A-10

Flying Safety, Jan, 2001 by Kurt Saladana

Once again, the A-10 community had an admirable mishap rate of 1.63 per 100,000 flying hours in FY00. Unfortunately, one of the two A-10 Class A mishaps cost the life of a pilot.

The first Class A of the year involved a relatively inexperienced pilot recovering from a routine training mission to a wet runway, which could have been icy. According to the Accident Investigation Board (AIB), the pilot landed softly rather than firmly, depleting little energy at touchdown. He deployed speed brakes and performed aerodynamic braking, but did not retard the throttles all of the way to idle. At no time did the pilot visually confirm that the throttles were at idle, nor did he check the engine instruments. Rather than testing braking action after the nose gear touched the runway, the pilot delayed braking until well down the runway. Unable to stop the aircraft, the pilot ejected after passing the departure end barrier. The aircraft continued off the end of the runway, the nose gear collapsed, and the nose section sustained severe structural damage forward of the cockpit seat rails.

While it is easy to read an account of this mishap and criticize the pilot, it is difficult to determine exactly what control measures would have prevented the accident from occurring. When you teach students or are conducting mission-ready training, do you discuss cold weather or icy runway conditions? It's doubtful that the schoolhouses, because of their locations, stress ice- or snow-covered runway techniques, which do differ from landing on a wet runway. A student could conceivably leave the schoolhouse in the spring and complete mission-ready training prior to ever seeing cold weather operations. Do units have the resources, hours and time to conduct thorough cold-weather work-ups? Lack of a trainer or a simulator makes it difficult to assess technique. HUD tapes could be used, but the tendency is to review tactical work rather than scrutinize how a line pilot lands his or her aircraft. Does anyone ever pull Turbine Engine Monitoring System (TEMS) data to see how a pilot set the throttle on landing? Bef ore this mishap, it's doubtful anyone would have thought of looking at this type of record, and even if they did, would they have the time and would they get the required support from maintenance? How do you assess a pilot's crosscheck? Flying on the wing permits instructors to assess a student's air work, but is there a way to really confirm that all of the necessary cockpit work is completed? People make mistakes-the best way to make sure they don't is to provide them with the best information available and to validate their understanding of this information. The mishap rate is low, but it is stagnating-the only way to further reduce it, yet keep flying tactically, will be to identify possible areas of increased risk and come up with innovative ways of reducing this risk. Maybe pulling TEMS data is worthwhile as a random sampling method of confirming student or upgrade pilot actions.

FY00's second Class A mishap cost the life of an experienced aviator. Recalled from a night training mission due to worsening weather, the mishap pilot flew an instrument approach through clouds based at 500 feet AGL and topped at 4500 feet MSL. He deviated below minimum altitudes and, while in a turn, impacted the ground and sustained fatal injuries.

This type of mishap is usually attributed to either pilot disorientation or instrument failure, which can lead to disorientation. Spatial disorientation is not unusual, but pilots are trained early in their careers to trust their instruments and work through the symptoms until it's possible to use external references. Mistrust in the instruments would make it very difficult to compensate for the effects of spatial disorientation. The A-10 fleet suffers from main ADI problems with reported failures including off flags, jittery behavior, and bank and pitch errors, all of which remain failed or return to normal operation. Maintainers replaced the main ADI six times in the year prior to the mishap. The mishap aircraft also experienced other malfunctions, including the heading and altitude reference system, directional gyro and the inertial navigation unit, all of which could affect the ADI presentation. No physical evidence indicated any instrument or aircraft failure prior to ground impact.

What could have been done to prevent this mishap? If the pilot did become disoriented because of an ADI anomaly, or could not work through the symptoms of spatial disorientation because of mistrust in the ADI, the answer lies in replacing the instrument or using other available trustworthy instruments. The ADI is being replaced. Unfortunately, the field was late identifying that the ADI needed replacement; when pilots started reporting the malfunctions in numbers great enough to flag a problem, the time delay to procure and install a suitable substitute took the USAF to a date well past that of this accident.

Relying on available trustworthy instruments means being proficient flying partial-panel. Pilots practice partial-panel regularly using the standby attitude indicator, but if it were off by 20 degrees in bank and five degrees in pitch, would it be good enough to help overcome disorientation? The standby attitude indicator can also precess rapidly. It used to be common to practice true partial-panel, i.e., using the altimeter and airspeed, vertical velocity, turn and slip and heading indicators. This type of flying is demanding and takes practice, but it pays dividends, particularly when a standby attitude indicator is added to the crosscheck--the pilot can quickly determine any errors and compensate for them.