Composites - shades of the Coment
Another issue is the 'Emergency Cut Here' marks on the fuselage. An axe bounces off !
Here is an interesting letter to the Aerospace magazine:-
Composites - shades of the Comet ?
"Reading Bill Read's article in the February issue. On the maintenance aspects of aircraft containing an ever increasing proportion of composite materials in their structure, has awakeneed a long felt concern that I have about these materials. Fuelled by the huge benefits that are there to be exploited in terms of higher structural efficiency over their metal equivalent, especially in these times of austerity and the need for ever lower seat mile costs, industry, driven by its customers, has embraced this new relatively unknown material and forged ahead to integrate it into the very heart of airframe manufacture. In this latest breed of airliners, tried and tested metals that are know completetly understood through the hard lessons from generations gone by, are increasingly becoming the exception rather than the norm.
We understand composites as manufactured and we are perfecting processes to manufacture ever more complex components and assemblies out of this new and challenging material. But it is not tolerant of damage, it is not easy to spot(the extent of) damage, it is not esy to repair, it is not easy to guarantee a repair. Consequently, the long term integrity of such repairs has to be questionable. We understand the science but I fear we don't understand its durability in a damage risk environment.
Back in the post war days, we thought we understood metals. The Comet was a frightening illustration of how little we did know. Speed, distance and comfort were then the driving forces. Chasing the current-day holy grail of minimal seat-mile costs could be a frightening analogy."
- John H Mangan CEng MRAeS