Event Details

Title:TCAS Resolution Advisory injury involving a Boeing 727-200 and NASA T-38A, March 9, 1993
Micro summary:This Boeing 727-200 received a resolution advisory from TCAS during an encounter with a T-38A, seriously injuring a passenger in the aft galley.
Event Time:1993-03-09 at 1400 CST
File Name:1993-03-09-US.pdf
Publishing Agency:National Transportation Safety Board (NTSB)
Publishing Country:USA
Report number:FTW93FA100
Site of event:Houston, TX
Departure:Manuel Crescencio Rej—n International Airport, Mˇrida, Yucat‡n, Mexico
Destination:George Bush Intercontinental Airport, Houston, Texas, USA
Airplane Type(s):Boeing 727-200
Flight Phase:Cruise
Operator(s):Continental Airlines
Type of flight:Revenue
Serious Injuries:1
Other Injuries:0
Executive Summary:

NTSB short summary:

The failure of the pilot of the T-38A to follow flight advisories. A factor which contributed to the accident was the development of a letter of agreement between the FAA and NASA which was not in accordance with ICAO procedures.

NTSB synopsis:

During cruise at flight level 350, while over the Gulf of Mexico, the crew received a climb resolution advisory from the traffic alert and collision avoidance system (TCAS). The crew initiated a climb initially at 1,500 fpm, and then increased the climb to 2,500 fpm. A passenger standing near the aft galley sustained serious injuries. The traffic was a nasa T-38A performing a functional check flight. During the stall series, the T-38A had descended through flight level 350, and the pilot initiated a climb back to above flight level 350. The T-38A was VFR based on a letter of agreement, and the pilot had been advised by ATC not to go below flight level 350 because of numerous traffic in the area. The letter of agreement between houston ARTCC, NASA, Houston Intercontinental tower, and the 147th fighter interceptor group, Ellington Field, Texas, was in violation of extant International Civil Aviation Organization (ICAO) agreements, and was rescinded on 3/10/93, the day following the accident.
NTSB factual narrative text:


On March 9, 1993, at approximately 1400 central standard time, a passenger on Continental Airlines Flight (COA) 1080 sustained serious injury during cruise at flight level 350. The airplane, a Boeing 727 200, N79754, departed from Merida, Mexico, enroute to Houston, Texas, with 38 passengers and a crew of eight. The crew initiated a climb when the Traffic Alert and Collision Avoidance System (TCAS) resolution advisory (RA) indicated traffic closing rapidly. The aircraft did not sustain damage. Visual meteorological conditions prevailed for the international flight.

The traffic airplane was identified as National Aeronautics and Space Administration (NASA) flight 920, a Northrup T 38A airplane. The pilot of NASA 920 was conducting a functional check flight (FCF). Interviews conducted by the investigator in charge with NASA personnel and the pilot revealed the following information. The FCF profile (included as a part of this report) may be accomplished in a sequence established by the pilot, but must include all profile items. During the flight procedure stall sequence, the airplane must be maintained in the stall configuration until a 6,000 foot per minute rate of descent has been reached. (Included as a part of this report is the flight procedures manual for the stall sequence.) The pilot initiated the stall sequence above flight level 350 and completed the maneuver below flight level 350. NASA 920 was operating under a Letter of Agreement between Houston ARTCC and NASA. The agreement permitted NASA airplanes to operate under visual flight rules in international airspace. The agreement was originally signed on August 17, 1989.

During interviews conducted by the investigator in charge (IIC) with company personnel and the controller, the following information was revealed. The flight crew of COA 1080, operating under instrument flight rules, reported on frequency with the controller at approximately 1326 and reported at flight level 350. The pilot of NASA 920, operating under visual flight rules with traffic advisories, had been advised by the controller to stay above flight level 350.

An interview conducted by the investigator in charge with the captain of COA 1080 and the enclosed statements submitted by the COA 1080 flight crew revealed the following information. Traffic at the twelve o'clock position was showing as 7,800 feet below the Boeing 727 200 and closing rapidly. TCAS called for a climb of 1,500 feet per minute. The flight engineer turned on the seat belt sign as the captain and first officer initiated a climb. Initial climb was at 1,500 feet per minute and then increased to 2,500 feet per minute. A flight attendant reported that a passenger had broken her leg. The flight landed without further incident.

The witness reported to the company and the Board that she was standing near the back of the airplane when the "plane engines sounded so loud all of a sudden." She "fell backwards" and was on the floor. The passenger remained on the floor until the airplane had landed.

PERSONNEL INFORMATION: All flight crew members held airline transport pilot certificates and several thousand hours of flight time. The entire COA 1080 flight crew had received recurrent TCAS training in accordance with the approved procedures manual. Company personnel for COA 1080 revealed to the Board that emergency training did not require the crew to report a non life threatening injury to air traffic control.


A review of the air traffic data by the investigator in charge revealed the following summary of transmission between the controller and pilots. All times have been converted to central standard time. The air traffic control group chairman's factual report is enclosed.

1358:10 NASA 920 was advised by the controller that numerous traffic was in the area and that he could not call out each individual traffic. The controller suggested that NASA 920 remain above flight level 350.

1359:09 The controller requested that the pilot of NASA 920 say his altitude.

1359:12 The pilot of NASA 920 reported to the controller that he was at flight level 335 and climbing back up above flight level 350.

1359:15 The controller advised the pilot of NASA 920 to get above flight level 350 and issued traffic as nine o'clock and three miles at flight level 350.

1359:31 The controller issued traffic to COA 1080 as twelve o'clock and three miles a NASA T 38 under visual flight rules climbing rapidly out of flight level 340.

1359:50 The controller advised the pilot of NASA 920 that the traffic was twelve o'clock less than a mile and to verify that the T 38 was "staying at" flight level 340.

1359:56 The pilot of NASA 920 reported to the controller that he was out of flight level 348.

1400:04 The crew of COA 1080 advised the controller that they had responded to a TCAS alert for a climb and had climbed to flight level 358. COA 1080 was cleared to descend to flight level 350 and advised that the NASA 920 was level at flight level 340.


The Safety Board never took possession of the airplane.
Learning Keywords:Operations - Airspace - Air Proximity
Operations - Airspace - Air Traffic Control
Operations - Airspace - TCAS


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