My favorite recommendation:
Quote:
The aircraft manufacturer evaluate the need for providing guidance on
how to perform fuel leak check with the engines operated at unequal
thrust. [TSIB Recommendation RA-2017-023]
Dinger, there already is a system along that line (not sure if it's been fully implemented through the Boeing fleet yet but it was an FAA mandate). Basically, it compares fuel used (according to the engine fuel flow indications) with fuel remaining (according to FQIS). If it differs significantly it sets an EICAS message. Although it wouldn't catch a leak downstream of the fuel flow meter, it would help indicate a fuel leak of this type (fuel/oil heat exchanger). However the problem is neither the FQIS or the fuel flow meter systems are super accurate, so the limits are set rather loose to avoid nuisance alerts.