Good news for the 777-9 and 737-MAX

The giant 777-9, which is looking increasingly like the swan song for very large aircraft, finally had some good news, as General Electric received the FAA’s certification for the massive GE9X engine.

The engine is actually wider than a 737 or an A320 fuselage, and is the largest high-bypass fan ever conceived. A total of ten of the engines have been delivered to Boeing, eight for use on aircraft and two spares.

GE and Boeing flew 5,000 hours and 8,000 cycles, including flights on GE’s 744 flying testbed.

Now that the engine has received FAR Part 33 certification, GE will begin shipping units to airframes already constructed for customers, the first of which will be installed during late Q4 and early Q1 202.

Ground testing for ETOPS (extended twin engine operations) approval are still being conducted, and GE is well underway with preparing service operations training and manuals.

The engine is immense, with a 134″ (3.404 metres) fan blades, of which it has sixteen. It has a pressure of 60:1, the highest of any civil aircraft engine and uses a number of ceramic matrix composite parts, including those for the first-stage shroud and first and second-stage nozzles on the high-pressure turbine, and the inner and outer linings of the combustion chamber

EASA has confirmed it expects to re-authorise the 737MAX in November, with a return to service being fully permitted by years end. The FAA is expected to do the same, but an actual operational use of the aircraft will depend on individual national authorities and the airlines themselves.

EASA’s requirements go beyond what the FAA laid out in a draft mandate issued in August by adding a third AOA (angle of attack) sensor to the model. The synthetic sensor, which will provide more data redundancy for systems including the MCAS, will be introduced on the 737-10 and retrofitted on other models, including those in service.

Among FAA-mandated changes Boeing made to the MCAS is ensuring the two sensors compare readings and are within 5.5 deg. before triggering nose-down stabiliser inputs. The third sensor required by EASA will independently calculate a reading to supplement the two existing ones. In the meantime, EASA will approve operational protocols that allow pilots to safely manage a scenario where the two sensors disagree significantly. 

The only outstanding issue is EASA’s push for Boeing to provide pilots with a way to disable stick-shaker stall warnings, a problem that several other stakeholders have also asked be resolved, including pilots.

Another issue has been runway trim, and emergency protocols.

Notably, EASA also added that it was looking closely and with added vigilance at certification for the 777-9.