History of the Flight
The aircraft, a Boeing 737-204 Advanced registered EI-CJH, was conducting a scheduled passenger service from Dublin, Ireland, to Manchester, England. The flight crew consisted of a training captain occupying the right seat and a command trainee pilot in the left seat; the training captain was the handling pilot. The aircraft departed Dublin with the outboard anti-skid system inoperative, in accordance with the Minimum Equipment List (MEL).
Weather conditions at Manchester were fine, with wind from 060° at 5 knots, good visibility, and no significant cloud or weather. Approximately seven miles from touchdown on Runway 24R, the crew selected flap 15° and armed the speedbrake for automatic spoiler deployment on the ground. Immediately after arming, the SPEEDBRAKE DO NOT ARM warning light illuminated. The crew responded by returning the speedbrake lever to the DOWN position and briefed for manual spoiler deployment after landing.
The touchdown was smooth. The handling pilot lowered the nosewheel, selected reverse thrust, moved the speedbrake lever to the UP position, and applied gentle braking. As the speedbrakes deployed, the left main undercarriage inboard tyre burst, accompanied by a slight left swing. While the aircraft approached the runway turnoff, the outboard tyre on the left main undercarriage also burst, causing a more dramatic left slew. The handling pilot transferred control to the left seat pilot, who used the nose gear steering wheel to attempt a right turn onto taxiway BD. With difficulty, the trainee captain guided the aircraft off the runway and brought it to a halt on BD. After ATC confirmed no signs of fire, the crew decided against an emergency passenger evacuation and shut down the engines on the taxiway.
Aircraft and Crew
The Boeing 737-204 Advanced (year of manufacture 1980) was powered by two Pratt & Whitney JT8D-15 turbofan engines. There were 5 crew and 33 passengers on board; no injuries were sustained. The commander held an Airline Transport Pilot's Licence, was 49 years old, and had accumulated 9,800 total flying hours, including 6,800 hours on type. His recent flying experience included 190 hours in the last 90 days and 50 hours in the last 28 days.
MEL and Anti-Skid System
The Boeing 737-200 series anti-skid system is controlled by two switches on the pilots' forward instrument panel. One switch controls anti-skid for both inboard main wheels, while the other controls both outboard main wheels. The MEL permits dispatch with the entire anti-skid system inoperative, provided operations comply with the Aircraft Flight Manual (AFM).
Aircraft Examination
Following the incident, the operating company performed comprehensive checks, including assessments for brake seizure, hard landing, high drag/sideload, high energy stop, and tread loss/tyre burst. Before returning the aircraft to service, the No 1 and No 2 wheels and brake units, the left brake metering valve, and the left inboard anti-skid control valve were replaced. A full check of the anti-skid and automatic brake systems was also conducted.
The brake metering valve was returned to its manufacturer for testing; no significant faults were found. The anti-skid control valve was also sent to its manufacturer; the strip report indicated that the unit was defective and could have caused the left inboard wheel to lock. The aircraft manufacturer noted that a fault in the left inboard anti-skid circuit could have prevented the release of hydraulic pressure to the left inboard brake when a skid was detected. It was considered that the left outboard tyre burst as a result of supporting double its normal load after the inner tyre failed, while the outboard anti-skid system remained inoperative.