Boeing will need to complete more 777-9 analysis and assuage regulatory concerns, including those related to design changes, prior to the Federal Aviation Administration agreeing the jet is on track to meet certification requirements.

That is according to a recently-released letter in which the FAA outlines concerns and says it is unlikely to issue the 777-9’s amended type certificate until mid- to late-2023. 

The given timeline does not mean a fresh delay for the 777-9 because, in January, Boeing pushed back its first planned 777-9 delivery until late 2023.

The letter, dated 13 May, highlights changes Boeing is making to the 777-9 and mentions lack of clarity about progress toward certification in Europe. It says the FAA needs more information – including about a major software architecture called the “Common Core System” (CCS) – before considering the 777-9 to be on track to certification.

777X test ac #2 first flight 043020-2

Source: Boeing

Boeing’s second flight-test 777-9

Specifically, the FAA’s letter addresses the state of the 777-9’s “Type Inspection Authorisation” (TIA) – a milestone issued by the FAA when it determines that an aircraft “is expected to meet” certification requirements.

“The FAA and Boeing have been discussing the TIA readiness of the Boeing Model 777-9 in numerous meetings over the past nine months,” says the letter. “Based on our assessment, the FAA considers that the aircraft is not yet ready for TIA, even if it is a phased TIA of limited scope with a small number of certification flight test plans proposed.”

The letter was sent from the FAA’s Aviation Safety unit to Boeing staffer Tom Galantowicz, who administers the Chicago airframer’s 777-9 certification effort. The Seattle Times reported about the letter on 27 June.

“The technical data required for type certification has not reached a point where it appears the aircraft type design is mature and can be expected to meet the applicable regulations,” the letter adds. “The Model 777-9 amended type certification date is realistically going to be mid- to late-2023.”

Asked to comment, the FAA says it “will not approve any aircraft unless it meets our safety and certification standards”.

Boeing “remains fully focused on safety as our highest priority throughout 777X development”, the company says.

“As we subject the airplane to a comprehensive test programme to demonstrate its safety and reliability, we are working through a rigorous development process to ensure we meet all applicable requirements,” it adds. “We continue to communicate transparently with the FAA and other global regulators about 777-9 certification.”

Boeing is working to certificate the 777-9 amid heightened regulatory scrutiny following the 737 Max disaster.

The FAA’s letter says Boeing plans an “upcoming major software update” to the 777-9 that is intended to address “many” items, including a “fix for the un-commanded pitch event that occurred on December 8, 2020”.

“After the un-commanded pitch event, the FAA is yet to see how Boeing fully implements all the corrective actions identified by the root cause investigation,” the letter says.

The FAA expects Boeing will complete a comprehensive review “and implement a robust process, so similar escape will not happen in the future and [so] this is not a systemic issue”.


Details about that event were not disclosed. The 777-9 made its maiden flight in January 2020.

Much of the letter’s focus rests on the 777-9’s CCS, which the letter says fails to meet “readiness requirements”. Boeing does not provide details. But in 2014 GE Aviation said it had been chosen by Boeing to provide the 777X’s CCS.

GE Aviation did not respond to a request for comment.

“The CCS is a very complex and critical avionics system,” the FAA’s letter says. “It is an integrated modular avionics architecture that provides a set of shared computing, networking and input/output resources.”

The CCS system on the 777-9 marks a “significant change from the baseline 777-300ER,” the letter adds.

It cites “lack of sufficient data” related to the CCS, and “lack of availability of [a] preliminary safety assessment for the FAA to review”. The agency cannot yet confirm the CCS “is mature and will provide only uncorrupted data”.

It notes that Boeing’s proposed modifications to the 777-9’s design include “firmware and hardware changes to the actuator controls electrics of the flight control system”. Boeing chief executive David Calhoun disclosed in January that Boeing was making those types of design changes.

The FAA still has “concern” about the modifications, and the European Union Aviation Safety Agency (EASA) “has not yet agreed on a way forward on the Model 777-9”, the letter says. “Boeing needs to ensure the changes do not introduce new, inadvertent failures.”

It adds that “design maturity is in question, as design changes are on-going and potentially significant”. The letter asks Boeing’s Organisation Designation Authorization office – the company’s self-certification unit – to “close these gaps” before requesting that the FAA issue the Type Inspection Authorization.

In early June, CEO Calhoun said Boeing remains “confident” that the 777-9 will be certificated in the fourth quarter of 2023.

He said Boeing’s timeline incorporates lessons from the 737 Max’s re-certification and “the architectural preferences that both the FAA and the EASA has embedded in their regulations”.

“We don’t have like a load of technical glitches and we don’t have a battery issue,” Calhoun added. “We don’t have that kind of stuff.”