56-19-02 HAMILTON STANDARD: Applies to All 2J17 Steel Propeller Blades Installed on Boeing 377 Aircraft.
Compliance required as specified herein.
This note consolidates all items of AD notes and revisions issued on the subject propeller blades prior to August 1, 1956. Only those items that are still in effect are included.
I. The inspection and maintenance procedures given in Hamilton Standard Service Bulletin No. 302, except as modified by this AD must be accomplished on a continuing basis.
II. No external deicers shall be used on the exposed metal portions of the blade.
III. Blades of the "stiffener type" shall not be used.
IV. The following r.p.m. restrictions shall be included in the aircraft placard:
(A) For aircraft having zinc-plated blades:
(1) "Avoid ground running under static conditions above 2,600 r.p.m."
(2) "Avoid continuous ground operation between 1,400 and 2,000 r.p.m."
(3) "Avoid continuous operation in flight below 1,750 r.p.m. except 1,400 r.p.m. may be used for level cruise but not for descent."
(B) For aircraft having nickel-plated blades:
(1) "Avoid ground running under static conditions above 2,500 r.p.m." This shall be accomplished by increasing the settings of the low pitch stops in the propeller hub.
(2) "Avoid continuous ground operation between 1,400 and 1,900 r.p.m."
(3) "Avoid continuous operation in flight below 1,750 r.p.m. except 1,400 r.p.m. may be used for level cruise but not for descent."
V. Propeller blades in service that have not been renovated or rebuilt by Hamilton Standard. Blade Serial Numbers below 649,400.
(A) Conduct hand magnetic inspection of entire blade at 400-500 hour intervals of operation.
(B) Blades on which corrosion was found and repaired within acceptable tolerances must not have these reworked areas covered with any material which would preclude discovery of a crack or other defect. Direct inspection, the use of hand magnetic inspection procedures or equivalent, must remain effective.
(C) Conduct hand magnetic inspection of garter area daily on blades on which corrosion was found and repaired. On blades on which no corrosion was found, conduct similar inspection at 65-hour intervals of operation.
(D) Conduct electrical leakage check in accordance with Section G-3 of Hamilton Standard Service Bulletin No. 302 at 120-hour intervals of operation for blades with Serial Numbers below 619,000 and 500-600 hour intervals for blades with Serial Numbers from 619,000 to 649,400.
(E) Conduct electrical resistance check in accordance with Section G-4 of Hamilton Standard Service Bulletin No. 302 as follows:
(1) Within 65 hours after each deicer circuit energization. (NOTE: When propeller deicing is used regularly over an extended period of time resistance checks may be conducted at 65-hour intervals of operation rather than after each use.) A means should be provided at the deicer circuit switches that will clearly indicate when a switch has been operated to energize the circuits. Maintenance procedures and instructions should be established to provide for the resistance check within the specified time whenever the indicator shows that the deicer circuits have been energized.
(2) At each composite service, not to exceed 200 hours.
VI. New propeller blades incorporating special treatment of unplated area and an 8- inch rubber sleeve in place of narrow garter previously used. These new blades can be identified by (1) presence of 8-inch sleeve in place of narrow garter, (2) Serial Numbers above 649,400, (3) model designation 2J17H3-8W change AE or later (zinc plate), 2J17Z3-8W change R or later (nickel plate), 2J17AG3-8W (zinc plate) or 2J17AH3-8W (nickel plate).
(A) At a maximum of 1,500 hours operation, remove the sleeve, and inspect the exposed area for corrosion, and the entire blade visually and hand or machine magnetically for other defects. If the blade satisfactorily passes inspection, a new sleeve shall be installed prior to further service. These inspections shall be repeated at intervals of 1,500 hours of operation maximum.
(B) Conduct electrical leakage check in accordance with Section G-3 of Hamilton Standard Service Bulletin No. 302 at the time of hand magnetic inspection specified in VI. (A).
(C) Conduct electrical resistance check in accordance with Section G-4 of Hamilton Standard Service Bulletin No. 302 as follows:
(1) Within 65 hours after each deicer circuit energization. (NOTE: When propeller deicing is used regularly over an extended period of time, resistance checks may be conducted at 65-hour intervals of operation rather than after each use.) A means should be provided at the deicer circuit switches that will clearly indicate when a switch has been operated to energize the circuits. Maintenance procedures and instructions should be established to provide for resistance check within the specified time whenever the indicator shows that the deicer circuits have been energized.
(2) At each composite service, not to exceed 200 hours.
VII. Factory renovated propeller blades incorporating special treatment of unplated area and an 8-inch rubber sleeve in place of narrow garter previously used. These blades can be identified by (1) presence of 8-inch sleeve in place of narrow garter, (2) Serial Numbers between 645,300 and 649,400, (3) model designation 2J17H3-8W prior to change AE (zinc plate), or 2J27Z3-8W prior to change R (nickel plate).
(A) At a maximum of 1,500 hours of operation remove the sleeve, and inspect the exposed area for corrosion, and the entire blade visually and hand or machine magnetically for other defects. If the blade satisfactorily passes inspection a new sleeve shall be installed prior to further service. These inspections shall be repeated at intervals of 1,500 hours of operation maximum.
(B) Conduct electrical leakage check in accordance with Section G-3 of Hamilton Standard Service Bulletin No. 302 at the time of hand magnetic inspection specified in VII.(A).
(C) Conduct electrical resistance check in accordance with Section G-4 of Hamilton Standard Service Bulletin No. 302 as follows:
(1) Within 65 hours after each deicer circuit energization. (NOTE: When propeller deicing is used regularly over an extended period of time, resistance checks may be conducted at 65-hour intervals of operation rather than after each use.) A means should be provided at the deicer circuit switches that will clearly indicate when a switch has been operated to energize the circuits. Maintenance procedures and instructions should be established to provide for the resistance check within the specified time whenever the indicator shows that the deicer circuits have been energized.
(2) At each composite service, not to exceed 200 hours.
VIII. Check strength of hand magnets for conformance withHamilton Standard Service Bulletin No. 302 or equivalent before each use, or daily when in continued use.
IX. To supplement the above precautions, while in flight continue to monitor the vibration indicator at least hourly for any indication of progressive unbalance.
X. While in flight continue to monitor the propeller deicer current load meter for any indication of deicer heater resistance change.
This supersedes AD 55-21-01.