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Attrition

Repor t

US Air Force Aircraft
Accident Investigation
Board report into the
loss of a USAF Air Demonstration
Squadron (USAFADS – The
Thunderbirds) F-16D at Dayton,
Ohio, last June (see Attrition,
August 2017, p90), was released
on November 3. The report
identifies the aircraft involved
as 91-0466 – Thunderbird ‘8’.
The Accident Board President,
Col Jason W Evenson, found by
a preponderance of the evidence
that the cause of the mishap was
landing with excess airspeed
and insufficient distance to
stop the jet on the wet runway.
Substantially contributing factors
were environmental conditions
affecting vision, misperception
of changing environment, and
procedures followed incorrectly.
On June 23, 2017, at 1231hrs
local time, the Block 52 F-16D,
assigned to the Thunderbirds as
part of the 57th Wing at Nellis Air
Force Base, Nevada, departed
the prepared runway surface at
James M Cox Dayton International
Airport (KDAY) and overturned,
injuring the mishap pilot (MP),
although the mishap crewmember
(MC) was uninjured. Neither
personnel, who are assigned
to the USAFADS, attempted
to eject. The mishap aircraft
(MA), valued at $29,268,599,
was destroyed. The crash also

damaged one runway light, one

runway approach light and the

grass off the end of the runway.

The incident occurred during a

familiarisation sortie for the MC,

with the MP demonstrating the

capabilities of the F-16 and the

manoeuvres performed by the

USAFADS. It was scheduled

to have been the first of three

such flights that day. The MA

had departed from KDAY at

approximately 1115hrs local time

on an instrument flight rules (IFR)

clearance to start the flight. The

weather at KDAY was reported as

broken at 900ft (274m), broken

at 1,500ft (457m) and overcast

at 2,500ft (762m); winds 340° at

17kts, gusting to 20kts; 1½ miles

(2.4km) visibility with heavy rain

and mist. Prior to landing, Dayton

Tower advised the MP there was

previously reported wind shear

and extreme precipitation over the

field at KDAY. The MP executed

a missed approach on the first

approach to KDAY, unable to see

the runway environment because

of standing water on the canopy

that obscured his vision. During

the missed approach, the water on

the canopy dissipated, allowing the

MP to see the runway environment

and the pilot received holding

instructions from Columbus

Approach Control to wait for

the weather to clear at KDAY.

After holding for approximately

30 minutes, MP proceeded

on vectors to the instrument

landing system (ILS) approach

to KDAY Runway 6 Left (6L).

The MP had adequate fuel to

attempt one approach to KDAY

then divert to Wilmington Airport

if necessary. On final instrument

approach to Runway 6L, the MP

again experienced standing water

on the MA’s canopy, directly in

front of the head-up display (HUD),

obscuring his forward vision,

blurring the HUD and rendering it

unusable so the MP transitioned

his instrument cross-check to the

cockpit instruments. The MP flew

the MA into a right yaw so that the

turn enabled the MP to visually

acquire the runway environment

at the left 11 o’clock visual

position, to the left of the HUD.

The MP considered the

crosswinds and wind shear

and planned to fly a faster

approach of 160-165kts. The

Crash Survivable Flight Data

Recorder (CSFDR) shows the

MA maintained approximately

200 Knots Calibrated Airspeed

(KCAS) on final approach. The

MA crossed the runway approach

end threshold at approximately

193kts, which was 43kts faster

than the Technical Order calculated

approach airspeed. This excess

airspeed significantly increased

the distance required to land. The

CSFDR showed a fuel weight of

1,665lb (755kg) and a total MA

weight of 22,288lb (10,109kg) at

landing. Computed approach

and landing speeds for the

MA at this weight are 150kts

and 138kts, respectively.

The MA landed on Runway 6L,

approximately 4,764ft (1,452m)

down the wet runway, 25kts

above computed touchdown

speed, leaving 6,137ft (1,870m) of

prepared surface available to stop

the aircraft prior to the overrun.

The MP maintained more than

190kts for the first 2,000ft (609m)

of the runway then pulled back

the throttle, slowing to 178kts at

3,000ft (914m) down the runway.

Data shows the MP unintentionally

induced forward stick pressure

during the three-point landing roll,

which increases landing distance,

in addition to pulling the aircraft

to the right. The MP was unable

to stop the MA on the prepared

surface. It entered the overrun

at approximately 50kts in a skid

to the left; four seconds later the

MA departed the overrun, the

nose undercarriage collapsed,

and the starboard wingtip dug

into the ground, causing it to

overturn in the grass. The MP

was able to shut the engine

off with the assistance of the

MC. Dayton Tower immediately

cleared pre-positioned crash,

fire and rescue onto the runway

to begin rescue operations.

A

Thunderbirds F-16

crash report

Above: Thunderbirds F-16D 91-0466 lies inverted on the grass beyond the end of the runway at Dayton International Airport following its accident on June 23,

2017. USAF

http://www.airforcesmonthly.com #358 JANUARY 2018 // 89