The US National Transportation Safety Board is investigating an Embraer Phenom 100 landing incident that occurred in Texas on 10 September, marking an official safety inquiry into a series of brake-by-wire system issues that have occurred with Embraer's entry-level jet.
The pilot and passenger on board the six-seater twinjet (N226CP) were landing at the Brenham Municipal airport for fuel in good weather that afternoon when they received a warning light indicating the brake system was not working, an airport official says. Brake failure procedures instruct pilots to multiply the full-flap landing distance by 1.5 and to "progressively" pull the aircraft's manual parking/emergency brake handle, located in the centre console between the pilots' seats. Embraer notes that the emergency brake accumulator "allows for six actuations".
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As in several previous events however, including a landing incident in Mammoth Valley, California in March, the main gear wheels appear to have locked up and blown the tyres during the emergency brake application despite specific training put in place to prevent flats.
Embraer's efforts to understand the brake system issues have focused on several possible problems with the brake-by-wire design, including the brake control computer system that senses pedal pressure and commands the brakes, and the potential for having air in the hydraulic lines. Embraer has issued an improved procedure for bleeding brake lines and has a service bulletin out for a new brake control unit. It is not clear what upgrades had been installed on N226CP.
In the Texas incident, witnesses say the pilot maintained directional control about halfway down the 1,800m (6,000ft) runway after landing before partially exiting the side of the runway, damaging a landing gear strut and wing light in the process. The occupants were not injured.
The runway remained closed for two days until the aircraft was moved to a parking area for Embraer officials to examine it. As of 21 September, the Phenom 100 remained at the airport on chocks as the NTSB continued its investigation.
Embraer says it is supporting the NSTB effort as an advisor to the Brazilian safety agency Cenipa.
Source: Flight International
