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Lessons Learned from the Inadvertent in-flight Termination of a Tomahawk Cruise Missile CDR Eric “Homey” Holmberg Chief Test Pilot, VX-31 - 8 May 2008. NAVAIR Public release YY 08-229 Distribution: Statement A – “Approved for Public Release”; Distribution is unlimited.
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Lessons Learned from the Inadvertent in-flight Termination of a Tomahawk Cruise Missile CDR Eric “Homey” Holmberg Chief Test Pilot, VX-31 - 8 May 2008 NAVAIR Public release YY 08-229 Distribution: Statement A – “Approved for Public Release”; Distribution is unlimited.
Lessons Re-Learned (or Not Learned) from the Inadvertent in-flight Termination of a Tomahawk Cruise Missile CDR Eric “Homey” Holmberg Chief Test Pilot, VX-31 - 8 May 2008 NAVAIR Public release YY 08-229 Distribution: Statement A – “Approved for Public Release”; Distribution is unlimited.
Test Background Facts • Tomahawk Facts: • Contractor: Raytheon Company (Tucson, AZ) • Unit Cost: $729,000 (FY 04-08 Multi-year) • Propulsion: Solid-fuel thrust-vectoring booster – Ship or Submarine Launched Turbofan cruise engine (550 lbs thrust) • Weight: 2,900 pounds (3,500 pounds with booster) • Range: 700 - 1350 nautical miles • Speed: High-Subsonic • Payloads: 1000 lb class, Conventional Unitary, Conventional Sub munitions, Nuclear • Dates Deployed: IOC - 1986; Block III - 1994; Block IV – 2004 • Reasons for Test: • Development and Operational Test of New Variants and enhanced capabilities • Verification of Fleet Inventories • Fleet training
Tanker 52 53 51 Many test assets – Lots of Test Money. • Scheduling: • -Ships Schedule • -Training • -BriefsX2 • -Three Range Periods • -Four Aircraft blocked off for one week • Test Package: • -Two Ranges • -FAA/LA Center/Low Level • -Two weapopns • Sea Range Clearance Aircraft and Boats • Launch Submarine • 3 FA-18s for Chase • KC-135 Tanker • P-3 for telemetry relay • Two Recovery Helicopters (capable of lift) • Range Control Groups both at Pt. Mugu and China Lake • Flow Overview • 2 FA-18s on missile • Tanker shadows package high, at ~15K MSL • 1 FA-18 hangs on tanker, works FAA comms & traffic calls P-3
Remote Command and Control (RCC) System • The RCC is operated by an Airborne Missile Flight Safety Officer (AMFSO) in the aft seat of each F/A-18. • Take Navigational Control of the Tomahawk • Air Traffic and Weather Avoidance • Correct Navigational Errors • Terminate the Tomahawk in the event of an emergency • Each F-18 carries two Tomahawk Control Pods. • Pod controller mounted on either left or right aft side console.
The Pressure is on. • First Launch attempt: Day 1 (23 JUL) • TFR Delayed shot • NOTAM cancelled by FAA over weekend – was a mistake. • Unable to Open IR-200 - MISSION CANCELLED • DAY 2 (24 JUL, 319Q) • Failed Launch Attempts • DAY 3 (25 JUL, 319QR) • Day of the Inadvertent Termination
Chase Aircraft Launch Timing 1+30 1+00 MISSILE BOOST HDG 350-400 KIAS COSO-52 500 FT COSO-51 500 FT 45 DEG 3/4 TO 1 NM SEP AT LAUNCH 0+00 3-5 SEC IN TRAIL INBOUND @ BOOST HDG +45 DEG 0+30
52 Tanker 53 51 P-3 N Transition to China Lake Land Ranges
Tanker 52 51 Brief Lost Sight P-3 N
Tanker 52 51 Coso 51 passes control to Coso 52 and proceeds to tanker P-3 N
Tanker 52 51 Coso 51 Rejoins and asks for control back P-3 N
RCC Control Transfer • Control Transfer accomplished by on-coming AMSFO turning his power on, while off-going AMFSO turns his power off. • Off Going AMFSO • Confirmed Control Room ready and On-coming AMFSO was ready • “RCC swap in 3,2,1 … Off”
Weapon is Terminated • Program Office Reaction?
So what went wrong? • Off-going AMFSO inadvertently actuated Terminate switch instead of Power switch. • Simple – he moved the wrong switch ! But how? Why? • Failure investigation board established. • Many Lessons that apply not just to cruise missile test but to testing of any system with flight termination or crew vehicle interfaces where critical functions are a single switch throw away.
Main Causal Factor • Human Factor: AMFSO mis-prioritized procedural responsibilities by not visually verifying proper switch activation and substituted terminate switch for the planned power switch. • “No fast hands in the cockpit !” • AMFSO looked at switch, placed hand on it, removed hand, then started count down. • Other lesser tasks were distracters: • Maintaining sight of weapon following lost-sight. • Simultaneously keying mic, counting down “control transfer in 3,2,1….off”.
Other Causal Factors • Supervisory factor: Inadequate function and design of the control panel elevated the risk for inadvertent termination switch activation. • Power and Terminate Switches identical • Limited Real Estate = very close switches • Panel location in aircraft not ideal • Terminate switch lacked two-step“are you sure?” functionality.
Other Causal Factors • Supervisory factor: Test Team, Chief Test Pilot and Chief Test Engineer failed to accurately assess the hazard of inadvertent termination activation and ensure mitigating steps were developed. • Hazard and risk analysis didn’t think of this one and therefore did not develop a THA to mitigate it. • Human factors analysis of control box had been previously completed with no issues • Of course THAs now exist. • Supervisory factor: Incomplete training was provided on the function and design of the control panel.
Other causal factors • Supervisory Factor: The Test Wing “Firebreaks” Instruction was not broad enough to apply a two-step switchology to flight termination systems (FTS). • Firebrakes are procedures/rules created to address accidental weapons firings/releases. • 1992: USS Saratoga Sea Sparrows versus Turkish destroyer. • Accomplished this by requiring two “firebreaks” or a two-step safety process when there is no intent for release. • Until very recently – did not apply to FTS systems which have similar risks to people and property.
Lessons Learned • No fast hands in the cockpit. • Task Prioritization is critical • Look, think, act slowly before you throw the big switch • Deficiencies in Crew-Vehicle Interface, even for flight test systems, can and will bite you eventually. • Take the time to human-engineer controls • There’s almost always a hazard out there that you probably didn’t think about – or mitigate. • Installation of an FTS system carries numerous new hazards. You need to ensure those hazards outweigh the benefits. • Aircrew “get-it-done attitude”. Cultivating test aircrew to question 'why' things are designed this way and 'what if-ing' the consequences of those designs can raise awareness to potential risks. • Sufficient training is critical in reducing flight-test risk. • Critical functions with potentially catastrophic results must have an “are you sure” step – or a two step process.