KC-46 air-to-air refueling tankers for the Air Force sit outside Boeing’s Everett Modification Center (EMC) at the south end of Paine Field, Friday, April 23, 2021. The EMC is where Boeing installs the refueling and other military systems on its 767 commercial airframe to complete the KC-46 tankers. (Ellen M. Banner, The Seattle Times/TNS)
SEATTLE (Tribune News Service) — Boeing is suffering a new rash of airplane problems.
A supplier’s manufacturing quality mistake has prompted Boeing to delay deliveries of 767 freighter aircraft and 767-based KC-46 refueling tankers for the U.S. Air Force, the company confirmed Tuesday.
Boeing is investigating the extent of the problem to determine which aircraft will need a lengthy fix.
Separately, inadequate tracking of the software used to customize cockpit displays for each airline is causing delays to lessors who need to switch delivery from the airline that originally ordered the jets to a different one.
These fresh problems follow on the heels of a renewed halt to 787 Dreamliner deliveries last month after discovering an error in the structural analysis of the jet’s forward pressure bulkhead conducted by supplier Spirit AeroSystems during the certification of a 787 model years earlier. Deliveries of the 787 have not resumed.
And so far this year, Boeing has not delivered a single 767 freighter or tanker because of this new problem: the interior of some center fuel tanks had not been properly cleaned nor the primer paint adhesion tested before the tanks were shipped to Boeing.
This leaves open the possibility that the primer could flake off inside the tank and clog fuel filters that feed the plane’s engines.
This news was first reported late Monday by online aviation trade journal The Air Current.
In addition to undelivered jets, the planes affected also include some cargo planes and Air Force tankers already in service, Boeing said.
The supplier of the center fuel tank, Triumph Aerostructures — now a unit of French aerospace conglomerate Daher — disclosed to Boeing that the proper cleaning and painting process had not been followed for some of the fuel tank interiors.
Boeing then notified the Pentagon’s Defense Contract Management Agency on January 17 of the paint primer adhesion issue on the tanker aircraft.
Monitoring for potential safety issues
Despite the potential for flaking primer to obstruct the fuel flow, Boeing said that “our engineering analysis to date is that the issue is not an immediate safety of flight concern.”
The Air Force reiterated that view, stating that “initial assessment” has not identified any immediate safety risk to the KC-46 tanker fleet.
Air Force spokesperson Alli Stormer said in an email that engine fuel filters on the KC-46 tankers are inspected and changed every two years during scheduled maintenance, and that 52 such checks have so far been performed on in-service tankers “with no findings of contamination, which would be a primary indication of this primer issue.”
In addition, Stormer said, every KC-46 tanker is equipped with a fuel filter pressure monitoring system that displays a message to the pilot if the pressure across the fuel pump and filter exceeds allowable levels, which would be another indication of a blocked filter.
“The investigation is ongoing, with the USAF monitoring the issue and paying close attention” to those indicators, Stormer wrote.
“Full root cause analysis and corrective action are still in work,” she added. “The USAF is still assessing any potential impacts from possible delayed deliveries.”
Asked about the potential for contamination to be passed from the fuel tank of a KC-46 to an aircraft receiving fuel from it, Stormer wrote that because “there have been no documented instances of fuel contamination” from this primer issue, the Air Force is not requiring inspections of refueling receiver aircraft.
The FAA in a statement said the agency “is aware of the issue and is working to ensure Boeing addresses it.”
Painstaking fix
For the affected planes, Boeing said its mechanics in the factory will have to defuel the tanks, then inspect, clean and apply new primer inside — a painstaking and slow job.
“We are continuing to work through our process with our supplier, regulator and customers to resolve the issue and will deliver airplanes as we complete rework,” Boeing said.
During the pandemic, the boom in the air-cargo market gave the 767 program new life, even though no passenger versions of the jet have been produced for a decade.
Boeing is currently building three 767s per month in Everett. Last year, it delivered 33 of the jets, 18 of which were freighter models and 15 Air Force tanker airframes.
Despite the lack of any deliveries so far this year, Boeing insisted Tuesday that “we are not changing our overall delivery plans for the year.”
A spokesperson for 767 freighter customer UPS said via email that the cargo carrier is “working collaboratively with Boeing on a quality control issue on one aircraft, however it is not having any material impact on delivery.”
And a spokesperson for FedEx said that carrier is “aware of the issue and working with Boeing ... and there has been no impact on our ability to operate safely and serve our customers.”
A new software glitch
The other new problem — first reported Monday by the online aviation trade site Leeham.net in conjunction with trade magazine Airfinance Journal — affects mostly the 737 MAX.
The issue arises when software installed on the airplanes that is customized for each airline must be reconfigured for a new customer after delivery.
A significant number of the MAXs that were grounded in long-term storage after the second MAX crash in 2019 had to be re-marketed to new airlines after the original customer canceled its order.
If an aircraft lessor takes delivery from Boeing and then delivers the leased plane to a different airline than originally intended, the switch process includes using certain software to customize the cockpit instrument displays.
For example, the new airline might want metric units displayed instead of U.S. units. Or it might want a different color that’s standard for its fleet on part of the display.
This software doesn’t affect the operation of the airplane; it just allows an airline to select from various options so as to set up the cockpit instrumentation visually the way it wants.
“This is not an airplane issue and addressing this does not involve rewriting software for Boeing airplanes,” the jet maker said Tuesday. “It has been determined to not be an airplane safety issue.”
However, Boeing’s tracking and documentation of the options chosen and installed for each airplane in the factory is lacking, with the result that reconfiguring the customization can be delayed.
Leeham.net reported that new 737 MAXs ordered by Miami-based lessor 777 Partners for lease to Canada’s Flair Airlines instead were sold upon delivery to a different lessor for lease to another airline.
Boeing initially told the new lessor that the cockpit instrument customization software could be loaded into the plane’s electronic boxes and reconfigured within two months.
The Leeham.net report said Boeing subsequently informed the lessor that a lack of documentation would delay the reconfiguration process until January 2024.
Boeing said Tuesday that “this work is primarily related to post-delivery reconfiguration” with no impact on its deliveries from the Boeing assembly plant and “no impact to our delivery outlook.”
“It is largely a process compliance [documentation] activity that we have been closing out for several months,” Boeing said.
The FAA declined to comment on this software problem.
Jefferies financial analyst Sheila Kahyaoglu in a note to investors Tuesday wrote that “the potential impact could be delays for 30-40 aircraft,” apparently referring to delays that some lessors will endure before they can deliver the jets to their airline customers.
Responding to that note, Boeing reiterated that “our delivery guidance has not changed.”
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