A few years ago, two other pilots and I decided to make a trip from Seattle to Oregon for a fly-in. Each pilot would be a separate airplane with passengers. I was flying a Cessna 172 with my son as the only passenger with me. Two aircraft were leaving Renton Municipal Airport with the third joining us enroute. The destination was Hood River in Oregon.
Our route would take us in a fairly straight line with a path that would lie between Mt. St Helens and Mt. Rainier. This meant flying over some mountainous terrain, albeit under 10,000 feet. We also elected to use flight following on the way down. Being a pilot who had under 80 hours at the time, I was aware of flight following and had no issues with the procedures and hand-offs the entire way.
After spending time at the Hood River fly-in and deciding it was time to head back home so the airplane was available for the next renter, I started my pre-flight on the aircraft. When dipping the tanks, I noted that one tank was about half full and the other tank was closer to three-fourths full. At that point, I realized that I had neglected to lean the engine during the flight down, likely due to the added task of flight following and discussions with my son about the crater and the Mt. St. Helens eruption. A rookie mistake for sure, but I had fuel for the remaining trip back because I planned to lean the engine once at altitude.
On the takeoff roll, I noted that we need most of the runway to get airborne. Mental note to self at the time that I should have recalculated the density altitude. The local temperature was higher than forecast so I should have taken that into consideration. However, we were airborne and on our way.
The return route was intended to mirror the route we had taken down so I was heading west along the Columbia river, watching for other aircraft and getting ready for my turn north, which would require climbing to get above the rocky elevations. As we started the inland portion, I noted that the aircraft was only climbing at 50 feet per minute. I was a bit surprised, as the specific 172 I was in had been equipped with a climb prop by the flying club that owned it. Again, the density altitude was playing into the performance as it had during takeoff.
Knowing that I would not achieve the required altitude to fly over the rocky regions for my return flight, I elected to do climbing spirals to gain the altitude. With only 50 fpm or less over land, I wondered if the Columbia River would offer some change in air density due to the water temperature being a bit cooler than land temperature. So we did the climbing spiral over the river, which netted me 25 to 50 fpm more in climb performance
Once I reached my target altitude, I started north along the route of return and began focusing on trimming the airplane and leaning the engine. The fuel gauges had been consistent with what I expected on fuel burn during our climb. I knew that the circling would burn through more than planned originally, but the gauges still seemed to be offering me peace of mind that I was ok on fuel, until we reached the point directly between Mt. St. Helens and Mt. Rainier. Then the left gauge started bouncing between empty and one quarter tank and the right gauge bouncing between one half and one quarter full. How much fuel do I actually have? Why is that left tank going down faster than the left? What happens if it runs out first? Will the fuel still feed from the right without interruption?
For the first time, I was truly concerned about my safety, and that of my son, in an airplane. How had I let myself get in this situation? What are my options? Will I become a statistic? Looking down at the terrain below me, I know there are no “good” places to set an airplane down that has just run out of fuel. Should I turn around and go back to Hood River? No, I was a little more than half way home but regardless, even if I filled up at Hood River, based on my previous takeoff, I likely wouldn’t get off the runway with the added load of full fuel. What were my options?
This flight took place before we had EFB capabilities on the iPad through ForeFlight or Garmin Pilot, but the 172 I was flying did have a Garmin 430. Having spent time with Garmin simulators and having taken training for the Garmin G1000, I was aware of the capabilities of these units. I immediately went to the NRST function on the GPS and started to cycle trough the airports, looking for one that had fuel. KPLU popped up showing self-service fuel and it was only 20 miles away. That’s when I punched the Direct To button and changed course.
We landed at KPLU without incident and with fuel to spare. After filling up the tanks, I did some calculations on capacity and fuel burn and realized that the gauges were not being kind to me at all. Ultimately, I would have had sufficient fuel to reach KRNT, although my reserve might have been less than the required 30 minutes.
Here’s what I know for certain that I did wrong:
- Inadequate flight planning that allowed for conditions beyond forecast (density altitude had changed while I was en route and at Hood River)
- Did not lean the engine for flight at altitude on the trip down (in hindsight, would this have resulted in a takeoff problem at Hood River with additional fuel?)
- Did not perform a density altitude calculation at Hood River to determine flight performance before takeoff and return trip.
What did I do right?
- Used the capabilities of the aircraft and equipment I was flying
- Learned about the technology and equipment that was in the airplane so I was familiar with its capabilities and how to effectively use it
- Continued to work the problem. I did not resign myself to failure nor did I let my bad decisions impact my ability to analyze the situation and work a solution
- Took immediate action to address the problem and therefore broke the accident chain
Ultimately, the experience led me to take time away from flying as I evaluated my desire to fly and my abilities. I took a full two years off before I went back to it. Before I did fly again, I sat with my original CFI and discussed the incident and my thoughts. After good feedback and discussion from him, we hopped in a plane and did some solid flight review to knock off the rust, build the confidence back again, and truly enjoy the experience of flight.