# NTSB DCA03IA005: Boeing 757-200, Baltimore, MD, October 20, 2002 - Type: NTSB incident investigation - Classification: Incident · No injuries · Incident investigation · Final report - Date: October 20, 2002, 00:30 UTC - Place: Baltimore, MD - Coordinates: 39.289756, -76.61959 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.2898&lon=-76.6196&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 196 uninjured - Status: Completed, report July 15, 2005 - Report: Approved by Office Director - NTSB office: Major Investigations Division - ADs cited in the narratives: [AD 2004-10-15](https://openairdocs.org/ad/2004-10-15) (OpenAirDocs) - NTSB case key (mKey): 55902 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA03IA005 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55902/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55902 - Page: https://openairdocs.org/ntsb/DCA03IA005 ## Probable cause The captain's improper procedures regarding stall avoidance and recovery. Contributing to the incident were the partial blockage of the pitot static system, and the flight crew's improper decisions regarding their use of inaccurate airspeed indications. Contributing to the flight crew's confusion during the flight were the indistinct alerts generated by the airplane's crew alerting system. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - roll/run - pitot/static system - blocked(partial) - Airframe/component/system failure/malfunction, climb - to cruise - pitot/static system - blocked(partial) (contributing factor) - flight/nav instruments,airspeed indicator - false indication (contributing factor) - Loss of control - in flight, cruise - in-flight planning/decision - improper, flightcrew (contributing factor) - airspeed - not maintained, pilot in command (cause) - stall - improper use of procedure, pilot in command (cause) ## Analysis During the takeoff roll as the captain was about to call "eighty" knots, the first officer called "hundred." The captain noted that the standby airspeed indicator agreed with the first officer's and decided to continue the takeoff and address the anomaly of his airspeed indicator after takeoff. The pilots indicated that EICAS messages appeared and disappeared several times after takeoff and during the climb, including the messages MACH/SPD TRIM and RUDDER RATIO. Checklists for MACH/SPD TRIM and RUDDER RATIO messages did not mention an unreliable airspeed as a possible condition. The modifications associated with Boeing Alert Service Bulletin 757-34A0222 (and mandated by FAA Airworthiness Directive 2004-10-15 after the incident), which had not been incorporated on the incident airplane, would have provided a more direct indication of the airspeed anomaly. According to information in the Icelandair Operations Manual, these EICAS messages (in conjunction with disagreements between the captain and first officer airspeed indicators) may indicate an unreliable airspeed. Overspeed indications and simultaneous overspeed and stall warnings (both of which occurred during the airplane's climb from FL330 to FL370) are also cited as further indications of a possible unreliable airspeed. The crew did take actions in an attempt to isolate the anomalies (such as switching from the center autopilot to the right autopilot at one point during the flight). However, this did not affect the flight management computer's use of data from the left (captain's) air data system, and the erroneous high airspeeds subsequently contributed to airplane-nose-up autopilot commands during and after the airplane's climb to FL370. During the climb the captain's indicated airspeed began to increase, and the overspeed warning occurred. The first officer indicated that at this time his airspeed indication and the standby airspeed indication both decreased to about 220 knots and his pitch attitude felt high. Despite agreement between the first officer and standby airspeed indications and the pilots' belief that the captain's airspeed indicator was inaccurate, control was transferred from the first officer to the captain. Pitch attitude continued to climb and airspeed continued to decay after the captain assumed control. The airplane's pitch attitude became excessively high until the airplane's stick shaker activated and the airplane stalled. Although stall recovery was eventually effected and the airplane was leveled at FL300, the lack of appropriate thrust and control column inputs following the stall delayed the recovery. Evidence from the investigation indicates that anomalies of the captain's airspeed indicator were caused by a partial and intermittent blockage of the captain's pitot tube. The reason for the blockage was not determined. ## Factual narrative HISTORY OF FLIGHT On October 19, 2002, about 2000 eastern daylight time (EDT) [or 0000 coordinated universal time (UTC)], a Boeing 757-200, TF-FII, operating as Icelandair flight 662, experienced a stall while climbing from flight level (FL) 330 (i.e., 33,000 feet) to FL 370. The flight lost about 7,000 feet during the recovery and then diverted to Baltimore-Washington International Airport (BWI), Baltimore, Maryland. There were no injuries to the 191 passengers or 7 crewmembers and no damage to the airplane. The airplane was being operated under the provisions of 14 Code of Federal Regulations Part 129 as a scheduled international passenger flight from Orlando International Airport (MCO), Orlando, Florida, to Keflavik International Airport, Keflavik, Iceland (KEF). The incident flight departed MCO about 1900 EDT; the first officer was the pilot flying (PF). According to Icelandair's Standard Operating Procedures (SOPs) and Boeing's 757/767 Flight Crew Training Manual, the captain (as the non-flying pilot) was responsible for calling out 80 knots during the takeoff roll. The captain indicated that about the time he was going to call out 80 knots, the first officer called out 100 knots. The captain indicated that he was going to abort the takeoff until he noticed that the first officer and the standby airspeed indicators were indicating the same airspeed (at this point, about 110 knots). He decided to allow the FO to continue with the takeoff, with the option of returning to MCO. The first officer indicated that during the takeoff, all of the parameters on his side were normal; therefore, he continued the takeoff. The pilots indicated that shortly after takeoff, the lateral and vertical flight director (FD) bars on the captain's display and lateral FD bar on the first officer's display disappeared. The first officer switched his flight director source from "right" to "center", but the problem remained and the first officer returned the switch to "right". In addition, after passing through about 1,000 feet, the advisory messages MACH/SPD TRIM and RUDDER RATIO appeared on the Engine Indication and Crew Alerting System (EICAS) display. The status message ELEV ASYM also displayed. (EICAS information includes systems alerts, maintenance information, and status messages.) The captain told the first officer to continue the climb and to deal with the messages later. After trimming the airplane and retracting the flaps, the first officer asked the captain for the After-Takeoff checklist and the Quick Reference Handbook (QRH) to address the EICAS messages. Subsequently, the EICAS messages disappeared, the FD bars returned, and the airspeed indications showed consistent readings. After climbing through about 10,000 feet, the same advisory and status messages again appeared on the EICAS, and the captain airspeed indication showed 10 knots lower than the first officer and the standby airspeed indications. A few minutes later, the EICAS messages disappeared, and the captain's airspeed indication again agreed with the first officer and the standby airspeed indications. The first officer indicated that the messages disappeared without any action by the flight crew. When the flight reached FL 330, the same messages and airspeed sequences once again occurred, and then everything returned to normal about two minutes later. The pilots indicated that they suspected that failure in the left Air Data Computer might have caused the captain's airspeed anomalies. However, they indicated that because no failure flags appeared on the captain's airspeed indicator, they decided not to switch captain's air data source to alternate. After a little over an hour into the flight, air traffic control (ATC) authorized a climb to FL 370. The climb from FL 330 was made at normal climb power, with the autothrottle and the autopilot engaged. During the climb the captain's indicated airspeed began increasing, and the overspeed warning occurred as the airplane neared FL 350. The first officer indicated that he did not remember what his airspeed indication was at that time. The pilots indicated that because of the previous airspeed anomalies, they felt that the overspeed warning was erroneous and they decided to pull circuit breakers to silence the aural overspeed warning. The captain stated that his airspeed indication reached a maximum of between 320 and 350 knots during the climb. The first officer indicated that during the climb his airspeed indication and the standby airspeed indication both decreased from about 250 to 220 knots. The first officer told the captain that he did not think that his airspeed indication was reliable and asked him to take control of the airplane. He stated that the captain promptly took control of the airplane. The first officer indicated that he did not remember the pitch attitude at this time but thought that it was less than 10 degrees. When asked why control was transferred from the first officer to the captain, despite their acknowledgement of anomalies with the captain's airspeed indicator and agreement between the first officer and standby airspeed indicators, the first officer indicated that he noticed that the airplane's pitch was unusually high and the airspeed had decreased substantially. Because he became unconvinced whether his instruments were correct, he asked the captain to assume control of the airplane. The captain indicated that he had a better view of the standby instruments, in case the first officer's airspeed indicator had become unreliable. Soon after the captain assumed control, the flight experienced activation of the stick shaker and then heavy stall buffet. The captain indicated that he then disconnected the autopilot and autothrottle. The captain indicated that he initiated the stall recovery by reducing the power to idle and lowering the nose about 5 degrees below the horizon. He indicated that he looked at the first officer and standby airspeed indications and that they were the same. The captain stated that "there was a lot of vibration" during the stall encounter, and both pilots acknowledged that they had never experienced anything like it before. The first officer indicated that the stall buffet felt a little bit different than what he had experienced during simulator training but that it felt the same in strength. Subsequent FDR analysis revealed that the stick-shaker continued for about 45 seconds. During the loss of altitude, the first officer radioed the urgency message PAN PAN, advising that they were unable to maintain altitude and were descending out of their cleared flight level. The flight crew received immediate clearance to descend FL 300 and then subsequently to FL 290. The captain then decided to divert to BWI. The pilots stated that they monitored their instruments during the descent to BWI. The captain indicated that his airspeed indication was 40 to 70 knots lower than the first officer and standby airspeed indications at times during the descent. After descending to FL 250, the pilots verified that the first officer and standby airspeed indications were the same (about 250 knots), and the first officer took control of the airplane and reengaged the autopilot. The captain indicated that at this time, his airspeed indication was 180 knots. The pilots further checked the captain's airspeed indication against ground speed values provided by ATC to determine the erroneous nature of the airspeed indication. The flight landed at BWI about 2100 EDT. PERSONNEL INFORMATION Captain The captain has been employed by Icelandair since 1986. His total flight time prior to the incident was around 8,500 hours, including about 1,020 hours as B-757 pilot-in-command (PIC). He previously served as captain with Icelandair on the Fokker 50 and as first officer on the B-757. The captain completed training (as a captain) for his B-757 t ## Aircraft - Registration: TF-FII (not matched to a registry record) - Reported make and model: Boeing 757-200 - Category: Airplane - Serial number: 24760 - Engines: Rolls-Royce RB211-535E4 turbo fan - Damage: No damage - Flight: Part 129 - Operator: Icelandair - Fkygkeudur Hf - Registered owner: CIT Aerospace - Airworthiness certificate: Standard, Normal - Departed: Orlando, FL - Destination: Keflavik - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; injuries: none; airline transport; medical: class 1; seat: left; flight hours: 8,500 total - Co-pilot; age 35; injuries: none; medical: class 1; seat: right; flight hours: 4,100 total, 1,800 in this make and model ## Docket (3 files) The files NTSB released with the investigation on July 8, 2005, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55902. 1.5 MB in all. - FAA ADC Letter (item 1, .PDF, 26 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40448952&FileExtension=.PDF&FileName=FAA%20ADC%20Letter-Master.PDF - Boeing SB 757-34A0222 Rev 2---Summary (item 2, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40232589&FileExtension=.PDF&FileName=Boeing%20SB%20757-34A0222%20Rev%202---Summary-Master.PDF - Boeing plots (item 3, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40234979&FileExtension=.PDF&FileName=Boeing%20plots-Master.PDF From the NTSB's public API. 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