MANDATORY BULLETIN. Concerns: L-420 airplanes and B N windshield wipers (spare parts).

Transcription

1 MB No.: L-420/020a MANDATORY BULLETIN Concerns: L-420 airplanes and B N windshield wipers (spare parts). Subject: Reason: Check and possible replacement of windshield wiper dowels. Occurrence of incorrectly clinched dowels. To be carried out at the latest by: Check - during 10 calendar days. Replacement - according to the bulletin text. To be carried out by: Organization certified for periodic maintenance of L-420 airplanes. Costs to be covered by: Necessary material to be delivered by: Operator. Aircraft Industries, a.s., Kunovice, Czech Republic against order. Bulletin becomes effective: On the date of its issue. Total No. of pages: 5... Released: Jaroslav Vrána Head of airworthiness dept. Technical content of this document has been approved based on the Design Organization Approval No. EASA.21J.119. May 28, 2014 Q 0501 Př.2/C Aircraft Industries, a.s., Kunovice, Czech Republic, phone: , fax: , ots@let.cz

2 PERFORMANCE: mandatory 1. INSTRUCTIONS FOR PLANNING A. CONCERNS 1. Airplane Model L Version / S/N All S/N and B N windshield wipers (spare parts) 3. Qualification for Implementation No special requirements. 4. New Equipment B. REASON Occurrence of incorrectly clinched dowels. C. APPROVAL This Bulletin has been elaborated from data of the Design Change No. ZKB D. MAN-HOURS Supposed Man-hours: Check: 0.25 M-hours Replacement: 2.00 M-hours E. MATERIAL - AVAILABILITY 1. New Equipment 2. Installation Parts To be delivered by the Aircraft Industries, a.s., Kunovice, Czech Republic against order. 3. Costs To be covered by the operator. F. SPECIAL TOOLS Page: 2 L-420/020a

3 G. WEIGHT AND BALANCE Influence of the replacement on an airplane weight and balance is negligible. H. USED DOCUMENTATION 1. Drawings: B N Windshield Wiper 2. Maintenance Manual, Chap.: Airframe Repair Manual, Chap.: I. AMENDED DOCUMENTATION Not affected. 2. INSTRUCTIONS FOR IMPLEMENTATION A. CHECK Remove windshield wiper arms according to the MM, chap , page 401, points 1.E. (2), (3). Check a diameter and height of clinched heads of both dowels with a slide gauge see Fig. 1. Permissible criteria: Fig. 1 Windshield wiper arm checked dowels o Diameter of a clinched head is minimally 5.5 mm for each of all four heads. o Height of a clinched head is minimally 0.7 mm for each of all four heads. If the permissible criteria are met, make a record into Airplane Logbook according to the part 4. of this bulletin. If the permissible criteria are not met, replace appropriate or both dowels by new pins according to part 2.B. of this bulletin. New pins can be ordered from airplane manufacturer Aircraft Industries, a.s., Kunovice, Czech Republic see material of part 3.A. of this bulletin. Install windshield wiper arms according to the MM, chap , page 401, points 2.E. (2), (3). L-420/020a Page: 3

4 B. REPLACEMENT 1. Preparatory Work Remove windshield wiper arms according to the MM, chap , page 401, points 1.E. (2), (3). 2. Dismounting Drill out a defective dowel/s. During drilling out a dowel follow instructions stated in the ARM, chap , Riveted joints repair - rivets replacement. 3. Mounting NOTE If only the dowel No. 2 is defective (see Fig. 1), it is recommended to replace both dowels by reason of a too strong spring. Mounting of both pins: Insert a new pin into the hole after drilled out dowel (the pin No. 2 first, see Fig. 1) according to the Dwg. No. B N. Verify free rotation of jointed parts. Use material pos. 1 of part 3.A. of this bulletin. Clinch the pin carefully by means of a centre punch (point angle cca 120 ) and complete the head by means of a hammer. No cracks must be on the clinched head. Mounting of the pin No. 1 (see Fig. 1): Attach a rod 10 mm in a vice and put the splined hole of the wiper arm onto the rod. Be careful not to remove a blind from the hole. Pull the wiper arm as far as the holes for the pin No. 1 are aligned. Insert the pin into the hole acc. to the Dwg. No. B N. Verify free rotation of jointed parts. Use material pos. 1 of part 3.A. of this bulletin. Clinch the pin carefully by means of a centre punch (point angle cca 120 ) and complete the head by means of a hammer. No cracks must be on the clinched head. Check dimensions of newly clinched head/s: o Diameter of a clinched head is minimally o Height of a clinched head is minimally 4. Tests Ground Tests 6.0 mm 1.0 mm Check of the windshield wiper function will be carried out within the scope of finishing works at part 2.B.5. of this bulletin. Flight Tests Page: 4 L-420/020a

5 5. Finishing Work Repair damaged paintings according to the MM, chap If the blind of the wiper arm splined hole has been removed, glue it with ARALDITE 2014, LOCTITE HYSOL 9489 or equivalent adhesive. Install windshield wiper arms according to the MM, chap , page 401, points 2.E. (2), (3) and (5). 3. NECESSARY MATERIAL A. INSTALLATION PARTS DELIVERED BY THE AIRPLANE MANUFACTURER Pos AI Identifier Name Pcs/acft 1 B N Pin 1 to 4 4. RECORD IN THE AIRPLANE LOGBOOK Check of windshield wipers dowels has been performed in accordance with Mandatory Bulletin L-420/020a. Found status: Dimensions of all four clinched heads meet permissible criteria the airplane is released into operation. or Any dimension/s of one or all clinched head/s does/do not meet permissible criteria defective dowel/s must be replaced in accordance with this bulletin within 30 calendar days. Date:... Performed:... (legible signature of verification engineer) Elaborated: Ing. Kamil Pergl... Checked: Ing. Pavel Ulrich... L-420/020a Page: 5