Probable Cause #49: Distraction

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This article originally appeared in IFR Refresher, Feb. 2007.

Probable Cause

Every one of us remembers the old phrase, "Fly the airplane first." The reference is to our first job as pilots, which is to maintain safety of flight and/or operation any time we are sitting in the left seat and the engine is turning. It means that no matter what happens, we continue to fly the airplane and not allow it to come into harm's way. This becomes even more important when distraction and confusion sets in. That's what happened to the pilot of a Cirrus SR20 while flying an instrument approach into the Reid-Hillview Airport (KRHV) near San Jose, Calif. Because of less-than-stellar work by ATC, he allowed himself to become distracted and lost sight of the "big" picture, resulting in a fatal accident. The situation was probably exacerbated by the fact that the pilot didn't have a great deal of flying time and had just gotten his instrument rating. As with most GA accidents, the lack of a cockpit voice recorder makes it almost impossible to deduce with absolute certainty what went on in the cockpit of this SR20. But as you begin to read about the chain of events that led to the crash, it's not too difficult to draw a plausible picture of what the pilot was facing and how the events ultimately unfolded.


Cirrus SR20

The story begins in the late afternoon of Jan. 23, 2003. The private pilot and aircraft owner departed the Napa County Airport (KAPC) at 4 p.m. Pacific Standard Time for KHRV on an IFR flight plan that he had filed earlier. The 57-nm flight, almost directly south, would normally be a picturesque affair, taking one just east of San Francisco Bay. On this day, however, the weather was hardly cooperative, with broken and overcast skies and reduced visibilities in the area. At 4:27 p.m., the Cirrus was approximately abeam the Oakland International Airport and the controller issued an instruction for the pilot to proceed to a navigational fix near the Palo Alto Airport (KPAO). To give you a frame of reference, Palo Alto is located about 16 nm northwest of KRHV. Sandwiched in between the two airports are San Jose International (KSJC) and Moffett Field. The clearance obviously confused the pilot, so he queried the controller about the instruction. After several exchanges, it became apparent that the controller thought the Cirrus was on its way to KPAO, not KRHV. With the misunderstanding resolved, the controller then asked the pilot from which fix he'd like to begin the approach to Reid-Hillview. The pilot responded by requesting vectors to "around OZNUM," the final approach fix (FAF) for the RNAV (GPS) approach to Runway 31R. The controller cleared the pilot to fly direct to OZNUM, a course that would take the pilot on a slight south-southeasterly heading. Instead, the Cirrus turned almost 90 degrees to the west, on a track that would take him directly towards the Palo Alto airport. The controller noticed the turn and asked the pilot if he was proceeding direct to OZNUM, to which the pilot responded that he was "intercepting the course." The controller told the pilot to make a right turn to avoid San Jose traffic and to proceed directly to OZNUM, which he told the pilot was "on the east side of Reid-Hillview." The pilot acknowledged the transmission and made a right turn of approximately 270 degrees, which put him on a nearly southbound course, but still not directly to OZNUM. Only after about three miles on that course did the aircraft turn and tracked direct to the fix. Radar showed the aircraft then flew overhead KRHV nearly on the reciprocal course for the approach, aligned with the fixes OZNUM and ECYON, another GPS fix on the approach.

Button Pushing

Cirrus SR20 Panel

Let's pause the narrative here for a moment. The SR20 was equipped with state-of-the-art avionics, including dual Garmin 430s and an ARNAV ICDS 2000 multi-function display. Although we don't know this for fact, we can reasonably assume that the pilot was navigating by GPS using the Garmin 430s. As capable as the Garmin 430 is, it shares a common flaw with other GPS receivers: It can be difficult to program, especially if you're fairly new to the system and the pressure is on. With that in mind, it becomes easier to imagine what was transpiring in the cockpit at the time. The pilot receives clearance to a fix that's not in his flight plan; perhaps he puts it in the GPS and realizes it takes him away from his route. He now questions the controller, a confusing exchange takes place and he is then given a revised clearance. All the while, he is pushing buttons and twisting knobs on the Garmin, trying to make heads from tails with the information he's presented. It would certainly explain the initial turn to KPAO and the three-mile lag after turning south prior to proceeding to OZNUM. As the aircraft reached OZNUM, there was a change of frequencies. The new controller told investigators that he was aware of issues regarding the pilot's course because he overheard the other controller correct the pilot as he was trying to make his way to OZNUM. The controller said he believed the pilot needed extra attention and he intended to provide it.

KRHV RNAV/GPS Rwy 31R Approach Chart (click here for larger version.

It was at this point that another link was added to this fatal chain of events. The pilot had been cleared to OZNUM, but had not received any further clearance after that. The first controller had cleared the pilot to OZNUM with the expectation that the second controller would provide the pilot with radar vectors to the final approach course. However, by the time the pilot made contact with the new controller, he was already past OZNUM and had turned inexplicably to the east. Instead of giving the pilot a vector, the controller told him to turn towards ECYON. The controller later explained to investigators that the airplane was in a position coincident with a downturn leg and that a turn to ECYON would be the same as a vector to final. While the instruction may have made sense to the controller, it was contradictory to ATC procedure. The Air Traffic Control Handbook (FAA Order 7110.65) states that instrument approaches "shall commence at an initial approach fix or an intermediate approach fix if there is not initial approach fix. Where adequate radar coverage exists, radar facilities may vector aircraft to the final approach course [by assigning] headings that will permit final approach course interception on a track that does not exceed 30 degrees." In this case, ECYON is neither an initial or intermediate approach fix. Plus, the turn towards ECYON would have resulted in an intercept angle of around 40 degrees. The clearance certainly confused the pilot, who had to question the controller about the fix before acknowledging the clearance. The controller then instructed the pilot to descend to 4000 feet. However, instead of making a right turn towards ECYON, the pilot, now flying east of the final approach course over rising terrain, began a turn to the left. The controller, noticing this, asked, "You are going to make a right turn, right?" The pilot answered, "I was making a left turn, but I'll make a right turn now." The controller replied, "Make a right turn. Don't make a left turn." Recorded radar indicated that before the aircraft began the turn that it was on a course toward ZUXOX, the initial approach fix. At that time OZNUM was directly behind the aircraft, and ECYON was in its four o'clock position. It's possible that the pilot had selected the approach from his GPS database and that it was taking him toward the IAF. What's more difficult to explain is why the pilot would turn to the left if he knew where he was in relation to the terrain. And turning to the left would be the long way around to get to ECYON. The turn to the right was shorter. The pilot made the right turn as instructed but briefly flew toward OZNUM. Then he made a slight left turn and joined the leg between ZUXOX and ECYON. Again, it's possible that with the approach selected, the GPS prompted the pilot to join that portion of the approach. When the controller observed the aircraft on that leg, he issued the approach clearance to the pilot. At this point, the controller handed of his duties to his relief, with the instruction that all the new controller had to do was issue the pilot a frequency change for the KRHV tower. An otherwise simple task, this would add another link to the chain, perhaps the fatal one. When the new controller instructed the pilot to change to the RHV tower on frequency 118.6, he had inadvertently given him the frequency for the Palo Alto tower. The pilot asked the controller if that was correct, and the controller insisted it was. The pilot switched over as instructed and spoke to the Palo Alto Tower controller, who told him he was not on the correct frequency. The pilot said he would switch to 119.8 for the KRVH tower. While the pilot was speaking with the Palo Alto tower controller, radar indicates that the aircraft began a turn to the right. At 4:52 p.m. the aircraft was approximately over the JOPAN waypoint, but was now flying almost perpendicular to the course and heading for the high terrain. The pilot reported to the RHV tower that he was "descending from JOPAN, 2000 feet, 5.4 miles from the missed approach point." Note on the approach chart that there is a ridge just east of JOPAN that's above 2000 feet. Within a couple of seconds of the pilot making initial contact with the KRHV controller, the ARTS Minimum Safe Altitude Warning System provided a visual and audible alert at the RHV tower and the Northern California Terminal Approach Control. The controller cleared the pilot to land, then said, "Low altitude alert, check your altitude immediately." The radar indicated that the aircraft was heading toward higher terrain. About 30 seconds later the controller informed the pilot that he appeared to be off course, but the pilot's response was not intelligible. There were no more transmissions from the aircraft.

Point Of Impact

The aircraft collided with power lines and then the surface at the bottom of a ravine in the mountainous area 6.7 miles southeast of the Reid-Hillview Airport. The pilot, the sole occupant of the aircraft, was killed in the crash. The pilot held a private pilot certificate with ratings for single-engine-land and instruments. He also held a valid third-class medical certificate. His logbook indicated that he had 460.7 total flight hours, 362.4 of which were dual received. He had logged 150.3 hours of IFR time, 10.7 of which were in actual conditions. He had 334 hours in the Cirrus and 84.4 hours in the 90 days preceding the accident. He had completed and passed his instrument checkride just 17 days before the accident occurred. The weather at KRHV was reported as ceilings at 1200 feet broken, overcast skies at 8000 feet, visibility of four miles and winds from 280 degrees at 12 kts. The temperature/dew point was 60/59 degrees Fahrenheit and the altimeter was reported as 30.24. The NTSB blamed the accident on the pilot's failure to maintain course for the published approach procedure due to his diverted attention caused by the erroneous frequency assignment provided by ATC. They also attributed the non-standard ATC clearances used to get the pilot established on the final approach course, leading to confusion and likely task overload associated with the repeated reprogramming of the GPS receiver. While most of the pilot's flying time was in the Cirrus SR20, most of it was with a flight instructor present. In fact, having received his instrument rating only 17 days earlier, this may have been his first solo flight in actual instrument conditions. The accident report did not comment on that aspect. Investigators interviewed the designated examiner who issued the pilot his instrument rating. He said that the pilot was detail oriented and was very knowledgeable about the aircraft he was flying. But did the pilot understand how to fully utilize this equipment? Maybe he never had the opportunity during his training to reprogram a flight plan in mid-flight, or if he did, it was with the help of an instructor. It would appear that his workload was high as he tried to fly the aircraft and program the Garmins and that may have led to a lack of positional awareness throughout most of the flight. There is no doubt that there was confusion in the cockpit of the Cirrus that afternoon. How much of the confusion was caused by the controller's mistaken frequency change, we'll never know. The NTSB determined another factor in this accident was the failure of ATC to provide the pilot with a timely and effective safety alert concerning his deviation from the proper course. It was influenced in part by the features of the radar display at both facilities, which made the deviation more difficult to detect, and the nature of radar as a secondary tool for a VFR tower controller. How can you avoid the situation in which this pilot found himself? First, do not depend on equipment that you don't know how to use properly during IFR flight. Make certain that you are familiar with every piece of avionics gear that is installed in the airplane you fly. And don't fly an airplane that you have not flown before under IMC conditions until you know how to use the gear. All the new avionics gear is great to fly with, but there is a learning curve with each installation. Any time a controller's instruction or intention is not clear ask him or her to clarify it. And be aware of your position relative to the final approach course, the airport and rising terrain. When in doubt, tell the controller you'd like to start from scratch, by either getting vectors for the final approach course or a clearance to an initial approach fix for a full approach. Trying to figure out where you are in the middle of an approach is a sure recipe for disaster. Remember to fly the airplane first at all times. Keep it under control and on course while handling other issues or problems after that. If you don't do that, you are essentially giving up control of the airplane to Mr. Murphy, who is no friend to safe flight.
More accident analyses are available in AVweb's Probable Cause Index. And for monthly articles about IFR flying including accident reports like this one, subscribe to AVweb's sister publication, IFR Refresher.