 2017 inclusive.

ENSURE COMPLIANCE WITH THIS MPD/SB IS RECORDED IN THE AIRCRAFT LOGBOOK

Further information is available at the following links:

Service Bulletin Information Release

The Service Bulletin

The UL Service Bulletin 

EASA Airworthiness Directive (Certified Aircraft Only, included for Reference)

UK CAA Mandatory Airworthiness Directive

Ikarus C42 Service Bulletin for all models

High hours examples of C42 aircraft have exhibited cracks emanating from the corners of the cut-outs in the main fuselage tube where the nose undercarriage leg and the A-strut are attached. The problem appears primarily to affect high hours early examples of the C42 on which the affected cut outs were made manually. Later models have machined cut-outs which are thought less likely to exhibit the cracking problem. More recently the A-strut attachment has been re-designed and there are no cut-outs for this item in the fuselage tube. At least for the initial issue of the service bulletin, all C42 aircraft must be inspected regardless of the build standard and manufacturing standard of the fuselage tube. If such cracks were allowed to propagate, the structural integrity of the nose undercarriage leg, A-strut and engine mountings may be compromised.

Compliance is required as follows, unless previously accomplished:

  1. For aircraft with over 2000 hours of operation, carry out the inspection in paragraph 5 of this MPD before further flight.
  2. For aircraft with over 1000 hours of operation, carry out the inspection in paragraph 5 of this MPD at the next annual inspection or the next 100 hour inspection, whichever occurs first.
  3. Repeat the inspection carried out under paragraph 1 or paragraph 2 of this MPD at 500 hour intervals.
  4. If the main fuselage tube has been replaced in an aircraft, the requirements in paragraphs 1, 2 and 3 of this MPD are applicable from the time of installation.
  5. Visually inspect the main fuselage tube, inside and outside surfaces, in the vicinity of the nose undercarriage leg and Astrut (if applicable) attachment cut-outs for cracking. See example photographs in the referenced Owner’s Service Bulletin. To facilitate the inspection the upper and lower cowlings must be removed as well as the sound deadening foam on the cockpit side of the firewall. If there is doubt whether there is cracking, dye penetrant crack detection may be used in addition to the visual inspection.
  6. The aircraft owner may carry out the inspection in paragraph 4, if they consider themselves capable. Alternatively, a BMAA or LAA inspector may carry out the inspection.
  7. If any cracks are found, ground the aircraft then inform Red Aviation and obtain and implement a repair scheme before further flight.

More details at http://bmaa.org/files/osb_29_main_fuselage_tube_cracking_issue_1.pdf and http://publicapps.caa.co.uk/docs/33/EmergencyMPD2016004E.pdf