PA-31 Navajo/Chieftan/Mojave/T1040
Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 50; Flight Crew Total 2450; Flight Crew Type 60
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Weather
It was the third leg of the day on a Part 91 passenger flight with a single passenger on board; who was sitting in the right front (co-pilot) seat. I was flying from the left seat; single-pilot. After two uneventful flights I started the airplane to begin the last leg. During the taxi to the runway I noticed it took more power than normal to taxi; but I attributed it to the fact that the airplane was heavy due to taking on fuel; we were taxiing slightly uphill; and there was some snow/slush contamination on the taxiway. The takeoff seemed normal; as did the rest of the flight until we began the descent.I received the local ASOS information; which reported winds variable at 6 knots; visibility at least 10 statute miles; clear skies; temperature -4 Celsius; dew point -24 Celsius; and altimeter setting of 30.32. Given there was no other traffic in the area; I elected to land on runway X. During the descent I performed a brake check. On the first attempt at the brake check; the left brake felt relatively normal; but the right brake was noticeably 'squishier' than usual. I tried the brake check one more time and this time both brakes felt normal so I continued with the approach and landing. I touched down approximately 1100 ft down the 5500 ft runway. Our calculated landing distance at a 6050 lbs gross weight with a 0.3% downslope; -4 degrees Celsius temperature; and no wind was approximately 1600 ft; well within the remaining runway. When I touched down I applied pressure to the brake pedals and they felt somewhat less effective than normal. There was resistance in the pedals; but it felt as if the brake pads weren't 'grabbing.' The right pedal in particular felt like it did not have any 'give' to it. There was no pedal travel on the right side and very little on the left side. I applied more even pressure and the airplane began to veer left of centerline. I let off pressure on the pedals; reestablished myself on the centerline; and then tried again. Again the airplane veered left. At this point I was not comfortable performing a go-around considering the lack of remaining runway; configuration changes that would be needed; and high terrain at the end of the runway. In hindsight; however; that may have been the better option. I applied maximum braking effort; using right rudder to counteract the tendency of the airplane to pull left. With only about two hundred feet of runway remaining I asked my passenger to assist me on the brakes. With both of us 'standing' on the brakes we managed to lock up the left side and bring the airplane to a stop less than 20 feet from the end of the runway.A local mechanic performed an inspection of the brake system and determined the likely culprit was water in the brake fluid that had frozen in the 6+ hours we had been airborne that day. The source of the water is undetermined. The corrective maintenance has yet to be performed; but the plan is to allow the airplane to thaw for an extended period of time in a heated hangar; to drain the brake system of fluid; then refill it with new fluid. In the future if I notice the taxi taking more power than usual I will be sure to perform a brake test and/or call maintenance prior to departing.
PA-31 pilot experiences brake failure during landing and requires the assistance of his passenger to stop the aircraft before the end of the runway. Water in the brake fluid and very cold temperatures are suspected as the cause.