All posts tagged 'Aircraft Accidents'

The Importance of Checklists: 4 Accidents That Checklist Use Could Have Prevented


Photo 1981 by J-E Nystrom, Helsinki, Finland/CC 3.0

It’s human nature to be complacent. We’re all lazy, right? But aviation isn’t an industry that welcomes complacency, and even the slightest oversight on behalf of a pilot in command can mean the difference between a successful flight and an unsuccessful one.

My flight students get tired of me reminding them about checklists. Before we even get into the airplane, I can often be heard saying: "That preflight checklist is there for a reason." And on downwind, every single time: "Before Landing Checklist." Some people understand the tedious nature of checklists and accept it; others defy it.

Why don’t pilots use checklists? Probably because they don’t expect anything bad to happen when they don’t. After all, they’ve skipped a checklist- er, many checklists - before and nothing bad happened. Maybe they remember all of the items, after all. Or maybe it’s true that 999 out of 1,000 times, a forgotten checklist item still results in a successful flight, which reinforces the pilot’s belief that it isn’t complacency, but skill, that gets him back on the ground safely. Unfortunately, this couldn’t be more wrong.

We’d all like to think that we’d never end up crashing because of a forgotten checklist item. But here are a few examples of average pilots who failed to accomplish checklist items or otherwise got into trouble for a checklist-related item. We’re not any different. We’re not immune. At the very least, it’s embarrassing to end up like one of these pilots; at the worst, fatal. If using a checklist can potentially prevent you from embarrassment or death, shouldn’t we just use it?

Here are four accidents where proper checklist use would probably have prevented the accident entirely:
Gear Down and Locked
As seen on YouTube, the pilot of this Piper Aerostar twin-engine airplane landed without gear at Aero Acres Air Park in Port St. Lucie, Florida. And then, to everyone’s surprise, he took off again. You can see from this video that the airplane is coming in too fast and unstable, and the pilot decides to go around only after touching down. Unfortunately, the pilot not only forgot the gear, but he forgot his go-around procedures. The pilot claims that he intended to go around, retracted the gear and all of the flaps prematurely and sank to the runway. Once airborne, the pilot is said to have flown the aircraft all the way back to his home in Ft. Lauderdale- about 100 miles.

This is only one report of many, many gear-up landing situations. Pilots: Don’t forget your GUMPS checklist!

Flight Controls Free & Correct

Earlier this month, the NTSB released an animation highlighting the crash of a Gulfstream IV in Bedford, Massachusetts last year. The aircraft skidded off the runway after a failed rejected takeoff, killing seven people on board - two pilots, a flight attendant and four passengers. The reason for the crash? Failure to check that the flight controls were free and correct before takeoff, and subsequently failing to expedite a rejected takeoff once they determined the problem.

The NTSB report states: "A review of the flight crew’s previous 175 flights revealed that the pilots had performed complete preflight control checks on only two of them. The flight crew’s habitual noncompliance with checklists was a contributing factor to the accident." Sadly, seven lives were lost because basic checklist procedures were not followed.

Water Contamination
There are several ASRS reports from pilots who have lived through off-airport landings due to engine failure. Many of these emergency situations are due to engine failure from fuel starvation. In many of those cases, water contamination was the culprit. In this ASRS report, a man describes his lackadaisical preflight habits after his Grumman Tiger engine quits due to water in the fuel tanks:

"Although I did not discover the water prior to takeoff, I have learned a valuable lesson. I feel that I had gotten complacent in my approach to the pre-flight in that I never found condensed water in my tanks before due to keeping them full at all times." He admits to failing to sump the fuel carefully to check for water.

Got ATIS?
In the early days of flight training, it might not be apparently obvious why a student’s flight instructor emphasizes the importance of getting a current altimeter setting. If the flight is conducted in VFR, the altimeter can be off by 100 feet and it might not matter much. It’s not until a pilot flies an approach to minimums that he realizes the value of setting the altimeter correctly. Being 100 feet lower than you intend when you’re descending on an approach can mean crashing into the runway or just short of it.

Knowing how an altimeter works and accounting for altimeter error will only keep you out of trouble if you set it correctly. We’ve all heard stories of pilots being to low or too high during an approach into IMC. This compilation of NASA ASRS reports tells how altimeter errors can lead to altitude deviations, traffic separation violations and landing accidents.

The NASA report states, for example, that, "A helicopter accident resulting in four fatalities was attributed at least in part to an incorrectly set altimeter during a period of known low barometric pressure. The report from the Canadian Aviation Safety Board states: ‘The helicopter was being used to transport personnel to work sites across a large frozen lake. An approaching low pressure area with snow and high winds...reduced visibility to near zero in some areas. The pilot most certainly encountered adverse conditions and altered course to circumvent the worst areas. The aircraft was later found...wreckage was widely scattered. The altimeter showed a setting on impact of 30.05; the correct setting would be about 29.22, causing the altimeter to read about 800-850 feet high. The altimeter had obviously been set two days previously [apparently during a time of high barometric pressure-Ed.].’"

Incorrect altimeter settings can be fatal. Checklist procedures should always include getting the current altimeter setting occasionally during flight and always before landing.

Unforecast Icing Conditions: How Would You React?

Unforecast Icing Conditions
Photo © UCAR

Winter usually means great flying weather, but the cold weather also brings its own set of challenges: Snowy runways, cold preflights and dangerous icing conditions. For general aviation pilots, one of the biggest risks of flying in cold weather is the possibility of structural icing.

According to AOPA, aircraft structural icing was the cause of more than 150 accidents over a recent period of 10 years. Icing can be present, even when it's not forecasted. As pilots, it's important to know about weather patterns and what to do should icing begin to develop on your aircraft in flight.

I read an accident case study recently that I think serves as a good reminder to stay alert for icing conditions, even if icing is not in the forecast. You can view the details of this particular accident case study, in which a pilot of a Cirrus SR22 en route from Reno/Tahoe International Airport (RNO) to Oakland, California encountered inadvertent structural icing conditions and crashed into mountainous terrain, here.

By all accounts, the pilot performed his preflight preparation responsibilities normally. According to AOPA's accident analysis, he spent time reviewing the weather, including a full weather briefing, which stated that there were no AIRMETs or SIGMETs or precipitation in the area. The Cirrus SR22 was even quipped with an icing protection system, although it was not approved for flight into known icing. So what went wrong?

The NTSB's probable cause report states that the cause of accident was the pilot's loss of control due to an inadvertent icing encounter. Interestingly, the report also cited an inaccurate weather report from the NWS Aviation Weather Center as a contributing factor.

While there was a low probability for icing conditions according to the NWS, there were a few red flags that may have changed the outcome for this Cirrus pilot if he took notice and reacted. For example, the weather briefer indicated a low freezing level of 6,000 feet and approaching precipitation, although it was dry at the time. Additionally, as the Cirrus departed, an incoming Southwest Airlines 737 reported unforecasted moderate rime icing at 17,000 feet. The weather report also stated cloud tops were between 17,000 and 20,000 feet - well above the service ceiling of the Cirrus. This should have alerted the pilot that climbing above the clouds wasn't an option.

This accident is testimony that as pilots, the more we know about weather and icing conditions, the safer we'll be. While forecasts are helpful, the lack of forecasted icing conditions doesn't always mean that we're in the clear. Below are a few reminders and tips for winter flying.

  • Know your aircraft systems: There's a difference between de-icing and anti-ice equipment, and there's a reason that many aircraft with anti-ice systems are still not approved for flight into known icing conditions. Research and learn about your aircraft's specific systems and how it will react in icing conditions.

  • Know your weather: There are a few items to pay close attention to in the weather briefing, such as cloud tops, freezing levels, and of course AIRMETs, SIGMETs and PIREPs. But a good review of weather theory is helpful in determining the effects of incoming weather systems and fronts, as well as certain areas like over mountains or near water, where icing is common.

  • Know when and where icing occurs: Icing usually forms when the aircraft surface (NOT the outside air temperature) is below freezing AND where there is visible moisture. Icing can also occur inside of a "wet" cloud - a cloud with super-cooled liquid water droplets in it.

  • Know what to do when you encounter icing: You have three options if you encounter icing in your aircraft: Climb, descend or turn around. Which one of these you choose will depend on the cloud height, temperatures and your location and terrain. (FYI: Contrary to what many people are told, climbing is not always the best option, as the case study above demonstrates!) If there's even a small chance that you'll encounter icing conditions on your flight, it's best to fully prepare beforehand with multiple exit strategies. Know the cloud tops, the temperatures and the locations of alternate airports. And always communicate to ATC immediately if you find yourself in an icing situation. The pilot in the case above failed to notify ATC when he experienced icing. Instead, he spent 10 minutes trying to trouble shoot on his own. Perhaps the controllers could've helped route him into a warmer, cloudless area had they known more about his situation.

 

For more tips and tricks about how to prevent icing and what to do if you encounter it, check out AOPA Safety Advisor: Aircraft Icing.

 

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