A LR35 departed the runway after weathervaning on a runway poorly drained following a passing thunderstorm and continued light rain. The aircraft's drag chute was deployed and momentarily helped direction control.
Synopsis
A LR35 departed the runway after weathervaning on a runway poorly drained following a passing thunderstorm and continued light rain. The aircraft's drag chute was deployed and momentarily helped direction control.
Narrative
Upon landing at a REF speed of 115 KTS; on centerline; and on the numbers; the aircraft appeared to be operating normally until the first brake application was attempted. Brakes appeared to be non-effective; aircraft began to weathervane into the wind (wind; 200/10kts. on Runway XX); and drift to the right. At approximately 100 KTS; the pilot flying called for the 'chute;' I deployed the drag chute; which straightened the plane out again. However; the plane began to weathervane into the wind again and continued to drift right. Brakes were still completely ineffective. At approximately 70 KTS aircraft departed the right side of the runway with about a 30-degree left crab angle. Aircraft continued for about 100 yards before coming to a stop back on taxiway Golf. Official cause of the incident was hydroplaning. Although weather at the time of landing was light rain; a severe thunderstorm had just passed through the area. The runway surface was flat with no easy way for water to run off. I recommend the airport re-surface the runway with a surface shape (including grooving) that allows for better water run off. No injuries occurred; and no major aircraft damage seen.
Second reporter narrative
After shut down; we performed a very good visual inspection and recommended that the four main tires be changed due to the many flat spots; abrasions and cuts on the tread of the tires. No further damage was found on any part of the aircraft. Nobody was injured; and the Airport Authority did not require any statements. The Airport Authority also stated that there was no damage to the runway or the runway lighting system.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.