Lower Won’t Work

Certain rules allow us to descend below minimums, but only by so much. And pushing it too far means huge increases in risk, often with tragic results.


There’s always that difference between a textbook procedure, such as an approach to published minimums, and real-life conditions that are rarely so clear cut.

While we usually train by flying right to minimums and then frequently flying the missed, how often in our actual flying do we miss and do it again, or divert to an alternate? How often do we get caught by surprise when the ceiling we’re expecting to break out of is lower than we thought (or lower than we need)? For those of us operating under 14 CFR Part 91, how often do we consider or actually find ourselves pushing the looser legal limits of landing under IFR?

In the end, it’s all up to the PIC to decide where, when and how to fly a procedure, but any pilot who deviates from published minimums or what should be standards of flight planning and decision making is pushing the limits of what can actually work, even flying the simplest of procedures.

Let’s examine a tragic illustration of that reality.

Bonanza In LIFR

On the evening of June 24, 2011, a Beechcraft A36 Bonanza with three people and two dogs on board crashed near the Charlevoix, MI airport during an approach in what was reported to be low IMC. The pilot, passenger and one dog were killed; one passenger was seriously injured and the second dog was unhurt.

About 45 minutes before the crash, the PIC, who had departed about 5:30 p.m. from Fort Wayne, Indiana for Boyne City Municipal (N98), told ATC he needed to divert to Boyne Mountain Airport (KBFA) just a few miles southeast because his intended destination lacked instrument approaches, according to the report. (Presumably, today’s two RNAV approaches didn’t exist then.)

The pilot requested the RNAV 35 approach to Boyne Mountain (KBFA) and ATC cleared him to ELBOT, the straight-in initial fix about 13 NM south of the field. A half-hour later, at 7:17 p.m., the Bonanza missed the approach and Minneapolis Center received the pilot’s request to divert again. This time his requested destination was for Charlevoix’s (KCVX) RNAV 27.

ATC cleared the aircraft to COKOS, the straight-in IAF located 13.6 NM from the runway. Three minutes later, the pilot was cleared for the approach. Shortly after that, the pilot received and acknowledged changing to the Charlevoix’s advisory frequency. People who were at KCVX at the time told investigators afterward they heard the Beech pilot call in on the approach.

Meanwhile, the ceiling was 200 feet with one mile visibility, according to witnesses who saw the airplane flying out of the clouds “approximately halfway down Runway 27.” The Beech powered up, turned left, then right (circling a water tower southwest of the runway), all at about 200 feet AGL. The pilot then apparently attempted a right circling approach to Runway 27, but stalled in a nose-high left roll and crashed.

The Weather

Archived meteorological data for the northwestern corner of Lower Michigan indicates that the weather had deteriorated from marginal VMC to low IMC from the time the Bonanza departed Indiana and diverted in Michigan. By 7 p.m. local time, the automated station at Charlevoix was reporting a west wind, ceiling overcast at 200 feet, and visibility two miles in rain. The straight-in MDA is 438 feet above the touchdown zone. Circling adds another 180 feet.

At 7:14 Charlevoix reported visibility 1-3/4 miles, mist, sky broken at 400 feet. Neither Boyne City nor Boyne Mountain has weather reporting. At 7 p.m., when the Beech was inbound to Boyne Mountain, the weather at nearby Gaylord Regional Airport was 280 degrees at 10 gusting 17, 10 miles visibility, and an overcast ceiling at 900 feet. Boyne Mountain’s straight-in MDA is 1121 feet above the touchdown zone.

We must first question the pilot’s decision to file to N98 with no instrument approaches when the weather looked like it would be MVFR at best. It’s legal to file IFR to an airport with no approaches, if an alternate is filed (91.169).

Plus, that alternate must comply with 91.169 (c)(1)(i)(B) and have at least 800-2 for non-precision approaches. Perhaps the pilot expected he could get down to VMC at N98. Or, he gambled, knowing that KBFA was close and offered an appropriate alternate with its RNAV approach. We don’t know from the report what alternates were filed, if any.

The KBFA Approach

In any case, Boyne Mountain became the new destination. Its RNAV 35 is a typical procedure. From ELBOT, it’s 2500 feet to the FAF, ROCOR, with an 11-degree course change at ROCOR. Assuming the Bonanza flew at or above 91 knots, the Category B LNAV straight-in MDA is 1840 feet with visibility 1-1/2 miles. That would require breaking out of a nearly 1200-foot ceiling.

It’s likely that the clouds at KBFA were considerably lower; the report at Gaylord at 7 p.m. local showed a 900-foot overcast with 10 miles visibility, plus a 2-degree temperature-dewpoint spread (13/11) that could have made flight visibility worse.

The Bonanza missed the approach at Boyne Mountain, but the NTSB doesn’t report the pilot’s flight conditions at that time. So we know neither the weather that the pilot was experiencing nor his mindset when he missed. What was the actual ceiling? Did he ever see the runway? It’s also not clear exactly when he began the missed, which is cut-and-dry: Fly the runway heading to 3000 feet and fly direct to CEDOS for the hold.

Since the pilot diverted to Charlevoix instead of trying the Boyne Mountain approach again, we might assume he didn’t think another attempt would produce any better results.

The KCVX Approach

Charlevoix was the Bonanza’s third destination. The RNAV 27 began crossing COKOS at or above 3000 feet, with a descent to 2600 feet after COKOS. Inside HISUM, there’s a stepdown at HOMVO to 1300 feet, with a straight-in MDA of 1100 feet (438 feet AGL) and one-mile visibility. The circling MDA is 1280 feet. There’s a VDP 1.3 NM from Runway 27, but it’s assumed that visual contact with the runway environment—to allow a descent below MDA—didn’t come into play on this approach given the lower ceiling.

In fact, witnesses reported 200-1 when they spotted the Beech. The missed includes a climbing left turn. The pilot did turn left, but then turned right—possibly to avoid the water tower, turn back, or both. The NTSB’s probable cause notes “the pilot’s decision to not execute a missed approach in weather conditions below minimums.”

More On The Regs

Even if the pilot was proficient in low IMC, the weather worked against him at all three airports. He filed to a VFR-only airport, then diverted to a field with relatively high minimums that could be reasoned to be below minimums, before diverting to Charlevoix, which offered lower minimums but with weather still too low to complete the approach.

While the visibility requirements of 91.175(c)(2) were assumed to be met, the missed-approach requirements were not. The reg says the pilot “shall immediately execute an appropriate missed approach…whenever an identifiable part of the airport is not distinctly visible to the pilot during a circling maneuver at or above MDA unless the inability to see an identifiable part of the airport results only from a normal bank of the aircraft during the circling approach.” (Emphasis added.)

It happens: Weather deteriorates and the pressure to land grows after multiple attempts. This can lead a pilot to do things he might not normally do, and certainly wasn’t trained to do, such as continue a procedure well below published minimums. In this case, both the rules and the pilot’s abilities were pushed beyond their limits.

Elaine Kauh is a CFII in eastern Wisconsin. She is well acquainted with summertime IMC and fast-changing ceilings around the Great Lakes.


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