DOCUMENT TYPE AND REF No. TECHNICAL NEWS SHEET CT (MOTH) NO.25
 

TITLE:

EXAMINATION OF OIL JET AND FILTER TO MAGNETO SPIRAL GEAR.

CLASSIFICATION RECOMMENDED

GYPSY MAJOR ENGINE - IN USE AND IN STORE.

This TNS is applicable to all Moth Series Aircraft powered by Gypsy Major Engines.

Cases have been found where the Magneto Driving Spiral Gear has failed due to lack of lubrication caused by a blockage in the Oil Jet Pipe and Oil Jet Pipe Filter.

Subsequent to these incidents being reported. H and S Aviation issued a TNS G. No.80 dated 15.3.93 to inform operators of the condition, and detailed a recommended inspection procedure.

British Aerospace fully endorse the H and S Aviation TNS No.80 inspections which are now contained within this TNS CT (MOTH) No.25 Page 2) and STRONGLY RECOMMEND that operators carry them out within 14 days of receipt of this TNS CT (MOTH) No.25 and thereafter at each annual check

DOCUMENT TYPE AND REF No. TECHNICAL NEWS SHEET CT (MOTH) N0.25

H+S GIPSY AERO ENGINES

This T.N.S. is issued to alert operators of an incident with a Gipsy Major Engine in which the oil feed to the Magneto Driving Spiral Gear was interrupted due to the oil jet pipe filter and oil jet being blocked. The subsequent lack of lubrication caused the driving gear to fail with a resulting loss of ignition, resulting in an unscheduled landing.

ACTION REQUIRED (All references are to the G.M.1-10 Parts Catalogue).

Ensure aircraft is safe for servicing.

Gain access to the Auto Kleen Pressure Filter Assembly (item 13, page 79) and oil jet (item 40, page 102).

Examine the oil jet pipe filter (Pt. No. 1308-71) (item 4, page 79) for debris. Using a suitable spanner remove and examine the oil jet (Pt. No. 1306-66). If the filter is contaminated or the jet is blocked ,clean using Avgas and dry using compressed air.

If the jet is found blocked, the Magneto drive gear train must be examined for excessive wear in accordance with the Overhaul Manual.

Refit oil jet pipe filter using new joint washer (Pt. No. 1306-68) (item 3 page 79) and new tab washer (Pt. No. 1306-69B) (Item 5, page 79).

Refit oil jet using new tab washer (Pt. No. 1306-69B) Item 41, page 103).

Carry out ground run and check for oil leaks.

This examination to be carried out within 14 days of receipt of this instruction, and thereafter every Aircraft Annual Check.

The contents, and classification of this T.N.S. are approved by the C.A.A.

PAGE: 2 OF 2 PAGES

DATE 1st OCTOBER 1993