Merlin’s magic: unintended fireworks from a P-51

After receiving takeoff clearance from the control tower, I taxied out onto runway 30L at the San Jose (California) Municipal Airport. I lined up on the centerline and advanced the throttle. The aircraft accelerated rapidly and broke ground. This was my fifth solo takeoff in this aircraft, a North American P-51D Mustang. I raised the landing gear, and the climb speed reached about 175 knots. Approaching the airport boundary, the engine began shuddering and vibrating.

I knew I had a serious problem. The vibration became intense and the engine sounded like it was trying to self-destruct. I instinctively pulled back on the throttle, which helped reduce the vibration. But at the reduced throttle setting, there was not enough power to sustain level flight and the terrain immediately beyond the runway was not promising for a forced landing. I decided to trade speed for altitude and try to fly the traffic pattern to return for landing. I immediately executed two 90 degree turns to the right for a close-in right downwind. I announced my intentions to the control tower and they cleared me to land on runway 30R. Using my excess speed, I managed to reach an altitude of about 500 ft. AGL, after which the airplane began a steady descent. The control tower was aware of my plight, and asked me if I wanted to declare an emergency. For some reason, I declined.

Every pilot wants a P-51 checkout.

The P-51 was owned and operated by the California Warbirds flying club, which at the time consisted of about 35 members. The club was originally formed as the Oakland Air Force in 1969. We also owned a North American AT-6, used primarily for transition training for the P-51. My solo checkout in the airplane came only two days before the above incident. Like most stock P-51D models, there was only a single set of controls. There were no provisions for dual instruction in the P-51, which brought to mind the thousands of pilots in their late teens and early twenties who flew this plane into combat with a lot less flying time than I had.

By our club rules, the first flight in the P-51 had to be preceded by a minimum of 40 hours in the AT-6, culminating in a successful checkride from the back seat of the AT-6, followed by a very thorough ground session conducted by one of the club instructors. Only then was the member considered ready to fly the P-51. On August 27, 1976, at the Half Moon Bay, California airport, I was ready, and I successfully completed two solo flights that day, logging about 1.5 hours of flight time and four takeoffs and landings.

Our P-51 had a jump seat installed behind the pilot. Ironically, I had made an emergency landing as a passenger in this same airplane about a year before. On that occasion, I was offered a ride with another club member at the controls. Hank (not his real name) was a fairly low-time pilot, but one of the more active P-51 drivers in the club. What he lacked in experience, he made up for in enthusiasm. Actually his flying was pretty good, and as it turned out, in the end, Hank saved the day.

I should mention that accepting the ride violated one of my personal resolutions about flying, which was to never be without a set of controls in front of me. I suppose this was really a phobia, which stemmed from an accident I was involved in as a passenger more than ten years previously. But, in this case, there were mitigating circumstances. This was a P-51 and the opportunity didn’t come around too often. So on this occasion, I found myself in the back seat, with as much control over my fate as a 150-pound sack of potatoes.

Did we plan on formation flying today?

We were heading from Tracy to Lincoln, California, where we were going to attend a fly-in and air show. The plan was to fly loose formation with a B-25 owned by some of the other club members. Keep in mind: we had no formation training program, briefings, or any other semblance of safe flying practices regarding formation flying. Hank hurried his pre-flight inspection to allow us to rendezvous with the B-25. The planned formation flight became more of a collision-avoidance exercise. Hank seemed oblivious to any threat posed by the wing of the B-25 which was bobbing and weaving a few feet away from our cockpit. Finally, he broke off, widened the gap, and performed the piece de resistance, a well-executed barrel roll. The roll went nicely, except for the sudden appearance of oil on the windscreen. Oil on the windscreen is right up there close to the top of every pilot’s “pray this doesn’t happen” list.

Hank handled the situation well and brought it to a successful conclusion by performing an emergency landing at the Sacramento Executive airport. It should be noted that when you land a P-51 at any airport, you usually have the utmost in help and cooperation. Everybody loves a P-51. The local maintenance facility was happy to lend space, cleaning solution, and a compressor and spray tools to allow cleaning up the oil. Hank removed the cowling and got to work. The source of the problem became quickly apparent. Hank had forgotten to replace the cap on the oil tank during his pre-flight inspection. The barrel roll caused oil to gush out the top of the tank, and as all pilots know, a little oil goes a long way.

I was busy mulling over the situation and after due consideration, I decided to forgo further flight as back-seat baggage in the P-51. I called a friend to come and pick me up. I felt bad informing Hank of this vote of no-confidence, but he seemed to understand. I didn’t mention my phobia.

Riding in an airplane with no controls makes some pilots very uncomfortable.

Thus my resolution was once again set firmly in place, and to this day I can count on one hand the number of times I have flown in light aircraft without being PIC or at least having a set of controls within reach. But I wonder if I might be living in a Fool’s Paradise? Over time, I have proven to myself that I am perfectly capable of making my own stupid mistakes in an airplane. There is a saying in aviation that goes something like this: “Good judgment comes from experience, but unfortunately the experience usually comes from bad judgment.”

Today, the FAA places special emphasis on risk management, which has become an integral part of general aviation training and flight operations. Risk management doesn’t eliminate risk. It attempts to mitigate it by introducing a culture of sound decision-making skills. But even when risk management is perfectly executed, we are left with a set of possible factors that are largely consigned to luck. Luck is something we don’t like to talk about too much, but it is always there lurking in the background. It could be good luck or bad luck, separate and independent, or walking along arm-in-arm. It’s bad luck if your engine quits, but it’s good luck if you have enough remaining runway to land. Once you pass the airport boundary, it’s usually bad luck all the way.

The incident that occurred on the way to Lincoln and the subsequent emergency landing at Sacramento were clearly related to flying skill and judgment, some good, some bad. The situation would have been a perfect candidate for the application of effective risk management principles. But the one that I was presently dealing with, downwind at 500 feet and losing altitude with a failing engine, was pure and simple bad luck. The question was: could I garner enough good luck to put the ledger back in my favor? There were a couple more surprises awaiting me.

Runway 30R at SJC was about 5000 ft. long. There were a few rows of aircraft shelters on the approach path fairly close to the runway threshold. The final approach to Runway 30R crossed a freeway close to the boundary of the airport. If I kept my approach tight, I could hopefully use the altitude I had to clear these obstacles and position myself for a landing.

When I was getting ready to solo the P-51, I spent a few hours sitting in the cockpit, memorizing the location of every switch and control. Back in the old days, this was referred to as the “blindfold cockpit check.” It had benefits for the young pilots who flew combat aircraft. Instead of groping around inside the cockpit, they could concentrate their attention outside the aircraft, where the action was taking place. Our club used the same technique. If it worked for them, it would work for us, even though no one would be shooting at us. For me it was time well spent, and I grew very familiar with the cockpit layout. This was to be of great benefit.

Keeping it as close-in as possible, I turned right base and kept the turn going onto final approach. At this point, I nudged the throttle forward slightly hoping that it would provide a little more power to clear the obstacles. Instead, it responded with a resounding explosion, followed by a period of silence with the prop windmilling. Within a second or two, the RPM picked up, then another explosion. This process was repeated a few times.

What happened to the mighty Merlin engine?

When I saw that I would make the runway, I lowered the landing gear and flaps and closed the throttle completely. The engine amazingly settled down to a fast idle. With a few extra knots of airspeed, I planted the airplane on the numbers in one of the best wheel landings that I have ever made, cleared the runway and rolled to a stop. An excited ground crewman came to tell me about the fireworks display on final approach. Each explosion had produced a spectacular burst of flame and a few parts from the lower cowling. The explosions and parts were from the induction system. The lower cowling was dangling by a couple of fasteners. Thankfully, my luck had held.

For the technically inclined, here’s the interesting part. The P-51 uses the Rolls Royce designed Merlin engine, which is a V-12 with dual overhead cams. Post-mortem examination revealed that the left camshaft had broken just aft of the first cylinder. Thus at least five cylinders on the left were essentially dead weight. The renegade first cylinder was causing the ignition and explosion of the fuel/air mixture in the intake induction system.

I am thankful that this episode ended on a happy note, although it is not an experience that I would want to repeat. Shortly after this flight, I was transferred to Hawaii and had to sell my share in the club. I’m happy to report that the airplane is still flying. The club morphed into a flying museum and can be found at CaliforniaWarbirds.org. As for me, I’m still learning and practicing risk management skills in the RV-7 that my wife and I built.

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Ken Howell

Ken Howell first soloed in 1957 in an Aeronca 7AC. After leaving the Air Force in 1960 he obtained his Private Pilot license and began to work on his advanced ratings. In the next four years he gained his Commercial, CFI, Multi-engine and Instrument ratings and started his life-time avocation as a part time Flight Instructor. He added his Multi-engine Instructor and ATP ratings in 1977. In addition to flight instructing he has flown Part 135 Charter and Corporate Operations. He also holds Private Pilot licenses in Germany, the UK and Australia. Ken always had an interest in warbirds and has had the opportunity to fly the Vultee BT-13, Ryan PT-22, and the North American AT-6 and P-51D.

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