Probable Cause: Marginal VFR and Complacency of the Familiar
An IFR pilot may choose to fly VFR on a nice day -- but how good does
''nice'' have to be to let go of the IFR safety net? This week's Probable Cause
report investigates the issue.
IFR accidents typically fall
into a few specific categories: Someone will get it wrong on climbout or
approach, weather smites an unsuspecting pilot or a plane encounters something
substantially more solid than a puffy cloud.
Which makes the
following accident interesting in what the pilot didn't do. It also highlights
the traps into which IFR pilots can fall, especially when conditions appear
benign and the idea of filing and flying IFR may seem unnecessary.
For me, this particular
accident also hits a little closer to home because it took place at a former
employer of mine. The incident happened a few months before I was hired there,
so I never got to know the pilot. But all accounts from those who did know him
indicate he was a good, safe and conscientious pilot.
If you read the
NTSB accident report, the cold hard facts in this incident appear simple. The
29-year-old pilot, flying a Piper PA-32R Lance, was en route from Greenville
(KPGV), in eastern North Carolina, to Concord, N.C., (KJQF) about 20 miles
northeast of Charlotte. The pilot was employed by a Part 135 cargo carrier and
was transporting bank checks for one of its customers. It was mid-March and sky
conditions were clear at the time. Capitalizing on this, the pilot elected to
conduct the flight under VFR conditions and, armed with an onboard IFR-approved
GPS, set off for KJQF. At around 4:30 p.m. and about halfway to its
destination, the plane struck a guy wire supporting a 1,749-foot-tall
television tower.
According to the
accident report, a witness saw the Piper flying lower than he had seen other
planes fly over the tower on previous occasions. As it collided with the wire,
the plane "jolted to the left and exploded in mid-air," the report
quotes the witness as saying. The NTSB determined that the plane struck the
tower at around the 1,425-foot level, or around 1,825 feet MSL. The pilot was
killed and the impact toppled a section of the tower. Although the plane was
destroyed by the impact, company records show it was properly maintained and
the NTSB ruled out mechanical problems as contributing to the crash.
In the end, the
NTSB determined that the probable causes for the accident were the pilot's
inadequate visual lookout and his failure to maintain obstacle clearance.
While it would be
hard to argue the report's conclusions, they raise a deeper question: Why did
an experienced IFR pilot decide to go VFR at low altitude and find himself on a
collision course with one of the few tall obstacles along his route?
Possible
Scenarios
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As
is sadly the case with fatal accidents, we will never know the true answer to
that question. We can only surmise -- guided by experience with this type of
flying -- about what went into the pilot's decision-making process that day.
The goal here isn't to find fault, but to explore the potential false traps
that were in place so we can learn from this unfortunate event.
There is little
doubt the pilot was experienced. According to company records, he had been with
the company for almost nine months and had a little more than 1,700 total hours
with around 600 hours in Piper Lances. In addition to being instrument current,
he had commercial and flight-instructor certificates and was a company check
airman. He also held a ground instructor certificate with advanced and
instrument ratings. A toxicology test taken after the accident showed no traces
of drugs or alcohol.
The routing from
KPGV to KJQF takes you essentially on a westerly heading. A direct-line plot
shows the track passing one mile north of the tower as it was depicted on the
Charlotte Sectional. If you are to file an IFR flight plan for this route, even
direct, your clearance would read direct to Raleigh (RDU), then Liberty (LIB)
followed by the NASCAR 1 arrival. By taking you over the top of KRDU, ATC keeps
you out of the northeast/southwest arrival and departure corridors that serve
the airport, while the NASCAR arrival organizes the flow of general aviation
traffic into the busy Charlotte terminal area. You could request a direct
routing, but during the late afternoon push -- which was when this accident
happened -- it is rarely granted. The pilot most surely knew this.
Compared to the
direct routing, the IFR routing takes you slightly further north. Glancing at a
chart, the detour might seem significant, but in actuality it only adds six
miles to the total direct distance of 163 NM.
There's an aviation
axiom that states that we can never get there fast enough. This attitude is
fostered especially in the freightdog community, where "fly fast" is
akin to gospel. This could explain why the pilot elected to forgo the IFR flight
plan and launch direct VFR instead. But why was he so low?
The NTSB report we
obtained did not include any winds aloft information for that day. But writing
from experience, prevailing winds in North Carolina are typically from the
west, especially if you have a strong high-pressure area sitting over the
South. It's not unusual on a westbound trip to have a 30-knot headwind on the
nose. Perhaps that was the case that day and the pilot decided to stay low,
where the winds usually aren't as strong.
How
Clear Is Clear?
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The
weather at the time was clear, or more accurately, clear of clouds. While we
often equate that with visual conditions, that is not always true. The accident
report included a surface weather observation report from a nearby airport
taken half an hour after the accident, showing a visibility of 10 SM.
Incidentally, the winds were from 160 degrees and 6 knots, showing that the
winds, at least near the ground, were light.
Unfortunately,
automated weather detection equipment isn't foolproof and it can report
conditions that aren't indicative of what is going on in the area. By coincidence,
I was flight instructing at the time the accident occurred in an area not more
than 50 miles away. I cut the lesson short because haze had severely reduced
flight visibility, especially when facing into the sun. I had even told my
student, who was only a few lessons into his flying career, that for all
practical purposes we were IFR. The comment stuck in my mind later that evening
when I heard about the accident on the local news.
The direct course
from KPGV to KJQF is about 265 degrees. The NTSB estimated that at the time of
the accident, the sun was 22 degrees above the horizon with a true bearing of
250 degrees. In other words, the pilot was flying with the sun right in his
eyes. The Piper Lance, like most piston singles, has a Plexiglas windshield,
which is prone to hazing and crazing. These effects are magnified when facing
the sun head on. Add to that the natural haze that existed and forward
visibility is almost non-existent. By the time the pilot saw the tower and the
guy wires -- if he ever saw them -- it was probably too late.
Weighing
The Options
Risk assessment is
a skill we exercise every moment we fly. The only way we won't get killed in an
aircraft accident is to stay on the ground and live in a cave. That's obviously
impractical, so we weigh the risks we are willing to take versus the gains to
be made. Sometimes the answer is very clear. Got a line of Level 5
thunderstorms heading your way? Let's wait it out. Better yet, let's drive.
Sometimes, however, the answers are a little muddier.
Based on an average
groundspeed of 110 knots (which is factoring in a 30-knot headwind), it would
have taken one hour and 29 minutes to fly the direct route versus one hour and
32 minutes for the IFR route. In this case, a three-minute shortcut shouldn't
warrant giving up the protective umbrella that an IFR flight plan provides.
However, staying low where winds are lighter, giving a ground speed of 125
knots, the direct route would have taken one hour and 18 minutes, a savings of
14 minutes. With a ground speed of 135 knots, the time shortens by another six
minutes.
Perhaps the pilot
wanted to please his customers -- and his boss -- by getting to KJQF early. Or
maybe the reasons were more self-serving. Regardless, he must have weighed the
options and decided the benefits outweighed the risk, which in his mind were
probably minimal. Not only was the weather clear, although the visibility was
marginal, but the pilot had flown this particular leg on numerous occasions
before and he was familiar with the area.
It's this
familiarity that may ultimately provide the final piece of the puzzle. The
plane was equipped with an IFR-approved GPS and there's no doubt he would have
used it to navigate his direct course. While the GPS is a great tool, it also
introduces a level of complacency into the cockpit. With its steadfast
accuracy, pilots -- especially those who regularly fly IFR -- have developed a
habit of keeping their eyes inside the cockpit.
Lessons
Learned
It's unfair to
second-guess someone's decision after the fact. In hindsight it's easy to say
that the pilot should have filed IFR and conducted the flight under the
watchful eyes of ATC. But faced with a 20-minute time savings, I'm sure many of
us would be tempted to do what this pilot did.
So what can we do
as IFR pilots to avoid such an unfortunate incident?
Begin by make a
realistic assessment of the gains to be made by flying VFR versus the safety
that comes with filing IFR. This gain/risk threshold will vary from pilot to
pilot, and is going to be influenced by numerous factors. Some of those include
the pilot's comfort level with VFR flying, the anticipated weather en route and
the type of mission that is at hand.
Note that I didn't
mention familiarity with the local area. This is one of the traps. In this
particular case, the pilot lived 10 miles from the tower with which he
collided. If he was over unfamiliar territory, he may have been more vigilant
or stuck with the IFR flight plan and let ATC keep him clear of traffic and
obstacles. Should you go the VFR route, make sure you're armed with all
appropriate information. Low altitude IFR charts do not depict obstacles and
are therefore misleading. It's always a good idea to carry a Sectional or WAC
chart with you at all times, even if you regularly file IFR.
Then consider the
weather and the geography. Clear in Arizona is not the same as clear in North
Carolina. Inversion layers will trap humid air with the resulting haze greatly
limiting forward visibility. If you're in a part of the world you're not
familiar with, talk to a local pilot or get some insight from the FSS briefer
when you're filing your flight plan.
Only then should
you ask if the time saved is really worth it. In the case of this unfortunate
young pilot, his savings were never realized.