ABOVE: B-17G Yankee Lady is currently grounded due to issues with wing mounts

The FAA is expected to issue a mandatory Airworthiness Directive (AD) within the coming weeks to address Boeing B-17 wing mounts.

Pre-empting a directive that could ground all B-17s, the Michigan-based Yankee Air Museum temporarily grounded B-17G Yankee Lady on 13 April 2023. One of only three B-17s left flying in the United States (along with sister aircraft Ye Olde Pub of Erickson Aircraft Collection and Sentimental Journey of CAF Arizona Wing), Yankee Lady is the youngest surviving Flying Fortress in the world.

Although an earlier Facebook post from the Yankee Air Museum noted that the grounding was due to wing spar issues – noting that similar problems had been identified during inspections of other B-17s – a statement from Hangar Thirteen on 17 April confirmed that her grounding referred to the wing mounts rather than the spar itself.

However, Hangar Thirteen – who are restoring B-17F Lucky Thirteen – also highlighted the problem posed by B-17 wing spars, citing an earlier AD from November 2021 which “grounded many of the airworthy Forts due to the near impossibility of recreating the parts in question”. Each wing has four spars, each 25ft 4in long, and alongside the difficulties in finding a manufacturer “capable of reproducing these materials” come significant cost implications.

Clarifying that no spar issues have been found with Yankee Lady, Hangar Thirteen noted that “it was [their] hope that throwing some light on the subject might aid in fabricating new spar extrusions”; adding that “the aviation community needs a quality, economical means of recreating these pieces”.

Any upcoming AD may also affect Europe’s only airworthy Flying Fortress – the Sally B – which is based out of IWM Duxford and “continues to fly from there today as a memorial to the US servicemen who died whilst serving in Europe”.