|Title:||Tailstrike on landing, Airbus A300-600R, February 6, 1997|
|Micro summary:||This Airbus A300-600R encountered a tail strike during landing at St. Johns, Antigua.|
|Event Time:||1997-02-06 at 1440 AST|
|Publishing Agency:||National Transportation Safety Board (NTSB)|
|Site of event:||St John Antigua,|
|Departure:||Luis Muoz Marín International Airport, San Juan, Puerto Rico|
|Destination:||VC Bird International Airport, Saint John's, Antigua, Antigua|
|Airplane Type(s):||Airbus A300-600R|
|Type of flight:||Revenue|
NTSB short summary:
The captain failed to establish and maintain a stabilized approach (or perform a go-around), and applied excessive pitch rotation during the subsequent recovery from a bounced landing, resulting in a tail strike. A factor contributing to the accident was the operator's inadequate procedures to address corrective actions if an approach becomes unstabilized.
The scheduled flight from San Juan to the Antigua (ANU) area was uneventful. During the VOR 07 approach, at about 2,500 feet AGL, the flight maneuvered to avoid TCAS traffic. The runway was in sight. The captain was flying the transport category airplane on final approach with 40 degrees of flaps. At 1,000 feet, on the final approach to landing, the first officer made the company procedural 1,000 foot verbal callout and the captain brought the power above idle. The crew stated that the airplane was slightly high at 1,000 feet and by 500 feet they were 'in the slot' with airspeed about 20 knots above the reference speed of 128 knots and decreasing. Flight recorder data indicated that during the final approach segment from about an altitude of 500 feet to the ground, the airspeed decreased from 143 knots to 135, the pitch attitude increased from 1/2-degree nose up to 9 degrees nose up, the descent rate decreased from 1,700 feet per minute (fpm) to 1,000 fpm, and the flight path angle decreased from 5.8 degrees to 2.7 degrees. The airplane contacted the runway on the main landing gear and bounced, at which time the airplane pitched nose up to about 11 degrees. The tail of the airplane subsequently struck the runway and was substantially damaged. No anomalies with the airplane systems or engines were reported during the investigation. The airline's aircraft operating manual described a 'stabilized approach concept,' but the airline did not provide specific procedures regarding crew actions, or require a go-around, if an approach becomes unstabilized.
NTSB factual narrative text:
On February 6, 1997, at 1440 Atlantic standard time, N4106, an Airbus A300-600R, operated by American Airlines as flight AA699, was damaged on the underside of the lower fuselage when the tail section struck the runway surface during landing at V. C. Bird International Airport in St. Johns, Antigua. The extent of the airplane damage was substantial. The Captain, First Officer, seven flight attendants and 161 passengers were not injured. The flight, a scheduled CFR Part 121 operation from San Juan (SJU) to the Antigua (ANU), was uneventful until the landing event. Visual meteorological conditions prevailed and an Instrument Flight Rules (IFR) flight plan was filed.
In accordance with the International Standards and Recommended Practices of ICAO Annex 13, para 5.1, the state of occurrence, Antigua and Barbuda, in a letter dated February 11, 1997, delegated the accident investigation to the state of registry/operator, the United States of America, and the NTSB is responsible for the investigation and report.
The pilot/operator report dated February 14, 1997, submitted by the American Airlines Senior Administrator Flight Safety stated that the flightcrew reported that the Captain was the flying pilot during a VOR DME Rwy 07 approach to the airport. At about 2,500 feet msl., they maneuvered to avoid TCAS traffic which was visually sighted. At 1,000 feet, on the final approach with the landing runway in sight, the First Officer made the company procedural 1,000 foot verbal callout and the Captain brought the power above idle. The crew reportedly observed the flight to be slightly high at 1,000 feet; by 500 feet the crew felt that airplane was "in the slot" with the airspeed about 20 knots above the reference speed and decreasing. At about 200 feet the First Officer recalled that he advised the Captain that the airspeed was slightly low. In response, the Captain added power. The approach appeared normal to the crew until the automatic aural altitude call out began at 50 feet. The Captain sensed that the timing of the call outs from 30 feet down were slightly faster than normal. The Captain recalled that he initially flared at about 30 feet and reduced power to idle. In an effort to cushion the descent, he "deepened" the landing flare "just prior to touchdown." The touchdown was reported to be "firm" and resulted in a bounced landing. A second touchdown occurred in a higher than normal pitch attitude. A flight attendant reported to the Captain that she heard "a loud noise" upon landing and a post flight inspection revealed that a tail strike had occurred to the underside of the fuselage.
A brief description of the airplane damage provided by the Directorate of Civil Aviation for Eastern Caribbean States indicated 5 belly skin panels scraped through, buckled, and destroyed, all frames and stringers within the damage area buckled or sheared, 3 struts broken and a floor beam twisted. American Airlines specialized maintenance personnel performed a temporary repair in Antigua. An FAA ferry permit was issued and the airplane was flown, unpressurized, to the American Airlines maintenance facility in Tulsa, Oklahoma for complete repair and return to service.
American Airlines crew scheduling information indicated the Captain and First Officer had a scheduled duty period of 9 hours and 20 minutes on the day of the accident. During that period, in addition to the accident flight of about 40minutes, the crew logged 3.0 hours of flying time from JFK to SJU. The crew was not scheduled for duty during the 24 hour day previous to the accident. Prior to that non-duty day, both crew members attended 3 days of ground training.
American Airlines crew records indicated the Captain had over 19,000 hours of flying experience with 4,671 hours in the A300 airplane.
The American Airlines A300 Operating Manual, Techniques section, page 9 dated 8-14-95, contains a diagram describing the Landing Approach. It illustrates an airplane at 15 feet above the runway with a pitch angle of 5.9 degrees nose up. The American Airlines A300 Operating Manual, Techniques section, page 8 dated 8-14-95, contains a paragraph "Stabilized Approach Concept" as follows:
The stabilized approach concept requires that, before descending below the specified minimum stabilized altitude, the airplane should be- * in the landing configuration(gear down and final flaps), * on Approach Speed, * on the proper flight path at the proper sink rate, * and at stabilized thrust.
And these conditions should then be maintained throughout the rest of the approach. The minimum recommended stabilized approach altitudes are: * VFR - 500 ft. AFL * IFR - 1000 ft. AFL
In response to a Safety Board request for the weight and balance data for the accident flight, American Airlines Operations and Load Planning departments provided the following data; Landing weight 275,218 lbs. Landing CG: 27% Vref. Flaps20/139 KIAS; Flaps 40/128 KIAS Vapp. Flaps20/145 KIAS; Flaps 40/134 KIAS
Although American Airlines company procedures require protection of the CVR from automatic erasure/overwrite following an accident, these procedures were not adhered to and the CVR was activated on the ground in Antigua. When the CVR was readout in the Safety Board's laboratory in Washington, D.C., the recorded conversation was found to be from maintenance personnel not pertinent to the accident.
The DFDR was read out in the Safety Board's laboratory in Washington, D.C. The data from the DFDR indicated the following:
At about 1000 feet radio altitude, the computed airspeed was 148 knots, the engines were at minimum thrust (30% RPM), and the pitch attitude was about 2 degrees nose down (sampled once each second).
At about 500 feet radio altitude, the computed airspeed was 143 knots, the engines were at minimum thrust (30% RPM), and the pitch attitude was about 1/2 degree nose up.
At about 100 feet radio altitude, the computed airspeed was 138 knots, the engines were at 50 to 60% RPM, and the pitch attitude was about 4 degrees nose up.
At about 30 feet radio altitude, the computed airspeed was 135 knots, the engines were at about 55% RPM, and the pitch attitude was about 6 degrees nose up.
At about 0 feet radio altitude, the computed airspeed was 124 knots, the engines were at 45 to 50% RPM, the pitch attitude was about 9 degrees nose up, and a vertical acceleration of 1.55 "g" was recorded. Landing gear air/ground indications (left, right, and nose landing gear strut compression sampled once each second), remained in the "air" position for the next 9 seconds.
During the 9 second interval, the radio altitude remained about 0 feet, the computed airspeed remained about 124 knots, the engines accelerated to between 60 and 80% and then decreased to 40 to 50% RPM, the pitch attitude increased to 10.89 degrees nose up, a 2 "g" vertical acceleration was recorded, and the air/ground indications began to indicate "ground."
From the DFDR data, Safety Board performance engineers derived descent rates and flight path angles for the final approach. The calculations show for the 30 seconds prior to air/ground touchdown indications, that the airplane descent rate was from 1700 feet per minute (fpm) decreasing to about 1000 fpm. and the flight path angle was from 5.8 degrees decreasing to 2.7 degrees.
Shortly after the accident the flight crew members involved each received a proficiency check accomplished in the American Airlines training department. These checks were observed by an FAA operations inspector from the certificate management office. The checks were graded satisfactory and the crew members returned to their scheduled line flying duties.
In March 1998, the American Airlines A300 Fleet Support Team published A300 Briefing Bulletin No. 3, "Avoiding Tail Strikes." The context of the bulletin indicated that, "Deviation from normal landing technique is the most common cause of tail strike, especially: -Allowing the speed to decrease well below Vapp. -Holding the airplane off the ground for a smooth landing. -Flare started too high. -Failure to fly the nose gear on to the runway after touchdown.'
The stated purpose of Briefing Bulletin no. 3 was "to provide flight crews with information and operational guidelines concerning the avoidance of tail strikes." A bulletin is not intended to be a procedural document.
On May 1, 1998, The AA A300 Operating Manual, Chapter 10, TECHNIQUES, was modified to include a paragraph titled, "Tail Strike Avoidance." The operating manual change indicated that, "Deviation from normal landing technique remains the most common cause of tail strikes. Specifically: -Allowing Speed to Decrease Well Below Vapp on Short Final. -Holding the Airplane Off the Runway. -Flare Too High. -Failure to Fly the Nose Gear onto the Runway After Touchdown.'
On September 2, 1998, in response to queries from the Safety Board regarding further accident prevention efforts, the American Airlines Flight Safety department sent the following message to the Safety Board relative to the accident with AA flight 699 of February 6, 1997.
American Airlines has expressed to its crews a "no-fault go-around" policy. Phrases such as "If you don't like what's going on or the way things look-get out of town", authored by Captain Cecil Ewell, Vice President of Flight and Chief Pilot are used to communicate this policy to the pilot force via many avenues. We have these iterations in the Flight Deck Magazine, and briefing bulletins on various subjects that express this doctrine.
We are in receipt of a report from the Flight Safety Foundation, dated February-March, 1998, entitled DATA SUPPORT SAFETY ACTIONS RECOMMENDED BY FSF APPROACH-AND-LANDING ACCIDENT REDUCTION TASK FORCE. Paragraph 4 of this report suggests a need for a no-fault go-around policy such as American Airlines has, and further suggests "Companies should declare and support no-fault go-around and missed-approach policies."
In order to best accomplish the declaration of no-fault go-around as our policy, American Airlines will amend its operational manual system to include specific verbiage to communicate this concept as our policy. A decision as to the placement of this verbiage has not yet been made, i.e.; whether to include this in our Flight Manual Part One, the general operations manual, or to include it in each fleet's Airplane Operating Manual. It will be made in such a way that all pilots operating all of our fleet types will understand that no-fault go-around is the policy at American Airlines.
I will keep you advised as this process matures, and provide a copy of the final product as it relates to the A300 fleet for your files.
Thank you for your assistance.
/signed/ Senior Administrator Flight Safety
On August 15, 1999, American Airlines Flight Manual Part 1, for all flightcrew was modified to include the following, "Paragraph 5 Missed Approach, 5.1 General, American Airlines has a no-fault go-around policy, recognizing that a successful approach can end in a missed approach. Captains are required to execute/order a missed approach if the aircraft is not stabilized by 1000 feet AFL(IFR) or 500 feet AFL (VFR), or if in the pilot's judgement a safe landing cannot be accomplished within the touchdown zone, or the aircraft cannot be stopped within the confines of the runway."
Further, American Airlines Flight Operations Technical Information Bulletin Number 99-07, dated September 1999, titled " Landing Tail Strike Avoidance" was distributed to all flightcrew. Also, AA Flight Safety magazine Nov/Dec 1999 issue, published for all flightcrew contained two articles pertaining to this accident, "Avoiding Tailstrikes: Energy Management" and "A Tale of Two Tails".
|Learning Keywords:||Operations - Airspace - TCAS|
|Operations - Tailstrike|
|Operations - Unstabilized Approach|
|Consequence - Damage - Airframe or fuselage|
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