Figure 2-19.—Combustion liner dome band and plate cracks.Cracking (fig. 2-19) in the dome band area occursat relatively low operating time. Record the number ofcracks and their relationship to one another. Indicate ifthese cracks are parallel, T-shaped, circumferential orangled to connect and separate part of the band, and soforth.All the missing metal areas or burn-throughs (fig.2-20) must be recorded. For the dome bands, estimatethe magnitude by the number or partial/circumferentialspan of the dimples and axially by percent of span of theband overhang to the trumpet. Record the trumpet areasof burn-away and burn-through of the dome platearound the swirl cups. Burn-through in the combustordome will reduce cooling flow to the HP turbine vanes.Monitor the HP turbine vane condition as burn-throughprogresses.Igniter Tubes and Ferrules.— Inspect the twoigniter locations (fig. 2-21) for the condition of the weldat the cutaway of the trumpet and the dome band. Theferrules are visible from these ports. Record thecondition for evidence of cracking, 10SS of ferrule metal,or both. Cracking from the igniter tube aft to the paneloverhang is common.Figure 2-20.—Combustion liner dome bums and missingmetal.2-16
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