Weak springs in a B-2 Spirit stealth bomber led to the collapse of its left touchdown gear and a skid off the runway because it was touching down at Whiteman Air Power Base, Missouri, in September, an Air Power investigation discovered.
The 2 key springs within the bomber’s collapsed left foremost touchdown gear didn’t present sufficient strain to maintain it in its locked place, in keeping with an accident investigation report that Air Power International Strike Command launched to the general public Thursday.
The failure of those springs was the first reason behind the mishap, in keeping with the Jan. 12 report from the investigation board, headed by Col. Robert Cocke.
These springs hadn’t been changed in not less than a decade — and maybe by no means, the report stated. In 2018, the Air Power modified the B-2′s upkeep procedures to require these springs to get replaced each 9 years as a part of repeatedly scheduled depot upkeep. However this bomber final went into the depot in 2014, earlier than that process had been modified. No proof might be discovered displaying these springs had ever been changed, investigators stated.
An Air Power Analysis Laboratory evaluation of the 2 springs within the left touchdown gear discovered they have been outdoors the tolerance stage and producing about 11% much less rigidity than they have been designed to offer.
A fast lack of hydraulic fluid brought on by a small steel fatigue crack in a hydraulic coupling unit additionally saved the bomber from deploying its touchdown gear usually and was decided to have considerably contributed to the mishap.
The B-2′s left touchdown gear collapsed inside seconds of touching down. Its left wing hit and dragged alongside the runway because the bomber veered onto the grassy space east of the runway. Each pilots have been unhurt and have been capable of shut down and exit the bomber. No hearth broke out.
However the B-2, dubbed the Spirit of Georgia and assigned to the 393rd Bomb Squadron of the 509th Bomb Wing at Whiteman, suffered important harm to parts together with its left foremost touchdown gear, its door, the pores and skin underneath its left wing, left decrease wingtip gentle and left decrease rudder.
Restore prices have been estimated to be not less than $10.1 million within the report, however the ultimate price may find yourself being a lot greater: The investigation stated engineers have to take a more in-depth search for inside structural harm to its left wing.
The publicly launched report doesn’t get particular concerning the extent of the harm to the bomber’s extremely delicate, low-observable stealth coating.
The Air Power has 20 B-2s in its fleet, which price about $1.1 billion apiece. The Spirit of Georgia was delivered to Whiteman in December 1995.
This B-2 was on its third coaching sortie of the day when it tried to land shortly after midnight on Sept. 14, and there have been no indicators of any hydraulic issues through the first two flights. Whereas on strategy, the crew tried to increase its touchdown gear usually. However virtually instantly, a warning gentle warning of a hydraulic downside lit up, and the pilots declared an in-flight emergency.
The bomber’s proper touchdown gear had skilled a failure of its high-pressure CryoFit coupling, which brought about all 21 gallons of hydraulic fluid in a single system to empty out inside a minute. The bomber mechanically switched to a second hydraulic system, and it shortly misplaced practically all of its fluid as nicely. The lack of that fluid additionally meant a hydraulic lock hyperlink actuator was not working and couldn’t assist the springs hold the touchdown gear locked in place.
The pilots began an emergency touchdown gear extension to verify all touchdown gear have been down and locked, which makes use of saved strain to knock the touchdown gear into place, after which gravity and airflow to lock it into place with the mechanical lock hyperlink system.
The bomber touched down and briefly bounced, although the investigation discovered it wasn’t a tough touchdown, after which touched down a second time. Then, with out sufficient spring strain to maintain the left touchdown gear locked in place, it started to break down partially again into its wheel nicely.
The left touchdown gear door, which remained open through the emergency touchdown, touched the runway and dragged for about 750 ft earlier than it ripped off, ripping open the pores and skin on the underside of the wing and exposing its inside construction.
The crew struggled to maintain the bomber taking place the middle of the runway, nevertheless it dipped to the left, leaving scrape marks from its left decrease rudder and wingtip alongside the runway’s edge. Just a few seconds later, that rudder additionally was torn off and slid throughout the runway.
The bomber’s teacher pilot tried to steer it laborious to the appropriate and brake to maintain it on target. However the appropriate and left touchdown gear wheels locked up and the bomber started to veer laborious to the left. It left the runway’s japanese edge and got here to a cease about 140 ft into the grassy infield.
The report stated each pilots have been present and certified within the B-2, and that human components weren’t a reason behind the mishap.
It stays unclear what, if any, upkeep procedures could also be modified on account of this mishap and the investigation that adopted.
Stephen Losey is the air warfare reporter at Protection News. He beforehand reported for Army.com, overlaying the Pentagon, particular operations and air warfare. Earlier than that, he lined U.S. Air Power management, personnel and operations for Air Power Instances.
