Checklist: Troubleshooting With A Camera

A cockpit window mounted GoPro camera, with tie wraps. Photo credit: James Albright 

Although I started flying professionally in the late 1970s, I was flying aircraft built in the 1950s and 1960s. Our ability to troubleshoot aircraft problems depended entirely on our skills of observation and our abilities to effectively explain what we saw to those who would be doing the maintenance. More often than we liked, our efforts were rewarded with a three-letter maintenance sign off: CND, “Could Not Duplicate.” Modern cockpits are filled with computers to record, diagnose, and recommend; but these computers still do not see all or know all.  But allow me to tell a war story about flying some ancient machinery before we go forward.

Years ago in a Gulfstream III, I came back from a flight where one of the partial glass displays did something weird, it completely blanked and then two letters, a "D" and a "U", appeared as big as the screen. There was a possible “display unit” screen message, but it was no taller than half an inch. I called Gulfstream and they refused to believe it. "That can't happen." This was 1992 and there may have been digital cameras out there, but I certainly didn't have one. But as soon as I could afford one, I got one.  And that has made all the difference.

A few years before my GIII incident I had a few in the Boeing 707 that could have cost us an airplane with about thirty people on board. Let's use that as a starting point and press on to how a camera can help you troubleshoot an elusive airplane problem.

Air Force EC-135J at Pima Air Museum. Photo credit: James Albright 

In 1985 I was a fairly new aircraft commander in an Air Force Boeing 707 (EC-135J) based out of Hickam Air Force Base in Hawaii.  (The photo shows the airplane at its final resting place in the Pima Air Museum, near Tucson, Arizona.) One of our standard missions was to takeoff at maximum gross weight with a full load of passengers, heading for the Philippines. On one of these trips, the number three engine fire light illuminated. I shut down the engine, turned around and returned home.

For this episode, everyone was happy we made it back in one piece, but my hero status lasted less than a day, because maintenance said there was nothing wrong with the engine. A more senior crew hopped in the jet, fired up all four, and flew a training mission of five hours. In fact, the airplane flew a regular schedule of local training missions for the next month with nary a hiccup from that engine. I went from hero to zero in the blink of an eye.

About two months after the original episode, I was flying the same airplane headed for the same destination with a different crew but the same set of passengers when the number three engine fire light lit up again. "Shut it down," I said. "Really?" asked the copilot. "Yes." We came home again, this time with some very upset passengers.  After maintenance pronounced the engine healthy with the infamous, three-letter return to service write up, CND, the squadron commander hit the roof and therein began the great "By the book" debate of 1985.

A page from an old Air Force flight manual. Photo credit: James Albright

Our engines had simple fire loops with no fault detection system to tell us if the system was working properly.  More importantly, we didn't have any fire extinguishers and the book left us no choice but to shut the engine down. I think the squadron divided itself into two camps, half of us saying the book meant what the book said, the other half saying we were issued superior judgment for a reason. As the airplane logged a dozen more trouble-free local training missions, the superior judgment crowd was emboldened. 

As the weeks went by, I chided myself for not taking better notes before shutting the engine down. I should have recorded the readings from all four engines. But that would have taken time, and did I want to take that time if the engine was on fire?

Two months later, another pilot took my crew on the now infamous maximum weight takeoff trip across the pond. The fire light made its appearance and the guest aircraft commander announced it was a known problem and he was going to press on. Although he clearly had superior judgment, my crew set up browbeating him to reversing his decision. After an hour he agreed to come home. They landed after two hours of flight with the engine engulfed in flames. 

As it turned out, there was a loose bleed air duct in the engine that would only work its way loose enough to allow hot air to escape when the engine was at full thrust for prolonged periods, such as during a maximum weight takeoff. It would often take 30 min. to climb to altitude and the fire light usually came on after 20-25 min. The local training flights were never at such a weight and the climb to altitude rarely took more than 15 min. Years later I thought a video camera mounted on the jumpseat would have captured enough to keep troubleshooting the problem. Fast forward 30 years...

Photo credit: James Albright

One of the advantages of flying one particular aircraft exclusively is you get to know it and you more quickly detect when something is amiss. In 2014 I got the feeling the gear extension on our G450 was taking longer than it was supposed to. When in the right seat, I am in the habit of moving the gear handle down and keeping my hand on the handle until it has completed extension and I have three green lights. The green light that indicated the right gear was down and locked was taking almost two seconds more than the left. So, I started verifying that with the synoptic.

Gulfstream said it was all within tolerance and there was nothing to worry about. I said it may very well be in tolerance, but the fact it changed its behavior could mean something was wrong and could get "wronger."

Our airplane has several cameras providing exterior views, one of which is forward of the landing gear, facing aft. While we can view these up front, we don't have a way of recording the video. So I rigged a system in the cabin.

Photo and video credit: James Albright

I simply removed the cushions from the forward divan and secured a camcorder on a tripod using the divan's lap belts. Then we gave it a try.

Keep in mind that the camera is looking aft, so “left is right and right is left.” Based on the video the experts came to the "that ain't right" conclusion and asked us to bring the airplane in. They put the airplane on jacks and verified the problem and isolated the issue to a worn bushing on a timing valve, which is a mechanical piece of wizardry that delays gear extension until the door is clear. They replaced the bushing and the gear’s behavior returned to normal.

The overly dramatic pilot in me thinks that had we not caught this when we did, the bushing might have failed during flight and prevented the gear from extending at all.  My mechanic tells me I am being overly dramatic. Of course, he is right.  Or is he?

Video credits: James Albright

We replayed the tape over and over and found the left engine lagged the right, but when we hit the engage switch the left engine was only slightly behind, 40.2% N1 Left, 45.3% Right.  "That's only 5.1%! Much less than 10!" Wrongo. It comes to [ (45.3 - 40.2) / 40.2 ] x 100 = 13%.

What we had been doing is slowly bringing the throttles to midrange, waiting for them to come up, and then hitting the engage switch. As it turns out, we were attempting to engage at the moment the lag was at its greatest. The aircraft accelerates so quickly that if we waited much longer, we would be beyond 60 kts., where the autothrottles go into "hold" mode. So we had to pull out the books and figure out what has to happen for the autothrottles to engage during takeoff: the throttle levers have to be forward at least 19-deg., the KCAS must be below 60 kts., and the engine N1 split cannot exceed 10%. So we started pushing the throttles forward about halfway and then hit the engage switches without waiting for the engines to spool up. It has worked perfectly ever since.

On this video, look at the top dials in the stack of engine instruments, that's the N1 indication. As soon as the pilot moves the throttles you will see a small circle parked outside the dial race clockwise to show the pilot what thrust setting he has requested. The pilot selects the autothrottles and they engage immediately, because the throttle lever angles were high enough, the airspeed was below 60 kts., and the engines were still near idle but with a split of less than 10%. We were operating our GVII-500 the way we learned to operate our G450. The video helped us to learn our mistake. I notified a GVII users’ group and have since heard from other new G500 pilots who ran into the same problem.

Photo credit: Adobe Stock

Many modern aircraft have system synoptic pages that speak volumes about what is happening "behind the curtain," but how do you know if what you are seeing is normal? It would be a good idea to take a cell phone photo of each synoptic page and leave that on your phone for the day you have to ask yourself, "what does normal look like?" For just a few hundred dollars you can buy a very small video camera and a suction cup mount to record videos of your synoptics from takeoff to landing.

Photo credit: Gulfstream Aerospace

Years ago while flying a Gulfstream G450, one of our regular passengers said he was feeling what he called bumps to the pressurization during cruise flight. I had not noticed but a view of the aircraft's ECS synoptic page showed the pressure jumping up and down a bit. I wrote it all up and set our mechanic loose on the airplane.  He could not find anything wrong.

On our next flight with the same passenger we got the same complaint, so I took a video of the synoptic.

Gulfstream said it was due to changes in the engine settings. (If you look at the video, the bleed pressure does appear to bounce around too.)  We retook the video with the autothrottles disconnected and a clear view of the engine instruments. With the engines and bleed pressure steady, the pressure bumps persisted. We brought the airplane to the service center and after a day of troubleshooting they discovered we had a bad motor on our Thrust Recovery Outflow Valve, a modern version of a simple pressurization outflow valve. They replaced it and the problem went away.

The video helped narrow their focus on the pressurization system and away from the engines and the pneumatic system. That probably saved us a few days of labor on the hunt for a solution.

Photo credit: James Albright

You have to be careful with cameras in any cockpit. You cannot place the camera anywhere it will interfere with controls or pilot egress.  You also have to worry about the camera becoming loose in the cockpit. If you are mounting the camera using a suction cup, make sure to use tie wraps or other straps to ensure that the camera doesn’t fall anywhere it shouldn’t. Finding the right angle to capture synoptics can be tricky too. We have it easier in the GVII, since we don't have a yoke in the way and we can mount a camera to a deployable table that is allowed to be used during takeoff and landing. I bought a surface clamp that I put around a cloth to cinch onto the table. If you are not so lucky, you might try putting a person in the jump seat to steady a camcorder on a tripod.

The newest GoPros have wide angle lenses that can capture a lot from left to right and can record in "4K" resolution and as fast as 60 frames per second.  While you might find what you are looking for by simply playing back the video on your computer, some video editing software can help you zero in on what ails you.

GVII pilot Greg Bongiorno testing his aircraft’s autobrakes. Photo and video credit: James Albright

Many pilots favor a windshield mounted GoPro to provide cool “look at me” videos which, I have to admit, are very cool.  But we use these as tools for improving pilot technique: Is this pilot’s aim point correct?  Is this pilot over-flaring?  How is the pilot’s centerline control?  While you will not find any of our videos on YouTube, we do study them. They have helped us troubleshoot ourselves, as well as our aircraft. The video shows us learning the best speed to override our autobrakes on landing. The process took us three or four landings. Without the videos the process would have taken twice as many flights.

As aircraft become more and more reliant on computers, things can get complicated.  Don't take your mechanic's "that can't happen" as an attack on your observational skills. It could very well be that he was taught that what happened, really can't happen. A video or photo will help you both track down what did happen, and perhaps convince the people who built the airplane that they too have a few things to learn about that cosmic airplane you are flying.