Mr Point,
Any maintenance policy for the SCP and other similar ducts would have concentrated on mitigation against duct failure due to internal corrosion, because that was what caused that incident. No policy would have been implemented to specifically reduce the temperature of the air inside or outside the duct, because the air temperature at that location is what it is, due to operation of the system. Anyway, lets say that they had, co-incidentally, decided to fit new and better insulation around the duct. It still would not have stopped the leaking fuel (from wherever it came) from coming into contact with the either the hot pipe directly or the insulation. Here is something that you probably don't know (its not in the BOI report): The source of the hot air in the SCP duct is the exit of the HP compressor, known as P3/T3. At sea level, at 100% power, T3 on an engine test bed has been recorded at 500 degrees. The BOI conducted ground tests on installed engines (as per the report) to establish the likely temperature of the SCP duct during the AAR sequence on 230. Due to a lack of ram air on the ground, the SCP pre-cooler overheated with only 90% power and the duct temp at the SCP elbow was recorded at 400 degrees at that time. At 90% power, the engine is just coming into its designed power range, so Ts and Ps, although very high, are far from maximum. This concurs with the previously mentioned test bed figures. At 20,000 ft, (OAT -25 ish) during the AAR sequence, the record shows that the engines were almost at max power, so T3 would have been much closer to 500 degrees, with a reduction factor to account for the lower OAT. Then we can reduce the temperature on the outside of the brand new insulation and assume no gaps in it due to a clever way of having static insulation on a fixed pipe with a seemless connection to insulation on a bellows pipe. The existing insulation has been recorded to drop the temperature by 16 degrees, so we'll work on more than that, say 30 degrees. The bottom line is that the outside of any new insulation, with the engines close to max power, is still going to exceed 400 degrees, IMHO.
So, it would be incorrect to say that any new maintenance policy implemented as a result of 227's incident would have prevented the fire. I would agree that it might have done so, but that is not what you said at the outset. There were definitely failures in other areas of maintenance policy and, if you want to bang a drum, have a look at the BOI's comments about the NSC and fuel coupling failure trend analysis. These 2 failures are at the heart of the matter.
Regards
Ed Sett