Interim report
released on loss of F-35B on HMS Queen Elizabeth
By Dave Allport
8th September 2022
An interim report
into the loss of UK F-35B Lightning II ZM152 ‘018’ on HMS Queen Elizabeth (R
08) on November 17, 2021, was published by the UK Ministry of Defence on
September 8.
 |
| Lockheed Martin F-35B Lightning II ZM152 ‘018’ operated by 617 ‘Dambusters’ Squadron on board HMS Queen Elizabeth on August 24, 2021. This was the aircraft which crashed on November 17, 2021 MOD Crown Copyright/LPhot Unaisi Luke |
As was widely
reported at the time, while being operated by the Royal Air Force’s 617
‘Dambusters’ Squadron and undertaking routine flying operations from the
carrier in the eastern Mediterranean Sea the aircraft crashed into
international waters, soon after take-off from the ship. The pilot ejected
using the aircraft’s Martin-Baker US16E ejector seat and was safely returned to
the carrier. This was the first loss of a UK F-35B. The report confirms
speculation at the time that an engine blank had accidentally been left in one
of the intakes, causing loss of power.
The Interim Report
by the Director General Defence Safety Authority, was completed on June 23,
2022, but not made public until September 8 and was as follows:
A Service Inquiry is
being undertaken investigating the accident involving F-35B ZM152 on HMS Queen
Elizabeth on November 17, 2021. This Interim Report contains facts which have
been determined up to the time of issue. It is published to inform the military
chain of command, aviation industry and the public of the general circumstances
of this accident and should be regarded as tentative and subject to alteration
or correction if additional evidence becomes available. The Service Inquiry is
still ongoing at this time; the full report will be published on completion.
All times are Local
(UTC + 2 hrs). While the investigation into the F-35B accident of Nov 17, 2021,
is ongoing, the SI Panel is now confident that the cause was not related to an
aircraft technical issue but was most likely caused by human, organisational
and procedural factors. On November 17, 2021, HMS Queen Elizabeth (QNLZ) was
operating in the eastern Mediterranean six months into her maiden Carrier
Strike Group deployment, Operation Fortis.
United States Marine
Corps F-35B aircraft had commenced flying operations at 0630hts and two UK
F-35Bs, from 617 Squadron (Sqn), were programmed to launch at 1145hrs. The lead
aircraft, ZM152 taxied to the runway for launch at 1137hrs. The aircraft
converted to short take-off mode and at the direction of the Captain of the
Flight Deck the pilot conducted engine run up checks, confirmed all engine
indications were normal, selected take-off power, 97% Engine Thrust Request
(ETR), and released the brakes.
The pilot reported
that the initial acceleration felt normal, but then decreased. On checking the
engine displays they discovered that the power was low, at 74% ETR. The pilot
then selected maximum (100% ETR) but the engine continued to deliver lower than
expected power. Due to the resulting low speed of ZM152, the pilot attempted to
abort the take-off but was unable to stop the aircraft before the end of the
ramp and ejected. The ejection was successful, the parachute deployed, and the
pilot landed on the flight deck suffering only minor injuries. The aircraft
impacted the sea and was seen to be afloat passing down the port side of the
ship before it subsequently sank.
ZM152 last flew on
November 13, 2021 and required no maintenance activity before the preparation
for its flight on November 17, 2021. During the day prior to the accident, QNLZ
transited through the Suez Canal on her homeward passage. As a security measure
for that passage all F-35Bs on the flight deck had Red Gear fitted. Red Gear,
which included engine intake blanks, was designed to protect from ingress of
foreign objects. That night, 617 Sqn engineering personnel serviced ZM152 to
prepare it for flight the following day.
ZM152’s servicing
was tasked to two engineers who started shift at 1930hrs. The first engineer
conducted their aspects of the servicing shortly after 2130hrs and was
completed no later than 2300hrs. After a mid-shift meal, the second engineer
started their work at 0030hrs. During the intervening period there was
thunderstorm activity around the ship. When the second engineer arrived at the
aircraft to conduct their part of the servicing and on all subsequent
inspections of the aircraft prior to flight, the intake blanks were not seen.
During their individual tasks, the engineers removed some elements of the Red
Gear, but no entry was required in the aircraft technical log upon fitment or
removal. A local accounting procedure was in place, but this was not used for
the mass fitting and removal of Red Gear during the Suez transit. No muster was
conducted prior to flying to ensure all the Red Gear had been removed.
Prior to sinking,
the left-hand intake blank was observed to float clear of ZM152’s wreckage and
was subsequently impounded. A salvage operation was mounted and the aircraft
was located and successfully recovered to the UK.
Cause
Following analysis
of the Flight Data Recorder by the manufacturer and having completed an
independent Airworthiness Review, the Panel has identified no technical issue
with the aircraft. It is the Panel’s opinion that it is almost certain that a
single engine intake blank remained inside the engine intake at the time of
launch, causing a restriction in airflow to the engine such that it was unable
to generate enough power for take-off.
Conclusion
Based on the
evidence obtained, the Panel is confident that the primary causal factor of the
event was the left-hand intake blank remaining in the aircraft prior to launch,
reducing the engine power. This was most likely due to a combination of human,
organisational and procedural factors. Nevertheless, the inquiry continues to
pursue a standard of evidence that will allow other lines of inquiry to be
addressed across a range of possible causes. The Panel is focussing on
potential mechanisms of movement of the intake blank and comparisons of UK
servicing procedures with other F-35 operating nations.
In accordance with
its terms of reference, the Service Inquiry continues to examine other factors,
including equipment design, workforce resource, fatigue management, quality
assurance and post-occurrence management of the event, to identify any relevant
lessons that may prevent reoccurrence and enhance Air Safety.
Source key.aero
