NTSB Factual Report

HISTORY OF FLIGHT

On June 6, 1999, about 2316 Pacific daylight time, a Boeing 747-4F6B, N751PR, collided on the ground with a Boeing 747 SP-44, F-GTOM, at the Los Angeles International Airport (LAX), Los Angeles, California. When the collision occurred N751PR, operated by Philippine Airlines as flight 103, was taxiing for takeoff with an intended destination of Manila, Philippines. F-GTOM, operated by Corsair as flight 942, was parking following its arrival from Paris, France. Onboard the Philippine airplane were 4 flight deck crewmembers, 16 cabin attendants, and 405 passengers. None of the 425 occupants were injured. Onboard the Corsair airplane were 4 flight deck crewmembers, 9 cabin attendants, and 261 passengers. None of the 274 occupants were injured. In close proximity to the Corsair airplane were two United Airlines mechanics and four Hudson General LLC ground support personnel. None was injured. Both airplanes were operated as scheduled, international, passenger flights under 14 CFR Part 129. Visual meteorological conditions prevailed during the nighttime collision that occurred as the Philippine airplane taxied for takeoff in a westerly direction on taxilane "C," and collided with the Corsair airplane, which had stopped in a northwesterly direction short of its assigned gate 101, at the Tom Bradley International Terminal (TBIT). The Philippine airplane received minor damage. Its right winglet was severed. The Corsair airplane's left wing was substantially damaged. (All time references in this report are converted to Pacific daylight time, and are based upon the 24-hour clock.)

F-GTOM (Corsair) Arrival and Delayed Parking.

About 1110, F-GTOM departed from Paris, and about 2236, it landed at LAX's runway 25L. The crew advised Federal Aviation Administration (FAA) air traffic control tower personnel (ATC) that its assigned arrival gate was 101. (See the Jeppesen airport diagram and the airport layout charts for a view of the taxiways, taxilanes, and gate locations.) At 2236:41, ATC advised the crew that gate 101 was occupied (by N751PR), and to hold short of the gate. The crew acknowledged the clearance and held its position.

N751PR (Philippine) Delayed Pushback.

N751PR's scheduled 2230 pushback from TBIT gate 101 was delayed because of an onboard passenger medical emergency. About 2301, N751PR's crew advised ATC that their airplane was ready to be pushed back from the gate. ATC issued N751PR instructions to pushback in a tail west direction (onto taxi lane "C") for a runway 25R departure. The crew repeated the pushback instructions to ATC, to which ATC stated, "that's correct."

The captain reported to the National Transportation Safety Board investigator that he repeated the ATC pushback instructions to the tug driver responsible for the pushback. The captain stated that the driver confirmed receipt of the instructions. Thereafter, the tug driver initiated the pushback in a direction opposite that of the captain's instructions.

ATC observed that N751PR's ground service crew was pushing the airplane in a tail east direction. At 2305:19, ATC amended its clearance and instructed the crew to continue the easterly pushback until the airplane was positioned south of the American satellite, east of "C-10." The pushback process continued, and the ground crew disconnected its tow tractor from N751PR when it was located south of the American satellite.

F-GTOM (Corsair) Taxi to Parking, Procedure, and Captain's Statement.

At 2311, ATC instructed F-GTOM to taxi to gate 101 via a left turn on taxiway "B" and a right turn at "taxiway Charlie ten." The crew repeated the instruction and proceeded toward the gate. En route, F-GTOM taxied in a northerly direction and crossed in front of the west facing N751PR, which was holding on taxi lane "C" to the east of "C-10."

During the subsequent accident investigation, on June 9, 1999, the Corsair captain reported that he followed the lead-in line toward the terminal building as he approached TBIT gate 101. The airplane's taxiing was stopped upon observing a stop signal from his ground marshaller.

Within about 45 minutes after the accident, the captain provided a statement to a Los Angeles City Airport Police Bureau uniformed officer. In pertinent part, the captain reported that a ramp agent (marshaller) had ordered him to stop taxiing the airplane in order to connect the tow bar.

In another statement, the captain wrote, "so we stopped the plane, set the parking brake, shut down all the engines. The ramp agent connected [a communication line] to the aircraft. At this time we felt a shock...." The captain also reported that during this sequence of events the airplane's navigation lights and the beacons remained "on."

The captain also reported that he had observed (on the side of the building at TBIT gate 101) that the guidance system light box (aka the docking light station) was "completely dark" and "no lights were on." (The docking station is designed to provide lateral guidance and closure information to the flight crew when power-in procedures are used to taxi the airplane to the gate.)

The captain indicated to the Safety Board investigator during the interview that contrary to the printed statement on the Jeppesen airport diagram chart, he did not advise ground control that his airplane was not completely blocked at the terminal gate or that his airplane was partially obstructing taxi lane "C." The captain asserted that, until the collision occurred, he was not aware his airplane needed to be towed to the gate.

United Airlines Mechanics' Statements.

Two United Airlines mechanics, which were under contract with Corsair to provide a walk around inspection of the airplane and related duties upon its arrival, reported that they observed the Corsair airplane approach TBIT gate 101 directly on the lead-in line.

As the Corsair airplane approached the gate, a Hudson ground service employee directed the flight crew to stop taxiing. The airplane came to a stop and all engines were shutdown. A tow tractor was already positioned in front of the gate in anticipation of the Corsair airplane's arrival. One of the mechanics plugged in his headset and began communicating with the Corsair crew.

The mechanic reported that the first communication he made with a flight crewmember was "ground to cockpit." A crewmember replied, "this is cockpit." Then the mechanic reported that he said "set brakes," because he planned to insert the bypass pin into the nose gear to lock out the nose steering.

The collision occurred less than 1 minute after the Corsair airplane had come to a stop. (The FAA participant reported that the mechanic's (head set operator's) "set brakes" instruction should have alerted the captain that the airplane was to be towed. The instruction typically given to a captain when the airplane has reached the gate is "chocks in" to signal to the captain that it is safe to release the brakes.)

N751PR (Philippine) Taxis toward the Departure Runway.

At 2313:17, ATC issued the following clearance to the crew of N751PR, which was holding its position on taxilane "C" at "C-10:" "...when able taxi ahead on charlie to papa turn left at papa onto bravo eastbound taxi to runway two five right." A N751PR crewmember read back the clearance. According to the captain, the airplane then taxied at a slow rate of speed via taxi lane "C's" centerline in a westerly direction toward taxiway "P."

N751PR (Philippine) Taxi procedure and Captain's Statement.

The captain and his crewmembers indicated that they observed the Corsair airplane, and they were aware that a few minutes earlier it had taxied to TBIT gate 101. The captain stated to the Safety Board investigator that he was handling the airplane's controls. He indicated that he and his crew observed a ground service employee (wing walker) with a lighted night wand standing near the Corsair airplane's tail. The wing walker was observed making a signal that the Philippine crew reported interpreting as an "all clear to taxi" sign for their airplane. Accordingly, the Philippine captain continued taxiing past the Corsair airplane. The captain stated that he was certain he was taxiing on the centerline, and then he commenced a left (southbound) turn toward taxiway "P," pursuant to his clearance. The first officer was monitoring the right wing tip's clearance. The collision occurred upon turning about 30 degrees of arc. The estimated speed of the airplane during the turn was between 6 and 8 knots. About 2316, the crew advised ATC that "...we have hit something I mean our right wing tip."

Philippine First Officer's Statement.

The first officer reported that he observed a marshaller behind the Corsair airplane. The marshaller signaled to go ahead. The first officer stated, "I cleared our right wing as we passed behind the parked Corsair 747. Then we started our turn to the left towards taxiway 'P.' I looked towards the direction of our turn. Then we felt a shudder during the turn."

Philippine Captain's Explanation.

The captain indicated that the Corsair's navigation lights were illuminating. However, neither its upper nor lower beacon lights were visible.

According to the captain, he realized that he was close to the Corsair airplane, so he further reduced his taxi speed to give his crew more time to observe the situation. He was aware that he had not received any cautionary statement from ATC regarding the Corsair's position as possibly blocking the taxiway, so he had no doubt that he was in the clear. Additionally, his crew observed a marshaller (also known as a wing walker) positioned near the right-hand tail side of the Corsair airplane. The marshaller was holding a lit wand and was signaling by waving the wand in a manner to indicate that the airplane should continue taxiing forward; it was a motion to alert the crew that it was "clear" to proceed.

The captain reiterated his belief that his path was clear upon stating, "four pairs of trained eyes in the cockpit could not have possibly mistaken a stop from a go signal." The captain stated that the marshaller never issued the "stop" taxi signal. However in retrospect, he wondered whether the marshaller had given him "a wrong signal."

The captain additionally reported that the marshaller was observed with one lit wand. The wand was in the marshaller's left hand, and it was being waved in a counter-clockwise direction.

As an afterthought, the captain reported that it was possible the marshaller, whom he and his crew observed located in proximity to the Corsair airplane's right horizontal stabilizer, may have initially been gauging only the decreasing distance between the approaching Philippine airplane's right wing tip and the Corsair's tail. The marshaller's signal may have only indicated the fact that there was adequate room for the Philippine airliner to pass the Corsair's tail.

None of the Philippine crew indicated that they ever observed a second marshaller positioned near the Corsair airplane's left wing. Also, none stated that they had observed anyone at any location near the Corsair airplane attempt to stop their taxiing by motioning using the customary signalman's stop signal.

INJURIES TO PERSONS

None of the 699 occupants onboard the airplanes were injured during the collision. None of the 6 ground service personnel were injured when airplane wreckage was blown across the tarmac by jet blast from the turning Boeing 747-4F6B.

PERSONNEL INFORMATION

Flight Crew.

The captains from both airplanes reported having previous experience parking at LAX. The Corsair captain stated that he was not familiar with the parking procedure at the TBIT gate 101.

The Corsair captain also reported that his total flying experience was 12,046 hours. His experience flying the Boeing 747-SP was not indicated. During the preceding 90-day period, he had flown the airplane for 182 hours.

The Philippine captain's total flying experience was 19,700 hours. His experience flying the Boeing 747-400 was 650 hours. During the preceding 90-day period, he had flown the airplane for 180 hours.

The Philippine first officer reported that his total flying experience was 6,000 hours. His experience flying the Boeing 747-400 was 885 hours. During the preceding 90-day period, he had flown the airplane for 290 hours.

Ground Support Personnel, and Training.

The two United Airlines mechanics had no marshalling responsibility. The Corsair airplane was marshaled in by employees of Hudson General LLC, the ground service company with whom Corsair management had contracted to render parking and related services.

Hudson's on-scene ground support operation for the Corsair airplane consisted of the following persons being present: one supervisor, one lead marshaller, and two wing walkers. Pertinent background, employment, and training information were reviewed for these persons. No discrepancies were noted.

AIRPLANE INFORMATION

Visual Angles.

Boeing Company data indicates that from the captain's left seat position in a Boeing 747-400, the right winglet is not visible. It is visible from the first officer's right seat position.

Regarding the visual angle from the cockpit of a Boeing 747 SP, the Boeing Company indicates that in order for the flight crew to observe an object on the ground directly ahead of the airplane, it must be located about 84 feet 8 inches in front of the pilot's eye position. Or, when measured from the airplane's nose gear location, the object must be 92 feet 4 inches in front of the gear.

Ground Distance, Boeing 747 SP to Gate.

LAX airport management provided measurements of the available distance between the Boeing 747 SP's nose gear stop line that was observed painted on the ground in front of TBIT gate 101, and the location where a signalman could physically stand at a marshalling location in front of the terminal building. The management indicated that the distance was approximately 60 feet.

Wingspan.

According to the Boeing Company, the wingspan of a Boeing 747-400 airplane (with winglets) is 211 feet 5 inches, when empty. When operating at its maximum gross weight and fully loaded with fuel, its wingspan (the maximum distance from wingtip to wingtip) becomes 213 feet 0 inches, as the fueled wings bend downward. The distance between the airplane's longitudinal axis (centerline) and each wingtip is, therefore, 106.5 feet.

Wing Growth.

Due to the Boeing 747-400's swept wing design and its landing gear geometry, when the airplane turns sharply, obstacles (such as a building or another same elevation wingtip) located within 12 feet of the airplane's wingtip can be impacted. Effectively, during a sharp turn a wing "grows" 12 feet because it swings outward, relative to the airplane's point of rotation.

The Boeing Company indicates that when turning, a pilot must therefore assure himself that this "extra" clearance exists. The minimum wing tip clearance required to avoid obstacle contact during a sharp turn is 106.5 feet plus 12 feet, or a total of 118.5 feet.

METEOROLOGICAL INFORMATION

In pertinent part, about the time of the accident LAX reported its weather as follows: Wind from 220 degrees at 4 knots; visibility 7 miles; scattered clouds at 1,000 feet; and temperature/dew point of 61/55 degrees Fahrenheit. No precipitation was reported.

COMMUNICATION

Neither pilot reported experiencing any malfunction of communications capability. No ATC communication impediments were reported.

AIRPORT AND GROUND FACILITIES

Docking Lights.

LAX airport management reported that several years prior to the accident, the airport installed an airplane docking light system on the side of the terminal building for TBIT gate 101. Following its installation, it was calibrated and functionally tested. The docking light system was designed to provide a means for pilots to taxi all the way up to the terminal gate thereby eliminating the previous practice of stopping short of the gate, waiting to be connected to a tow tractor, and then minutes later being towed in. When airplanes stopped short of the gate, at times they par

NTSB Probable Cause

Airport management's failure to ensure that its current operating procedure, which required the arriving airplane to power into the terminal gate, was being used. Also causal was (1) the ground service company's utilization of an outdated arrival procedure that directed the arriving airplane to stop short of the gate, thereby obstructing the taxilane; and (2) the ground service company's utilization of a nonstandard marshalling hand signal which was, accordingly, misinterpreted by the departing airplane's crew. A contributing factor was the departing airplane's first officer's misjudged evaluation of wing tip clearance.