OPS topics

Flying Safety, Sept, 2004

Editor's Note: The following accounts are from actual mishaps. They have been screened to prevent the release of privileged information.

Here are a few cases of bird strikes to our valuable aircraft that caused Class B damage. What are you doing to prevent a mid-air with wildlife?

KC-10 BBQs Poultry

This was a local pattern training sortie and while established on final approach and in landing configuration, the crew witnessed multiple white/brown flashes (birds) pass off the left side of the aircraft. The crew then reported a thump, a slight shudder, and a momentary No. 1 engine vibration. All engine indications remained normal. The crew then reported the smell of scorched poultry coming through the air conditioning. They immediately shut down the No. 1 air conditioning pack and the smell dissipated. The instructor pilot (IP) took control of the aircraft, disconnected auto-throttles, and left the No. 1 engine at the same throttle position as when the incident occurred until landing. The IP landed and the aircraft was shut down with no further incident. Postflight inspection revealed feathers and blood spatters on the spinner cone and acoustical panels inside the No. 1 engine. Also, the trailing edge of the left inboard flap had minor structural damage. Another blood streak was noted with no damage on the outboard flap.

The engine was removed and shipped to the manufacturer where it was broken down for damage assessment. Extensive bird debris and damage was found throughout the engine. So much bird debris was found in the fan section that a true damage assessment could not be determined until the fan section underwent a comprehensive cleaning. Over 292 blades were found damaged in the compressor stages. Both the fan and compressor sections had evidence of blade shingling. There was damage to the outlet and inlet guide vanes, high pressure compressor section (both casing and blades) and combustion can. All damage was consistent with bird ingestion.

F-15D Meets Black Vulture

The mishap flight was flown as a safety chase for an environmental evaluation test mission. Takeoff and departure were uneventful. During the course of the sortie, the test aircraft experienced a flight control anomaly and declared an emergency. The mishap aircraft (MA) chased the test aircraft to a full stop landing. After the low approach, the MA was directed to report a local pattern entry point. The mishap instructor pilot (MIP) in the rear cockpit took control of the aircraft to update backseat-landing currency. On one-mile initial at 1600 feet MSL and 300 KIAS, the mishap pilot (MP) in the front cockpit saw two large vultures co-altitude on the left side of the aircraft. The MP did not have time to take control of the aircraft and maneuver away from the vultures. A black vulture impacted the aircraft on the left No. 1 engine inlet ramp and was ingested by the No. 1 engine. Both pilots felt the impact and retarded the left throttle to idle, noting normal engine idle indications. The aircrew heard a "humming" sound from the left engine and smelled an acrid smell in the cockpit. They noted no fire indications or unusual engine readings and left the engine running in idle to maintain a backup source of hydraulic and electrical power. The MP took control of the aircraft declared an IFE and landed uneventfully. Maintenance investigation revealed sheet metal damage to the No. 2 and 3 inlet ramps. Inspection of the No. 1 engine revealed extensive damage to the fan and core module. The damage was the direct result of ingesting a black vulture into the No. 1 engine.

F-16C and Bird Fly Same Low-Level Route

The mission was the second sortie of a scheduled two-ship double turn day. The sortie was briefed as a low-level strategic attack mission with emphasis on lightning pod work in the training area. Bird condition for the route of flight on both sorties according to the bird avoidance model (BAM) and avian hazard advisory system (AHAS) was moderate 2. Brief, ground operations, takeoff, departure and entry into the low-level were uneventful. The mishap pilot (MP) flew the exact same route and low-level on the first sortie and saw no bird activity. Approaching a turn point on the low-level route, while executing low-altitude tactical navigation, the MP saw a large bird out the front of the aircraft and immediately pulled back on the stick to avoid impact. The MP felt a definite impact, heard a loud bang and smelled burning feathers. The pilot zoomed the aircraft and began a climbing turn toward base, declaring an IFE. Climbing through 21,400 MSL approximately a minute after impacting the bird, MP felt a loud bang and experienced a compressor stall. After alleviating the compressor stall, MP emergency jettisoned the external fuel tanks and climbed through 27,500 MSL with the engine operating normally. MP then elected to fly a straight-in SFO and landed uneventfully.

Postflight inspection found remains on the underside of the radome, in the ECS ducts, and all throughout the engine intake. The continuous wave / directional antennae on the front underside of the aircraft had been sheared off. Burnt bird remains were evident throughout the aft section of the engine.