SERVICE BULLETIN 25-53-03

Full document text

1 de 4 SERVICE BULLETIN Nº 25/53/03 Rev: Original Date: May 10/06 COMPLIANCE: MANDATORY THE TECHNICAL CONTENTS OF THIS SERVICE BULLETIN HAVE BEEN APPROVED BY THE D.N.A. SCOPE : REAR AND FORWARD SUPPORTS OF BOTH HORIZONTAL STABILIZER MODIFICATION. BACKGROUND: It have been found on several of the affected airplanes some severe corrosion and cracks in both supports. The probable cause for those failures is the accumulation of steam or application products vapors. The Dirección Nacional de Aeronavegabilidad through the Dirección de Aviación General issued the ADVERTENCIA: 035/DAG, dated 29 Jun 2004 advising to the aeronautical community about this risk situation. The affected airplanes were those with an accumulated time in service of 2000 flight hours (F.H.) average, approximately. APLICABILITY: Affected models: PIPER “Pawnee” PA 25; PA 25-235 y PA 25-260; CHINCUL “Pawnee” PA 25; PA 25-235 y PA 25-260; LAVIA “Puelche” PA 25-235 y PA 25-260. Serial numbers: All serial numbers of the affected airplanes operating in the Republic of Argentina Register or outside the country. Exceptions are made for the following S/N LA-260-06008 and up which are in factory modified. Activity requiring applicability: Airplanes with 1500 or more F.H. TIME FOR ACCOMPLISHMENT: INITIAL ACTION: Next 50 F.H. for the first inspections. REPETITIVE ACTION: Every 100 F.H. DEFINITE ACTION: First 1000 F.H. inspection, after the issuance date of this Service Bulletin. ACTIONS: INITIAL: When performing the next 50 F.H. inspection add a detailed visual inspection to check the condition of both, rear and forward supports in the two sides of the horizontal stabilizers, The check is pointed out to detect cracks, dust, corrosion or other kind of anomalies in the structural support tubes. The inspection must look for the evidence of irregularities in the painting of the area, pieces of metal and/or the presence of dust in the inspected tubes. Additionally take both stabilizers by their main spars close to the root and shake them up and down to determine if there is some excessive play as well as unusual noises. Hangar N° 1 Aeropuerto “El Plumerillo” sur Las Heras- Mendoza- Argentina - CP 5541 Tel/Fax: +54-261-4489198 EMAIL: laviasa@hotmail.com 2 de 4 LATINOAMERICANA DE AVIACIÓN S. B. Nº 25/53/03 Rev: Original Date: May, 10/06 Both conditions can indicate the presence of some failure. The excess of flexibility in the trusses when loaded in the central point can indicate supporting tubes failure, as well as lack of trusses tension. This task may be performed during the first 50 H.V. inspection, and the needed elements are adequate light and a 10 X magnifying glass. After performing the inspection make an entry in aircraft log book. REPETITIVE: Repeat the operation described in INITIAL ACTION, every 100 F.H. inspection, including the corresponding entry in the log book. NOTES: 1.- This actions must be repeated up to the DEFINITIVE ACTION application. 2.- If some irregularities as those pointed out in the upper part of this S.B. are detected, the repair shop performing the 50 F.H. inspection must go to a deeper inspection including disassembling and check both supports. See Figure 1 to locate possible damaged areas in the supports. 3.- If some of the anomalies described in NOTE 2 are detected DEFINITIVE ACTION must be apply. DEFINITIVE: Disassembly both stabilizer surfaces (See Manual de Mantenimiento PUELCHE for details related to this disassembly). Remove fabric in the areas of both supports) , to gain access, this remotion must provide enough room to operate adequately. Once you get the corresponding room, proceed to remove both support and destroy them, use an adequate grinder to eliminate the remaining pieces of both supports. After performing the previous operation, install new parts of Kit ( Forward support P/N K- 002 D, and rear support P/N K-002 T), taking into account the correct alignment of the supporting tubes. Weld both supports by using a T.I.G. machine and perform a continuous weld bead all along the contact area. After completing the welding process verify again the correct position and alignment of the supports. Clean the area and protect with zinc chromate painting. Restore the removed fabric covering using a methodology and applicable techniques pointed out in the Advisory Circular FAA AC 43.13-1A, Section 3 or in CAM 18, Section 18.606. Protect and reinstall all removed elements. Perform the tensing of the horizontal stabilizers truss (Refer to Manual de Mantenimiento of the aircraft). Verify alignment of the horizontal stabilizers and check for free movements. This task must be performed by an Aeronautical Repair Shop with the proper qualification by the civil aviation authority to do the job. EXECUTION TIME: 10 (ten) working hours, approximately. ELAPSED TIME: 1 (one) day. MATERIALS: Kit Nº LA K-002, composed by: 1.- Forward support P/N K-002 D. 2.- Rear support P/N K-002 T. 3.-Tool to locate and mounting N° LA-60207-H: This tool will be supplied with adequate instructions for its use. 3 de 4 LATINOAMERICANA DE AVIACIÓN S B Nº 25/53/03 Rev: Original Date: 10/05/06 AVAILABILITY OF PARTS: Immediate, previous consulting to the manufacturer. WORKMANSHIP: Two mechanics, including a properly qualified welder. TOOLING: Standard. WEIGHT AND BALANCE: Non significantly affected. CONSULTING: Tel/Fax 0054-261-4489198. E-mail: “laviasa@speedy.com.ar” 4 de 4 LATINOAMERICANA DE AVIACIÓN S. B. Nº 25/53/03 Rev: Original Date: 10/05/06 FIGURE 1 Typical cracked Tubing right side Typical cracked Tubing left side Horizontal stabilizer Rear attachment Horizontal stabilizer Foward attachment