455th vAccident Investigation Board (AIB) Report - F16CM 96-087

[Posohm]

455 vAIR EXPEDITIONARY WING​

vAccident Investigation Board (AIB) Report​

Mishap Aircraft (MA): F-16CM, S/N 96-087
Unit: 8th vFS, 455th vAEW
Flight Callsign: WOOL1
Mishap Date: 20 Sep 2025
Airspace: NTTR Caliente A
Mission: TR-1
Crew: Upgrading Pilot (UP) - ejected, uninjured
Other Aircraft: Safety-chase IP (non-mishap)
Damage: Aircraft destroyed (post-ejection impact)

1. Authority and Purpose​

This vAIB short form is organized consistent with USAF practice under AFI 51-307 and the format exemplified in public F-16 AIBs (Authority/Purpose; Sequence of Events; Maintenance; Systems; Weather; Crew Qualifications; Medical; Operations & Supervision; Human Factors; Governing Directives; Statement of Opinion). The purpose of the report is for entertainment and learning only in DCS.

2. Accident Summary​

During HARTS training in NTTR Caliente A, the MA departed controlled flight from a very nose-high, low-energy condition and entered an erect deep stall. Yaw developed during the stall. In this condition the yaw-rate limiter uses the horizontal tails for roll, reducing pitch authority; with a 300-gal centerline tank and wing stores this often requires multiple well-timed MPO (Manual Pitch Override) pitch-rock cycles to produce sufficient nose-down pitch rate for recovery. The UP attempted recovery but did not execute a correctly phased MPO sequence. As the aircraft approached 10,000 ft AGL, the IP directed ejection. The UP ejected at 19:16:17.356Z; the MA impacted terrain about 62 seconds later. The deep stall was determined to be recoverable based on simulation replications with correct technique and prior training exposure.

3. Background​

Unit/Aircraft: F-16CM assigned to 8 vFS, 455 vAEW.
Sortie type: B-course TR-1 (first flown ride in Transition Phase), with safety-chase IP. The B-course WST-5 simulator event (emergency procedures incl. out-of-control recoveries) was omitted from the syllabus in this cohort’s flow.

4. Sequence of Events (telemetry unless noted; Zulu times)​

a. Mission. Training sortie emphasizing high pitch attitudes, AOA management, and recoveries (HARTS). Stores/fuel below.
b. Planning. Routine local training authorization under the B-course program; see §10 for syllabus omission.
c. Preflight. No discrepancies presented to AIB; Code-1 release.
d. Summary of Accident.
• Pre-departure setup (mission/telemetry): ~31,500 ft MSL, ~60° nose-high, ~127 KCAS. A brief oscillation carried the nose to ~70° at ~25° AOA, followed by departure and stabilization into an erect deep stall.
• Deep-stall window: Attitude remained nose-high with oscillatory motion and yaw development; telemetry shows max recorded pitch +52.4° (nose-high) and peak yaw-rate ~21 °/s.
• Ejection: 19:16:17.356Z, ~15,218 ft MSL (~10,011 ft AGL) - IP-directed as UP approached 10,000 ft AGL following unsuccessful recovery attempts.
• Impact: 19:17:19.246Z (≈ 62 s post-ejection).
e. Impact. Post-ejection, unmanned MA descended to ground impact (uninhabited terrain).
f. Egress and AFE. UP initiated ejection upon IP direction; ACES II performance was nominal; no injury reported.
g. SAR. v66 RQS scrambled from Nellis to pickup.

The stall behavior (oscillatory, yaw present, need for multiple MPO cycles when properly phased) matches F-16 test report deep-stall descriptions, particularly with centerline and wing-loaded configurations.

5. Maintenance​

Forms/Inspections/Procedures/Supervision/Fluids/Unscheduled: Reviewed; Code-1, no open discrepancies; no evidence of maintenance causal factors (structure, engine, hydraulics, electrical) per short-form review, consistent with vAIB maintenance checklisting.

6. Airframe/Systems (salient to event)​

(1) CSFDR/Telemetry. Telemetry establishes 19:16:17.356Z ejection; ~15,218 ft MSL/~10,011 ft AGL; max pitch +52.4°; peak yaw-rate ~21 °/s. (AoA and airspeed traces around ejection not available to AIB.)
(2) FLCS/DFLCC (Flight Controls). Behavior consistent with deep-stall neutral band (~50–60° AoA) where full nose-down stabilator produces negligible nose-down moment; MPO pitch-rock is required to create nose-down pitch rate through the neutral band. Proper cadence ≈ 3 seconds per half-cycle; do not confuse yaw/roll oscillations with pitch.

7. Weather​

a. Forecast/Observed: Day VMC, Temp 21 °C, QNH 29.65 inHg, Clear, Vis ≥ 6 SM.
b. Winds: SFC 000/0 kt; 6,600 ft 182/16 kt; 26,000 ft 214/23 kt.
c. Space Environment: N/A.
d. Operations: Weather not a factor.

8. Crew Qualifications​

UP: IFF Track E graduate; 23.0 hrs F-16 (455th); 11 flights/30 days; last sortie 14 Sep 2025 (Basic Intercept). Emergency Procedural Training checkout not completed prior to HARTS.
IP (Safety Chase): 8 vFS IP, current/qualified; 15/30, 28/90, 86/365, 146.1 hrs with the 455th. The IP directed ejection as UP approached 10,000 ft AGL following unsuccessful recovery attempts.

9. Medical​

UP: qualified; no reported health, toxicology, crew rest, or lifestyle issues relevant to the mishap.

10. Operations and Supervision​

Operations. Sortie was a B-course TR-1 event in local training airspace (Caliente A).
Supervision/Authorization. Authorization for this sortie profile was implicit via the B-course design then in effect; WST-5 (Simulator: Emergency Procedures and Instrument Practice) was omitted from the syllabus prior to Transition Phase. WST-5 covers critical action procedures, emergency procedures, and out-of-control recoveries (upright and inverted), among other tasks. The omission is assessed as a programmatic deficiency creating inadequate training exposure for emergency out-of-control recoveries before HARTS execution.

11. Human Factors (HFACS )​

AE103 - Training Deficiency (Individual): UP lacked hands-on high-AOA/MPO exposure; recovery requires muscle-memory timing and phasing under stress.
OP003 - Inadequate Training Program (Organizational): WST-5 omission removed simulator exposure to out-of-control recoveries prior to TR-1/HARTS.
PP102 - Inadequate Procedural Guidance/Publication (Program/Syllabus): Syllabus flow allowed HARTS execution without prior MPO deep-stall practice, contrary to long-standing high-AOA training best practices.

12. Governing Directives and Publications (selected)​

AFI 51-307 (Aerospace and Ground Accident Investigations); DAFI 91-204; applicable F-16 Dash-1/-34 extracts.

Statement of Opinion​

1. Opinion Summary​

By a preponderance of the evidence, the MA departed controlled flight into an erect deep stall during HARTS maneuvering. The UP’s ineffective MPO recovery (timing/phasing) in a low-energy state and oscillation-prone configuration (CATM-120C on 1/9; AIM-9X on 2/8; 300-gal centerline) with yaw development prevented recovery. The IP appropriately directed ejection as the MA approached 10,000 ft AGL; ejection occurred at 19:16:17.356Z.

​

2. Cause​

Loss of aircraft following departure from controlled flight into an erect deep stall with ineffective MPO recovery execution (timing/phasing) in a low-energy condition and yaw-excited, centerline-loaded configuration. The observed stall/yaw behavior and required MPO technique match the F16 test flight descriptions (MPO cadence ≈ 3 s per half-cycle; beware yaw-rate-limiter use of tails for roll, which reduces pitch authority and may require multiple cycles).

3. Substantially Contributing Factors​

• OP003 - Inadequate Training Program / Authorization via syllabus design. WST-5 simulator (EPs incl. out-of-control recoveries) was omitted prior to TR-1/HARTS, denying the UP required exposure.
• AE103 - Training Deficiency (individual exposure). UP had not completed a emergency out of control recovery checkout; improper cadence/phasing under stress is a known pitfall without hands-on practice.

4. Conclusion​

The deep stall was deemed to be recoverable with correct MPO technique and prior training exposure. The IP-directed ejection was timely and appropriate.

Safety Recommendations​

1. Re-introduce WST-5 to the Ground School syllabus (mandatory, pre-TR-1).
   • Placement: Ground School Phase, completed before Transition Phase / TR-1.
   • Scope (no waivers): Emergency Procedures + Out-of-Control Recoveries (upright & inverted), instrument unusual attitude recoveries, and at least one EP flown to a logical conclusion; at least one approach HUD-out.
   • Exit criteria: Demonstrated MPO pitch-rock proficiency (timing/phasing) on at least two consecutive correct cycles in the sim, including a yaw-excited deep-stall case (centerline tank modeled).
2. Issue a Wing Safety Bulletin (WSB) to restore and protect currency.
   • Immediate action: Publish a WSB directing all B-course and TX students to complete WST-5 prior to high-alpha/HARTS sorties; suspend HARTS until WST-5 sign-off is logged.
3. Configuration-specific brief (standing item).
   For 300-gal centerline + 1/9 & 2/8: brief yaw-rate limiter using tails for roll (reduced pitch authority), likely need for 2–4 cycles, and the requirement to come off MPO once the nose truly falls.