Archive for 2014

A jet goes down

Wednesday, December 10th, 2014

KGAI Accident map 2This week a Phenom 100 business jet crashed about a mile from the Gaithersburg, Maryland, Montgomery County Airpark (KGAI) runway.

The jet plunged into a house with a young mother and two children inside who perished along with the pilot and two passengers. Annually, there are very few off-airport ground fatalities, which make these accidents dramatic and newsworthy. No matter how clinically we dissect the accident report, the human loss is tremendous. Dozens of lives, if not hundreds, have been painfully impacted—some disastrously. Our sincere condolences go out to all the families, friends, and co-workers.

The Phenom was on an IFR final approach although the weather was VMC. Scattered clouds were reported around 2,100 feet with 10 miles visibility and light winds: Easy day—right up until something happened. In such circumstances we try to make sense and understand for several reasons. We don’t know the details yet, but it’s looking like a rather basic failure of airmanship—our old nemesis—the stall. The aircraft was equipped with a flight data recorder (FDR), which the NTSB recovered and the answers will be forthcoming. These comments are speculative until the final report is released, but early information released by the NTSB points to a stall—no mechanical failures.

Getting well below ref speed invariably leads to bad things: The FDR preliminary data showed that about 20 seconds prior to the crash the stall warning annunciator and voice alert was triggered. There is also a stick pusher but it’s unknown at this point whether it activated. Vref speed for the Phenom was somewhere around 105 knots—the speed at which it should have been approaching with gear and flaps down. The FDR showed a speed of about 88 knots and witnesses saw the wings rocking followed by a reported pitch down.

So why does a pilot with approximately 4,500 hours and most likely considerable training in the aircraft and simulator wind up in this circumstance? Hard to answer. There is irony here because in March of 2010, the pilot had an accident at KGAI in his previous aircraft, a TBM 700. In that mishap the pilot lost directional control and initiated a go-around—the TBM stalled and crashed with no injuries.

Was the jet following another slower aircraft? Don’t know for sure about that yet but indulge me for a moment. (The following comments do not necessarily apply to this accident.) There is a natural tendency to slow the rate of closure on the lead aircraft in hopes that a second trip around the pattern might be avoided. It’s not unusual for larger, faster aircraft to make straight-in approaches. Things get complicated when smaller VFR aircraft are flying their normal patterns. While one might technically have the right-of-way in the slower aircraft, I’ve always felt it both prudent and courteous to let faster airplanes play through.

Some will bristle at the high and mighty getting priority but consider this: Stabilized approaches are all-important in any airplane. Because of inertia and maneuverability bigger airplanes need more room to get stabilized. It doesn’t take much for a C-172, Cherokee, or even a high performance single piston to establish itself. Twins, jets, and turboprops need time, space, and airspeed to get settled.

Tower and approach controllers will almost always vector or have a slower aircraft extend downwind to avoid the impossible aerodynamics that may have occurred here. Fast movers generally, but not always, appreciate it and should say, “Thank you,” when someone yields. At a non-towered airport like KGAI, straight-in approaches are not an entitlement in VMC, and pilots should be prepared for the go-around. CFIs, teach your students well to understand that the worst place to be is in front of a much faster aircraft on final. They’re distracted, you’re distracted, and they may not see you. You could be dead right and that’s small consolation. (Same thought process works well on the highways.)

When following another aircraft on final, set a minimum speed that is safely above the stall. Don’t let ATC instructions, snow, rain, or dark of night deter you from the lifesaving go-around when the deadly stall starts to steal your lift.

Local media has presented a balanced view up to this point, although interviews with neighbors concerned about flight operations are beginning to surface. The airport was built in 1959, and like so many it was encroached upon as incompatible land planning and usage lead to building residential areas in flight safety zones. This is not to sanction carelessness or complacency in any way on the part of pilots, but zoning boards should understand that they have responsibilities as well.

Stay tuned, fly professionally, and know that life is fragile in so many facets. We will be watching developments closely.

If it’s been awhile since you brushed up on practical aerodynamics, spend a few minutes with the Air Safety Institute’s “Essential Aerodynamics: Stall, Spins, and Safety” online course.

Helping pilots improve their skills and enhancing GA safety is a core tenet of the AOPA Foundation’s Air Safety Institute and its educational programs. Your contribution funds these activities and ensures ASI continues to address the needs of pilots everywhere. Visit the AOPA Foundation’s online auction to bid on an item or make a donation today.


Thursday, December 4th, 2014

g1000-svt-MGLast time we talked about a VFR training flight that tangled with mountainous terrain in the dark, and there was some discussion regarding synthetic vision or syn-vis. I had recommended the old-fashioned way of looking at the chart, VFR or IFR, to determine the Maximum Elevation Figure (MEF) or the Minimum Obstruction Clearance Altitude (MOCA) and Off Route Obstruction Clearance Altitude (OROCA).

A few of you wrote to suggest how helpful it was having the world electronically presented. We agree. A few old-timers will remember TWA 514, a Boeing 727 that slammed into a ridge just west of Washington, D.C.’s, Dulles Airport on a stormy VOR approach. The crew debated what “cleared for the approach” meant and what was a safe altitude for descent. That changed the whole system and lead to the formation of NASA’s Aviation Reporting System (ASRS). That landmark accident is required reading for anyone not familiar.

In the aftermath, all airliners were mandated to be equipped with ground proximity warning systems or GPWS. It sort of worked but didn’t look sufficiently forward. Airplanes continued to have terrain encounters and an improved system called enhanced GPWS was mandated. This has worked really well but not quite perfectly. (Airline readers may wish to weigh in on this.) With GPS, flat screen displays, and terrain mapping, GA moved into a new era about 15 years ago. If you’ve got the good stuff on board there really is no excuse to hit the ground or an obstacle. But it’s moderately to extremely expensive and updates are recommended.

A short hangar story: On a recent daytime VFR flight into the D.C. Special Flight Rules Area (SFRA) I was cleared into that sacrosanct airspace and told to remain clear of Class Bravo airspace. The floor of that airspace is 1,500 feet, and the small, but immovable ridges were coming up below me.

It was windy and bouncy down low. I asked ATC if they might grant another 500 feet as the last generation terrain map (not syn-vis) on my GPS unit was showing lots of yellow and a “terrain advisory.” That means less than 1,000 to go to touchdown. The box was insistent, as it should be. The terrain database was original to the unit—circa 2007. To be sure, while we’ve had an earthquake in the D.C. area (not political) the hills just haven’t moved all that much since then.

The tower topography, however, has changed and is changing drastically, and so tiptoeing through the tulips is not recommended even with a current database. A data point for your consideration: It’s too soon to know about any ground proximity systems aboard a VFR Piper Lance that collided with a wind turbine a few hundred feet agl at night in MVMC to IMC conditions, resulting in four fatalities. (South Dakota in April 2014.)

On my return flight out of the SFRA, it was well after dark but great VFR weather. Slide out at low altitude VFR and remain clear of Bravo, refuse that clearance and work out a VFR clearance into Bravo, or file IFR? What would you have done?

Syn-vis is excellent and my uneducated guess is that we will see fewer controlled flight into terrain (CFIT) accidents going forward, especially if the FAA relaxes the requirements for lower cost panel-mounted gear. It should be considered supplemental and installed with fewer restrictions than what currently exist. Pilots also need to understand that the good is not perfect so a terrain avoidance plan is still an excellent idea.

Belt and suspenders may not be stylish, but I guarantee your posterior will not be exposed. Would like to hear from you—both good and not-so-good experiences—regarding syn-vis and other electro-vision devices.

Helping pilots improve their skills and enhancing GA safety is a core tenet of the AOPA Foundation’s Air Safety Institute and its educational programs. Your contribution funds these activities and ensures ASI continues to address the needs of pilots everywhere. Visit the AOPA Foundation’s online auction to bid on an item or make a donation today.

Mountains 1—Aircraft 0 (Again)

Thursday, November 20th, 2014

KHSP google mapsDespite the flippant headline, there is always tragedy with controlled flight into terrain or CFIT accidents. It remains a steady fatality producer with highly lethal results. The accident in question occurred last week in southwestern Virginia and is in the preliminary stage of investigation. My usual caveats and disclaimers apply concerning conclusions.

The night VFR training flight had a student and an experienced CFI on board. Good VFR conditions prevailed, but over the mountains one is often on the gauges with few ground lights to guide the way. The Cessna 172S had departed Frederick, Maryland, on a routine training mission to Winchester, Virginia (KOKV), which is on the edge of higher terrain.

For reasons yet unknown, the decision was made to go on to Hot Springs, Virginia (KHSP), which is definitely in the mountains. There was no contact with ATC, and according to radar the Cessna impacted the mountain at about 3,100 feet, roughly 300 feet below the ridge line at a steady ground speed of 87 knots. It’s too soon to tell if there were any mechanical malfunctions. The student survived but the instructor did not. We don’t often get an insight into the thought process of CFIT pilots so this accident may provide some learning possibilities.

When flying at night, which is a great time for IFR training, we recommend IFR procedures. This works well for VFR pilots too. The magic of IFR, or just using those procedures to keep aircraft from whacking the ground, is in the numbers. Specifically it’s the numbers on the chart—whether it’s paper or electronic. The altimeter is your friend and the ultimate arbiter between an uneventful landing and a tragedy.

The Air Safety Institute produced the Terrain Avoidance Plan (TAP), which suggests just a quick look at a sectional or low altitude en route chart to determine what the minimum altitude should be until it’s time to come down. The VFR Maximum Elevation Figure (MEF) on sectionals provides no separation, unlike the Minimum Obstruction Clearance Altitude (MOCA) and Off Route Obstruction Clearance Altitude (OROCA) minimums on IFR charts. Add at least 1,000 feet to the MEFs. The quadrant MEFs bordering the accident site were 5,100, 3,600, 4,800, and 4,000. A VFR westbound altitude of 6,500 feet would be just the ticket!

KHSP’s field elevation is nearly 3,800 feet msl and is surrounded by mountains. The instrument approach procedures chart shows a minimum safe altitude—except when on a published route—of 6,000 feet. How could it happen that the CFI chose only 3,000? We don’t know.

When flying in unfamiliar areas pay a lot of attention to the vertical. Horizontal is important too, but altitude is everything. Superb navigational accuracy with GPS and moving maps can generate considerable confidence. Direct to anywhere is easy in the dark, but we still don’t see well. Even in good VFR, a hillside with only a few lights disappears into the darkness.

On-board terrain databases will help as they light up the obstacles that humans can’t see, but they are intended as a supplement, not primary, to see and avoid the planet. Years ago, an early Cirrus model attempted a night scud run up the Columbia River gorge apparently seduced by glowing electrons in the panel despite warnings that it was illegal and illogical to do. The aircraft hit the same rock outcropping as too many of his less-equipped predecessors did.

Without belaboring the point, which I already have, if pilots don’t have a terrain avoidance plan my bet is on the mountain. How about you?