Military Human Factors Issue 00

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Flight Safety Is Everyone Action Military Human Factors

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Contents UH-1N Impact Terrain New Mexico.................................................................................................................. 3 Introduction ................................................................................................................................................... 3 Source ........................................................................................................................................................ 3 General data .............................................................................................................................................. 3 Accident brief description ......................................................................................................................... 4 Cause and contributing factors ................................................................................................................. 4 Accident detailed description ........................................................................................................................ 5 MF2’s troubleshooting sequence .............................................................................................................. 8 Impact ........................................................................................................................................................ 9 Human factors analysis................................................................................................................................ 10 1

Authorized Unnecessary Hazard ..................................................................................................... 10

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Channelized Attention ..................................................................................................................... 10

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Cross-Monitoring Performance ....................................................................................................... 10

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Miscommunication .......................................................................................................................... 11

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Inadvertent Operation..................................................................................................................... 11

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Mission Briefing ............................................................................................................................... 11

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Inadequate Rest............................................................................................................................... 11

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Training Aid ...................................................................................................................................... 12

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UH-1N Impact Terrain New Mexico

Source: U.S. AIB Report.

Introduction Source United States Air Force Aircraft Accident Investigation Board (USAF AIB).

Final report 042711_UH-1N_Kirtland.

General data Date: 27th April 2011.

Aircraft: UH-1N, T/N 69-6603.

Location: Near Kirtland Air Force Base (AFB), New Mexico (NM).

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Accident brief description

capsule’s window. The MA banked right and MP2 instinctively applied maximum power in an attempt to recover the MA. The MA entered a sharp descending right turn while tethered to the F-111 capsule. When the forest penetrator ripped free, the MPs leveled out the MA before impacting terrain. The MA’s main rotor struck the ground twice and the MA came to rest on its left side.

The United States Air Force Aircraft Accident Investigation Board (AIB) describe in their final report that: On 27 April 2011, at approximately 1115 local time, a UH-1N, T/N 69-6603, crashed at a remote landing zone near Kirtland Air Force Base (AFB), New Mexico (NM).

The MC egressed with no major injuries. A fire ignited shortly after impact completely destroying the MA.

The mishap crew (MC) was performing hoist operations when the rescue device, in this case a forest penetrator, snagged on a stationary F-111 capsule. The mishap aircraft (MA) entered a descending right turn and impacted terrain. After the MA came to a rest, the MC egressed the MA unharmed. The MA is assigned to the 512th Rescue Squadron, 58th Special Operations Wing, Kirtland AFB, NM. The MC was conducting an initial instructor flight engineer checkride involving hoist operations. The MC consisted of two pilots (MP1 and MP2) and two flight engineers (MF1 and MF2).

Cause and contributing factors The Accident Investigation Board (AIB) President found by clear and convincing evidence that the cause of the mishap was a combination of four actions by the mishap crew (MC), including three by the mishap flight engineers (MF1 and MF2) and one by the mishap pilot (MP2). These actions included: (1) MF2’s troubleshooting sequence,

During one of the hoist operations, the hoist cable was lowered to the ground with the forest penetrator attached. MF1 initiated a hoist malfunction to test MF2’s ability to troubleshoot. During the operation, the MA’s hover drifted forward and left. When MF2 cleared the malfunction the hoist cable retracted unexpectedly. When the cable retracted, the forest penetrator raised off the ground and swung forward, snagging a stationary F-111

(2) MF1’s checkride supervision, (3) MF2’s channelized attention, and (4) MP2’s control inputs.

In addition, the AIB President found by a preponderance of the evidence that the use of an old F-111 capsule as a training target during hoist operations and miscommunication between the crew substantially contributed to the incident.

Source: U.S. AIB Report.

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Accident detailed description The AAIB then explain in the report that the MC and FC started the mission as a formation.

Startup, taxi, and takeoff occurred without incident. The formation took off 12 minutes early at 0948L. The formation departed via the South Departure and proceeded to Site 37. While enroute to Site 37, the formation descended below 300 feet above ground level (AGL) to conduct tactical low-level operations, including two practice evasive maneuvers. The formation did three approaches at Site 37 with one goaround called by MF2. Upon completion of training objectives for the formation portion of the sortie, MC and FC disbanded the formation per the mission plan.

After, the MC flew to Site 15 to conduct remote operations. Site 15 is located in a bowlshaped depression along a series of ridgelines at an elevation of 5382 feet mean sea level (MSL).

The surveyed landing area is surrounded by rising terrain on the northeast and southwest sides.

Due to terrain, the best approach and escape headings are 110 or 290 degrees. The landing area is 263 feet long and 160 feet wide. An F-111 capsule was located on a downward slope approximately 145 feet northwest of and 12 feet lower in elevation than the landing area. The F111 capsule is an entire cockpit pod from an F111 usually resulting from an ejection. The capsule on Site 15 weighed 2,060 pounds and was missing multiple window coverings.

Source: U.S. AIB Report. Forest Penetrator with Retracted Seat Paddles.

The report said: the MC arrived at Site 15 at approximately 1055L. MP2 accomplished a site evaluation and landed in the surveyed landing area. While on the ground, the MC took a five minute restroom break.

After that, the MP1 took off, orbited, and came back around for a 50 foot Alternate Insertion/Extraction (AIE) near the F-111 capsule.

For the first AIE, MF1 assumed the role of the student and took control of hoist operations in order for MF2 to act as an instructor. The approach was performed into the wind with a northwest heading. MF1 directed the aircraft to hover 10 to 20 feet south of the F-111 capsule.

During the hover, MF1 purposefully made minor mistakes to simulate being a student, and MF2 corrected those mistakes as the instructor candidate. The MC concluded the first AIE without incident.

Source: U.S. AIB Report. F-111 Capsule with Snag Point and Forest Penetrator.

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Next, MF1 expressed that he wanted to see MF2 operate the hoist, so the MFs switched positions. MP2 assumed control of the MA and performed the next approach. MP2 performed an approach to the same spot as the first AIE and settled into a stable hover. MP2 held the hover between 44 and 48 feet, utilizing approximately 80 percent power. MF2 demonstrated operating the hoist, providing instruction to MF1 as he would to a student. MF2 lowered the cable and set the forest penetrator on the ground at the intended target, approximately 10 to 15 feet south of the F-111 capsule. Until this moment everything had gone as planned, it is then when the problems begin.

attempted to retract the hoist cable by using his pendant. MF2 noticed that the hoist was not retracting. MF2 began trouble-shooting the hoist malfunction in accordance with the 512th Standard Operating Procedures.

As part of the instruction the MF1 induced a failure with the object that the student in this case the MF2 performed the troubleshooting following the appropriate procedures.

MF2 announced to the MC that the cable was not coming up and asked the MPs if the hoist power was on. The MPs confirmed that it was on.

MF2 then asked the MPs if they could double check their circuit breakers, and it was confirmed that the circuit breakers were in. MF2 again checked his pendant. MF2 then misdiagnosed the simulated malfunction as a pendant failure. He then asked MP2 to raise the hoist cable by using the pilot hoist control switch on the pilot’s cyclic.

MP2 responded in the affirmative that he was using the pilot’s hoist control switch to attempt to retract the cable. MF2 announced that “nothing was happening.”

As MF2 was lowering the cable, MF1 leaned over MF2 and induced a simulated hoist malfunction by holding the up limit switch to the full up position. The up limit switch is designed to stop cable retraction once the cable fully retracts.

Holding the up limit switch up prevented the hoist from retracting the cable but allowed it to extend. In accordance with procedure, MF2

Upon seeing that MF2 had not yet correctly identified the simulated malfunction, MF1 interjected and queried MF2 on the cause. MF2 then looked at the hoist, noticed that MF1 was holding the up limit switch, and promptly identified and corrected the simulated malfunction by swiping MF1’s hand from the switch.

Source: U.S. AIB Report. Hoist Up Limit Switch and Hook.

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This is the key moment of the accident, the MP2 was still activating the pilot hoist control switch because the MF2 did not tell him that he should stop activating it. The MF2 should have instructed the MP2 to release the switch according to the approved procedure. MF2 did not confirm that MP2 had released the pilot’s hoist control switch before clearing the simulated

malfunction. This sequence resulted in an unanticipated full rate cable retraction.

Since the up limit switch was no longer activated, the cable immediately began retracting at full rate in the low speed setting (125 feet per minute). MF2 did not immediately notice the retraction. MF1 sat down in the transmission seat in the middle of the cabin to observe MF2.

Source: U.S. AIB Report. Pilot Controls.

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MF2’s troubleshooting sequence

penetrator snag in the front left F-111 capsule window and the cable became taut.

MF2’s Troubleshooting Sequence is as follow:

While MF2 was focused on the malfunction inside the cabin, the MA had an undetected drift forward and left, positioning the MA 5 to 10 feet west of the capsule. Upon clearing the simulated malfunction, MF2 looked back outside and noticed that the forest penetrator was already off the ground and swinging. Within approximately 2 seconds, MF2 saw the penetrator snag in the front left F-111 capsule window. He noticed the cable becoming taut and immediately called “stop up, stop up.” Neither MP1 nor MP2 heard this call.

The error in the execution of the procedure was as follows. The MF2 initially thought that the failure was due to the non-functioning of the pendant and therefore performed the first two steps of the corresponding procedure, see table below. When the pilot was pressing the hoist control switch he discovered that the problem was due to the Up-limit switch and instead of finishing the “Pendant Failure” procedure he had initiated and indicate to MP2 to stop acting on the hoist control switch, he changed directly to the procedure “Up limit switch failure” in his first step of "Ensure that the Up limit switch actuator is not stuck in the up position" without having previously made sure that the pilot stopped acting his hoist control switch.

MF2 channelized his attention on the simulated hoist malfunction, which drew his attention away from the MA’s hover position.

Ordinarily, MF2 would correct the hover before cable retraction. When the cable unexpectedly retracted, the MA was not over the forest penetrator.

The normal trouble shooting sequence for uplimit switch failure has the pilot try his hoist control switch two steps after the FE has already ensured the up limit switch actuator is not in the up position. MF2 executed the first steps of the pendant failure troubleshooting sequence followed by the first step for up limit switch failure. MF2 did not confirm that MP2 had released the pilot’s hoist control switch before clearing the simulated malfunction. This sequence resulted in an unanticipated full rate cable retraction.

The forest penetrator subsequently swung like a pendulum and lodged into the F-111 capsule.

MF2 made a "stop up, stop up" can after the forest penetrator hit and lodged into the F-111 capsule. This call was not successfully communicated to the MPs. Successful communication of this critical information might have reversed the pilot's actions on the collective and mitigated the ensuing rapid descent.

Due to the snag, the MA experienced a violent jerk, creating a right roll and right yaw. Based on the unexpected aircraft movement and abnormal control feel, MP2 instinctively pulled up on the collective, which would normally move the MA away from the ground. MP2 glanced inside and noticed the torque showing 100 percent or maximum power available. Simultaneously, MP1 placed his hand to the right of the cyclic to ensure that control inputs were not causing the right bank. MP1 noticed that the right bank was not being caused by the cyclic and decided to mirror the controls because of the MA’s erratic behavior.

Source: U.S. AIB Report. Hoist Troubleshooting Steps.

According to the AIB report, next came the second event of authentic bad luck, the

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The AIB report says the MA started a descending right turn which prompted MF1 to call for cable cut. MF2 reached for the cable cut switch on the back side of the hoist. With the hoist swung out for operations, the cable cut switch faced the inside of the cabin. MF1 initially saw both MPs on the flight controls, and attempted to reach the cable cut switch on the center console, but was unable to due to his restraining device. MP1 also reached for the center console to activate the cable cut switch.

MP2 remained on the controls attempting to recover the MA.

level the skids with the rising terrain.

Approximately 3 to 5 seconds passed between the cable snagging and the MA impacting the terrain. The cable was sheared by the hoist cable cut mechanism close to impact.

Impact The AIB report explains the Impact: The MA impacted rising terrain with an approximate 15 degree nose up attitude and a forward left drift. Effort was made to impact with the skids as level as possible in order to increase the chance of occupant survivability. Upon initial impact, the main rotor blades came in contact with the higher terrain to the northeast. This caused the nose of the aircraft to spin right and the fuselage to roll left. The MA came to rest on its left side. Even though MF1 and MF2 were wearing restraining devices, the impact and left roll tossed both of them onto the left side of the cabin MP1 and MP2 remained restrained in their seats throughout the impact.

The MA turned to a northeastern heading, positioning itself into a direct crosswind from the northwest. At that point, the forest penetrator ripped free from the F-111 capsule. The MA departed from its radial path and slid left and forward towards the rising terrain. Just prior to impact, MP1 returned to mirroring the flight controls. Both MP1 and MP2 realized that they could not recover the MA and applied aft cyclic to

Source: U.S. AIB Report. Approximate Mishap Terrain Vertical Reference

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Human factors analysis The report continued with HUMAN FACTORS ANALYSIS: The Department of Defense Human Factors Analysis and Classification System (DoD-HFACS) is a systematic and comprehensive tool that is comprised of a list of potential human factors that can be contributory or causal to a mishap.

A total of seven human factors were identified and described below for this mishap.

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Authorized Unnecessary Hazard

Authorized Unnecessary Hazard is a factor when supervision authorizes a mission or mission element that is unnecessarily hazardous without sufficient cause or need. This includes intentionally scheduling personnel for missions or operations that they are not qualified to perform.

coverings were missing at the time of the mishap.

Without these panels, the capsule was an entanglement hazard. Previous site surveys noted the F-111 capsule’s presence. Multiple members in the 512 RQS verified that the capsule was a frequently-used reference point for AIE operations. MF1 selected an aim point for the hoist approximately 10 to 15 feet from the capsule.

The F-111 capsule had been on Site 15 for over a decade. At one point aluminum sheeting covered all the openings, but several panel

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Channelized Attention

Channelized Attention is a factor when the individual is focusing all conscious attention on a limited number of environmental cues to the exclusion of others of a subjectively equal or higher or more immediate priority, leading to an unsafe situation. This may be described as a tight focus of attention that leads to the exclusion of comprehensive situational information.

pilots’ inputs for aircraft position and altitude, and monitoring the hoist during its operation.

MF2 channelized his attention on troubleshooting the hoist malfunction. MF1 was focused on his student’s actions. Due to MF1 and MF2’s channelized attentions, neither initially noticed the aircraft drifting or the hoist cable retracting and lifting the penetrator.

The FE is responsible for clearing the aircraft of obstacles on the side and rear, directing the

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Cross-Monitoring Performance

Cross-Monitoring Performance is a factor when crew or team members failed to monitor, assist or back-up each other's actions and decisions.

language, head movements, and verbalizations.

After MF2 cleared the hoist malfunction, MF1 sat and observed MF2 raise the hoist cable. Since MF1 was sitting and no longer standing over MF2, he was unable to visually monitor the forest penetrator. This placed him in a position where he could not quickly recognize and correct the impending unsafe situation.

All instructors and evaluators are tasked to immediately correct breaches of flight safety.

MF1 stated he was able to monitor students’ abilities and the situation by observing their body

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Miscommunication

Miscommunication is a factor when correctly communicated information is misunderstood, misinterpreted or disregarded.

hear a stop up call. This discrepancy displays a communication issue. MF2 may have made the statement and it may have been unintentionally disregarded by the pilots.

Both FEs state a “stop up” call was clearly communicated by MF2. MP1 and MP2 did not

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Inadvertent Operation

Inadvertent Operation is a factor when individual’s movements inadvertently activate or deactivate equipment, controls or switches when there is no intent to operate the control or device. This action may be noticed or unnoticed by the individual.

and MF2 failed to ensure that MP2 was not activating the pilot’s hoist control switch when the up limit switch was released. As a result, the hoist cable retracted inadvertently.

MF2 made a "stop up, stop up" can after the forest penetrator hit and lodged into the F-111 capsule. This call was not successfully communicated to the MPs. Successful communication of this critical information might have reversed the pilot's actions on the collective and mitigated the ensuing rapid descent.

MF1 controlled the up-limit switch on the hoist and simulated a malfunction. MF2 eventually identified the simulated malfunction and swiped MF1’s hand away from the switch, releasing the hold on the cable retraction. MF1

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Mission Briefing

Mission Briefing is a factor when information and instructions provided to individuals, crews, or teams were insufficient, or participants failed to discuss contingencies and strategies to cope with contingencies.

briefed. This part of the brief covered AIE contingencies, including transfer of cable cut authority. MF1 had attended multiple AIE briefs in the past and even though he was fully aware of how to cope with those contingencies, his attendance at that brief was expected and required.

The AIE portion of the brief was conducted without MF1 present, and he was not back-

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Inadequate Rest

Inadequate Rest is a factor when the opportunity for rest was provided but the individual failed to take the opportunity to rest.

two days prior to the MS. Per squadron policy, he was given one day prior to the day MS to shift his sleep cycle. MF2 did not change his sleep schedule on his day off and only slept for 5 hours the night prior to the MS.

All crewmembers were afforded sufficient time for crew rest. MF2 was on a night schedule

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Training Aid

The F-111 capsule was utilized routinely as an aide for both search training and alternate insertion and extraction (AIE) events. The capsule's deterioration increased the likelihood that a rescue device could entangle with the

capsule. Though increasing the realism of the training, the routine use of the capsule as an AIE reference and training target unnecessarily increased risk.

LucĂ­a Ferraz, Juan Urrutia, Product and Flight Safety.

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