Summary
We propose to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) GE90 turbofan engines. This proposed AD was prompted by a report of an engine and airplane fire. This proposed AD would require replacing affected fuel/oil lube/servo coolers (``main heat exchangers'') with a part eligible for installation. We are proposing this AD to prevent failure of a main heat exchanger, which could result in an engine fire.