1、Lessons Learned Entry: 1597Lesson Info:a71 Lesson Number: 1597a71 Lesson Date: 2005-04-20a71 Submitting Organization: DFRCa71 Authored by: Mark NunneleeSubject: E-2C Wing Scrape Close Call Abstract: A Navy E-2C Hawkeye aircraft was in the NASA Dryden Flight Loads Laboratory (FLL) for a series of win
2、g and tail loads calibration tests. A Close Call incident occurred in the FLL on December 13, 2004, when an “H”-Beam structure unexpectedly leaned outward and made contact with the top of the wing when structure was being removed from the right wing of the Navy E-2C Hawkeye aircraft. The “H”-Beam st
3、ructure had been used to keep the wing from deflecting upward and the aircraft from “rolling” while the under-wing load pads were being bonded to the aircraft. The contact occurred four feet inboard of the wingtip directly above the wings main spar. Damage consisted of scraped paint over an area app
4、roximately 1.5” by 2” and two small scratches. The damage was deemed “negligible” by the on-site Navy Representative. It was determined that the primary factor for this incident was the overhead crane operators misjudgment on the amount of tension that was applied to the two nylon safety straps that
5、 were utilized to support the “H”-Beam structure when restraining cables were disconnected. The slack in the “choker” loops was enough to allow the structure to lean outboard approximately 15. Other identified contributing factors were poor crew coordination, performing steps out of sequence, and fa
6、ilure to use written procedures. Description of Driving Event: On December 13, 2004, the load pad bonding structures, placed below and above the right wing of the E-2C, were being moved to the left wing. The Overhead Crane Operator, who was also acting as the Operation Leader, conducted a quick Safe
7、ty Briefing with the crew members to explain the activities planned for the operation. The first task was to remove the under-wing structure and move it to the left side of the aircraft. To achieve this task, nylon straps were utilized to support the “H”-Beam structure upright while the forward cabl
8、e guides were removed from the “H”-Beam structure. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-The straps were used in a “choker” fashion around the upper corners of the “H”-Beam structure and the Overhead Crane Operator took up the slack with th
9、e Overhead Crane and reported that the straps looked to be tight. The two forward cable guides were then removed. The “H”-Beam structure at this point was supported by the two aft guide cables, the floor bolts and the nylon straps attached to the overhead crane. The under-wing structure was then mov
10、ed safely to the left wing of the aircraft. The next task was to remove the over-wing structure from the right wing and move it to the left side of the aircraft. The Overhead Crane Operator instructed the Lab Mechanic to remove the bolts that secure the “H”-Beam structure to the floor. After the flo
11、or bolts were removed, two electronics technicians (technicians were utilized due to a shortage of mechanics) proceeded to loosen and remove the aft cable guides without the knowledge of the Overhead Crane Operator who was distracted at the time. The outboard-aft cable guide was removed first, and t
12、hen the inboard-aft cable guide was removed. As soon as the inboard-aft cable guide was removed, the structure started leaning outboard due to the cable guides being removed and the slack in the “choker” loops of the nylon straps. The outriggers that were above the wing and attached to the “H”-Beam
13、structure came in contact with the top of the wing before the slack in the nylon straps was taken up. The impact with the wing was low due to the “H”-Beam structure being supported by the overhead crane and nylon straps. The result of the wing contact was scraped paint and two minor scratches in the
14、 aluminum skin of the wing right above the main wing spar. There were no injuries as a result of this incident. Lesson(s) Learned: 1. Nylon straps have a significantly higher amount of “stretch” than most other lifting hardware. Alternative methods should be used when supporting structure in close p
15、roximity to an aircraft or other equipment.2. During a lifting or supporting process, “choker” loops will continue to tighten and release more of the strap length until the load takes all the slack out. Alternative methods should be used when supporting structure in close proximity to an aircraft or
16、 other equipment.3. In most instances, removing hardware from an existing upright structure should be accomplished in reverse order from the installation procedure.4. A written procedure and a detailed crew brief would have specified the step-by-step process to the crew members and could have preven
17、ted this incident.5. An Operations Manager or Lift Manager who was removed from the process would have directed the steps in an orderly fashion and could have prevented this incident.Recommendation(s): 1. When supporting upright structure in close proximity to an aircraft or other equipment, use cle
18、vises or hoist rings where applicable in combination with wire-rope cables. This will minimize the stretch, as in nylon straps, and eliminate the need for “choker” loops.2. When applicable, remove supporting hardware in reverse order of the installation process. Loosening and removing the floor bolt
19、s last could have prevented this incident.3. When working in close proximity to aircraft or other critical equipment, use written Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-procedures to detail each step of the process. Hold a crew brief to expl
20、ain the steps in the written procedure to all of the crew members.4. Included in written procedures should be a list of the minimum personnel required and their required disciplines to accomplish the task. Additionally, include a step to rope off the hazardous area to keep people not included in the
21、 activities at a safe distance. The roped off area should also be large enough to eliminate distractions from people not included in the hazardous activity.5. An Operations Manager or Lift Manager, who is removed from the process with no other distractions, should be utilized to oversee the process
22、of all hazardous operations. An Operations Manager or Lift Manager could have identified one or more of the issues and could have prevented the incident.6. The authority of the Operations/Lift Manager should be equivalent to a test director having ultimate authority of the roped off area and the haz
23、ardous activities. This authority should be communicated in writing to all FLL members that may participate in or witness hazardous activities.Evidence of Recurrence Control Effectiveness: 1. A written procedure was utilized and a crew brief was given prior to removing the “H”-Beam structure from th
24、e left wing.2. “H”-Beam structure support hardware was removed in reverse order during removal process form the left wing.3. An Operations/Lift Manager, who was removed from the process with no other distractions, was utilized to oversee the process of the removal of the “H”-Beam structure from the
25、left wing.4. There were no incidents during the removal of the “H”-Beam structure from the left wing.Documents Related to Lesson: Dryden Center Policy, DCP-S-009Mission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Aeronautics Researcha71 Space OperationsAdditional Key Phrase(s): a71 Aircraf
26、ta71 Ground OperationsProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Human Factorsa71 Lifting Devicesa71 Mishap Reportinga71 Safety & Mission Assurancea71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 2006-04-17a71 Approval Name: dkruhma71 Approval Organization: HQProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
