Newark, NJ, USA
N78008
Boeing 777-200
During a near maximum gross weight takeoff from runway 4L, in gusty winds, the captain recalled that the airplane's rotation was normal, but it did not "fly away" as he expected. As the captain continued to rotate the airplane, the tail section struck the ground, and the "tail strike" EICAS (Engine Indication and Crew Alerting System) message illuminated. The flight crew then completed the takeoff sequence, completed all checklists, jettisoned fuel, and returned to the airport where an uneventful landing was made. The winds recorded at the airport, about 1 minute after the accident, were from 280 degrees, at 21 knots, gusting to 28 knots. Review of the DFDR data revealed that at the time the takeoff roll began, the captain's control wheel was turned 25.5 degrees to the left, resulting in the upward deflection of the left wing outboard aileron, flaperon, and 6 of 7 spoilers, which was consistent with a correction for crosswind conditions. As the takeoff roll continued, the control wheel input varied between 19.6 degrees and 37.5 degrees to the left, and at the approximate point of rotation, the control wheel was turned to the left 38.4 degrees. The control column position also began to move aft at the point of rotation, with a force of 22.7 pounds, and the pitch of the airplane rose to 3 degrees nose up. As the pilot continued the rotation, he held the pitch control at a value consistent with previous recorded flights, before pulling the control column further aft, increasing the pitch angle to the tail strike attitude of approximately 13 degrees nose up. One second later, as both left and right main gear indicated no weight on wheels, the control column position reached its maximum value during the event, 9.2 degrees aft, and the pitch reached 17.8 degrees nose up. A Safety Board vehicle performance study compared the airspeed and groundspeed recorded during the accident, and determined that a wind gust caused an approximate 7 knot loss in airspeed, the lateral control wheel input during the rotation ranged from 24 to 37 degrees, and the maximum pitch rate during the rotation was approximately 6.0 degrees/second. Using these data in a Boeing estimation method, it was determined that three factors contributed to the reduced tail clearance during the takeoff. These factors were the loss of airspeed that resulted from a tailwind gust during the rotation, the loss of lift that resulted from the deflection of the lateral control surfaces, and a pitch rate in excess of that recommended. These factors combined for a total reduction in tail clearance of approximately 150-170 percent. It was concluded in the performance study that reducing the pitch rate to the Boeing recommended 2.5 degrees/second would have brought the tail clearance reduction to the 80 percent to 100 percent of nominal level, and from that point, a 1-knot increase in rotation speed would have provided about a 7 percent increase to the tail clearance margin. According to Boeing, the typical liftoff attitude was 8.5 degrees, the minimum tail clearance was 37 inches, and the tail strike pitch attitude was 12.1 degrees up. The operator's flight manual warned pilots to "Avoid any tendency to rapidly rotate to a 10 degree pitch attitude and hold it until lift-off. This technique invites a tail strike." In addition, neither Boeing, nor the operator, had procedures or policies for adding an increase in rotation speed to compensate for crosswind or tailwind conditions.
HISTORY OF FLIGHT On March 2, 2005, at 1550 eastern standard time, a Boeing 777-200, N78008, operated by Continental Airlines as flight 99, experienced a tail strike departing from the Newark Liberty International Airport (EWR), Newark, New Jersey. There were no injuries to the 2 certificated airline transport flight crewmembers, 2 relief flight crewmembers, 12 flight attendants, or 198 passengers. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan had been filed for the flight destined for Hong Kong, China. The flight was a scheduled international passenger flight, conducted under 14 CFR Part 121. According to a representative of the operator, the airplane was departing from runway 4L, an 11,000 foot-long by 150 foot-wide, asphalt runway. As the airplane rotated, during the takeoff, it lifted off the runway, momentarily settled back to the ground, and lifted off a second time. Suspecting that the tail of the airplane struck the ground, the pilot elected to return to the airport, where it landed uneventfully approximately 1-hour later. According to the captain, who was flying at the time of the accident, the fuel load was approximately 251,000 pounds, which resulted in a gross weight takeoff of approximately 623,500 pounds. The takeoff was planned and briefed with the air conditioning packs "OFF" and with a "full power" thrust setting. The reported winds for takeoff were "very gusty" and variable. The ACCULOAD data for takeoff was planned with a 7-knot tailwind and a "low altimeter setting penalty" (ACCULOAD was a computer based weight and balance system, which was an integral part of the flight operations management system, and was used to generate the pilot weight manifest. Takeoff data was based on the most recent observed metrological and runway conditions). During the takeoff roll, the indicated airspeed "lagged" slightly before V1 and Vr, but stabilized and accelerated normally after rotation. The rotation was normal at, or after Vr, but the airplane did not "fly away" as he expected. The airplane cleared the ground, but a wind gust forced it back down, and the tail of the airplane struck the ground with a "substantial impact." The "tail strike" EICAS (Engine Indication and Crew Alerting System) message then illuminated. The flight crew completed the takeoff sequence, completed all applicable checklists, jettisoned fuel, and returned to Newark for landing. In a subsequent statement, the captain recalled that the flight received takeoff clearance from the tower, with the winds reported as 280 degrees at 17 knots. According to the first officer, he was the "pilot monitoring" for the accident flight. Before takeoff, all normal checklists and briefings were completed in accordance with company flight operations procedures. Before taxiing onto the runway, he noted that the tower controller stated that wind gusts of plus or minus 10 knots were reported by another airplane. The takeoff was briefed with air conditioning packs "OFF," as planned per the ACCULOAD. Engine spool up was normal and stabilized about 99 percent rpm. As expected, the indicated airspeed was erratic during acceleration due to the gusty wind conditions. Prior to the V1 speed callout, the indicated airspeed stagnated momentarily, and then "jumped" quickly up to the V1 speed. The jump in indicated airspeed was so quick, that the "automated voice" called V1 before the first officer did (synthetic voices annunciate certain normal but time critical operational information, such as the V1 callout). The first officer then announced, "V1, rotate," and recalled that the speed difference between V1 and Vr was one knot. The captain initiated the rotation, while the first officer turned his attention to the airspeed indicator to advise of any further airspeed anomalies. He then observed that the airspeed stopped increasing for a few seconds. As the airplane "seemed" to pitch up normally, the first officer noticed that the airspeed stagnated, again, just above "V1/Vr." Therefore, his attention was fixated on the airspeed indicators. After several seconds, the airspeed began its normal acceleration toward V2. Once the first officer observed this acceleration, he looked up and noticed a high pitch angle. He then rationalized that with this high pitch angle, the airplane must be airborne. He looked back inside the cockpit to confirm a positive rate of climb and then felt a firm ground impact. The airplane seemed to fly up and away from the ground as expected; however, shortly thereafter, the "tail strike" EICAS indication illuminated. The flight crew continued the climb out and subsequently returned to Newark, where the airplane landed uneventfully. In a subsequent statement, the first officer recalled that the flight received takeoff clearance from the tower, which included winds from 280 degrees at 17 knots. The tower provided no further information, and the flightcrew elected to not add a gust factor to the takeoff data. PERSONNEL INFORMATION The captain held an airline transport pilot certificate with a rating for airplane multiengine land, and held a flight engineer certificate. The captain held type ratings in Boeing 727, 737, 747, 757, 767, 777, Airbus A-300, and McDonnell Douglas DC-9 and DC-10 airplanes. The operator reported that the captain had accumulated about 17,000 hours of total flight experience, which included 4,100 hours in the Boeing 777. The captain's most recent Federal Aviation Administration (FAA) first class medical certificate was issued on October 16, 2004. The first officer held an airline transport pilot certificate with a rating for airplane multiengine land. The first officer was also type rated in the Boeing 777. The operator reported that the first officer had accumulated about 15,000 hours of total flight experience, which included 3,438 hours in the Boeing 777. The first officer's most recent FAA first class medical certificate was issued on March 15, 2004. AIRCRAFT INFORMATION The airplane was maintained under a continuous airworthiness inspection program, and had accumulated about 27,782 total hours of operation, at the time of the accident. METEOROLOGICAL INFORMATION The 1451 EWR METAR reported winds from 280 degrees, at 17 knots, gusting to 23 knots. Peak winds from 280 degrees at 26 knots were recorded at 1430. The 1551 EWR METAR reported winds from 280 degrees, at 21 knots, gusting to 28 knots. Peak winds from 280 degrees at 30 knots were recorded at 1528. AIR TRAFFIC CONTROL According to the FAA Air Traffic Control Handbook, 7110.65L, Section 5. Runway Selection, "3-5-1 Selection a. Except where a 'runway use' program is in effect, use the runway most nearly aligned with the wind when the wind is 5 Knots or more or the "calm wind" runway when the wind is less than 5 Knots (set tetrahedrons accordingly), unless use of another runway: 1. Will be operationally advantageous, or, 2. Is requested by the pilot. b. When conducting aircraft operations on other than the advertised active runway, state the runway in use. NOTE - 1 - If a pilot prefers to use a runway different from that specified, he/she is expected to advise ATC. 2 - At airports where a 'runway use' program is established, ATC will assign runways deemed to have the least noise impact. If in the interest of safety a runway different from that specified is preferred, the pilot is expected to advise ATC accordingly. ATC will honor such requests and advise pilots when the requested runway is noise sensitive." At the time of the accident, Newark Airport was utilizing an "Informal Runway Use Program." According to the Newark Airport Informal Runway Use Program: A. The procedures described in Attachments 1 and 2 shall be used for runway selection except when one or more of the conditions listed below exist. At those times, the runway(s) most nearly aligned with the wind will be assigned, unless use of another runway will be more operationally advantageous. 1. Wind shear reported by either pilot or the "TDWR" or "ITWS." 2. A thunderstorm in the initial takeoff departure path. 3. Snow, slush, ice, or standing water on the runway to be used. 4. Braking actions less than GOOD or reports of hydroplaning or unusually slippery surfaces. 5. If runways are dry, the crosswind component must not exceed 20 knots, and the tailwind component must not be greater than 5 knots. 6. If runways are wet, the crosswind component must not exceed 15 knots, and the tailwind component must not be greater than 3 knots. B. Participation in the program is voluntary for aircraft operators/pilots. Whenever a request is made for other than the assigned runway, the pilot will be advised that the requested runway is not the noise abatement runway. If the assigned runway is still unacceptable, the pilot will be assigned the runway requested. Note- Due to the interaction between surrounding air traffic facilities in the metropolitan area, the final authority for runway selection has been delegated to the Operations Manager on duty at the New York TRACON. Review of Attachment 2 of the Newark Airport Informal Runway Use Program, revealed that the maximum allowable wind velocity, including gusts, for runway 4L, with winds from 280 degrees, was 14 knots. FLIGHT RECORDERS The digital flight data recorder (DFDR) was removed from the airplane and sent to the Safety Board's Vehicle Recorder Division in Washington, D.C. The recorder was subsequently downloaded, and contained approximately 61 hours of data. The accident flight was the last recorded event, and its duration was approximately 1 hour and 2 minutes. Review of the DFDR data regarding flight control wheel position (CWP) revealed that at 15:49:55, as groundspeed increased through 8 knots, the CWP was 25.5 degrees counter clockwise (CCW). The captain's CWP decreased to 19.6 degrees CCW at 15:50:04 with a groundspeed of 43 knots. As groundspeed increased over the next 24 seconds, values for the captain's CWP were recorded between 20.2 degrees CCW and 37.5 degrees CCW. The highest captain's CWP recorded prior to pitch increasing was 38.4 degrees CCW at 15:50:28. At this time, the groundspeed was 150 knots and the left inboard and outboard ailerons were approximately 12 degrees trailing edge up. Review of the DFDR data regarding flight control column position revealed that at the time the takeoff roll began, the force on the captain's control column was approximately -10 pounds (forward pressure on the column). At 15:50:30, at an airspeed of 156 knots, the control column position began to move aft, and the captain's force on the control column was 17.2 pounds (aft pressure on the column). Two seconds later, at an airspeed of 162.5 knots, the control column position reached 5.4 degrees aft, and the captain's force on the control column was 22.7 pounds (aft pressure on the column). Pitch increased to 3.0 degrees airplane nose up (ANU) and the nose wheel indicated no weight on wheels. At 15:50:34, vertical acceleration reached 1.699 g's, which was the maximum value during the event. Pitch increased to 12.5 degrees ANU, and airspeed was 161.5 knots. The control column position was 6.5 degrees aft, and the captain's control column force was 25.7 lbs. One second later, the control column position reached its maximum value during the event, 9.2 degrees aft. The highest elevator value during the event was also recorded at this time, with the left inboard elevator at 22.3 degrees, trailing edge up (TEU). At 15:50:36, both left and right main gear indicated no weight on wheels, and pitch reached 17.8 degrees ANU. Data was also extracted from the recorder for the airplane's previous takeoff for comparison reasons. During the previous takeoff, with an airspeed of 145.0 knots, pitch began to increase to 0.9 degrees ANU and the nose wheel indicated no weight on wheels. Control column position was 5 degrees aft, the captain's control column force was 19.1 lbs, and the highest elevator value during the takeoff was recorded, with the left outboard elevator at 8.2 degrees TEU. At an airspeed of 166.5 knots and a pitch of 6.0 degrees ANU, the left main gear indicated no weight on wheels. The following second the right main gear indicated no weight on wheels. WRECKAGE AND IMPACT INFORMATION A Federal Aviation Administration (FAA) inspector and representatives of Boeing and the operator examined the airplane after the accident. Scrape marks were observed on the underside of the airplane's tail section. Further examination revealed substantial damage to the aft pressure bulkhead. TEST AND RESEARCH A Performance Study was conducted by the Safety Board's Research and Engineering Division. The Performance Study utilized the data provided to the flight crew for the accident flight in determining calculations. According to the Performance Study, the airplane's takeoff roll took place in a quartering tail wind, which was recorded by the DFDR, from 280 degrees at 21 knots, with gust to 28 knots. This required the input of 24 to 37 degrees of control wheel input into the crosswind during the rotation. The airplane's rotation began approximately at the planned 158 knot rotation speed, but a gust that produced an approximate 10 knot tailwind component occurred during the rotation. The change in tailwind component represented approximately an 11 percent loss in lift and a reduction in tail clearance. The Performance Study also stated that, Boeing had developed a method, largely based on flight test, to estimate the effects of airspeed, pitch rate, and lift coefficient (through control wheel input) on aft body clearances during takeoff. The estimation method was based on flight test data, basic aerodynamics, and analytical methods. The recommended takeoff rotation speeds and pitch rate were set to provide safety margin for stall and/or aft body clearance, which ever was more critical. Anytime a takeoff rotation deviated from the nominal liftoff airspeed, pitch rate, or lift coefficient (by crosswind lateral control input raising the flight spoilers) the aft body clearance would be impacted. Comparing the airspeed and groundspeed recorded for the accident, it was revealed that a wind gust caused an approximate 7 knot loss in airspeed, the control wheel input during the rotation ranged from 24 to 37 degrees, and the maximum pitch rate was approximately 6.0 degrees/second. Using these numbers in the Boeing estimation method, it was determined that the total tail clearance reduction was approximately 150-170 percent. It was concluded in the performance study that reducing the pitch rate to the Boeing recommended 2.5 degrees/second would have brought the tail clearance reduction to the 80 percent to 100 percent of nominal level, and from that point, a 1-knot increase in rotation speed would have provided about a 7 percent increase to the tail clearance. According to Boeing, the typical liftoff attitude of the 777-200 was 8.5 degrees, the minimum tail clearance was 37 inches, and the tail strike pitch attitude was 12.1 degrees. Boeing also reported that turning the control wheel resulted in the upward deflection of the respective wings outboard aileron, flaperon, and 6 of 7 spoilers. ADDITIONAL INFORMATION According to the ACCULOAD manifest used for the takeoff, the V1, VR, and V2 speed were calculated as, 157, 158, and 164 knots respectfully. After the airplane landed, all of the baggage on board the airplane was counted and weighed. It was discovered that an additional 2,992 pounds of baggage was loaded on board the airplane than what was originally calculated for use by the flight crew. This resulted in a gross takeoff weight of approximately 626,523 pounds for takeoff. The maximum gross weight for takeoff was 629,200 pounds. Takeoff Training and Procedures The operator provided pilots with company Boeing 777 flight manuals for training and operational use. The information provided in the flight manuals was derived from numerous sources, to include the Boeing 777 Flight Crew Training Manual (FCTM). The Boeing 777 FCTM was an advisory manual, which provided
The captain's failure to follow company procedures, which resulted in a tail strike. Contributing were the gusty crosswind and tailwind conditions, and the manufacturer's failure to provide adequate performance planning data to account for gusty crosswinds during takeoff.
Source: NTSB Aviation Accident Database
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