Accident Case Study: Trapped in Ice

Accident Case Study: Trapped in Ice

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It's the morning of April 16th, 2018, and  a Beechcraft Bonanza, November 9345-Quebec,   is flying IFR over central Ohio. The pilot and  his passenger are en route to Deland Municipal   Airport in Florida. Instrument conditions  prevail in the airplane's current location,   and the Bonanza is accumulating light  rime icing at four thousand feet.   The pilot descends to three thousand feet to  clear the clouds and hopefully eliminate the ice.   Okay we're underneath the clouds right now looks  like it's clearing up. We're about one degree  

over Celsius. November 4-5-Quebec roger thank  you. About one minute later, the controller   notices that the Bonanza has further descended  to two thousand seven hundred feet. November   Four-Five-Quebec, low altitude alert check your  altitude immediately. The MVA in your area is two  

thousand nine hundred. Okay right now we've been  getting some buffeting. We've got some rime ice   but we're losing. November Four-Five-Quebec  roger do you need to land? Uh negative right   now we're - we're clearing up. Roger. We're  about four degrees over Celcius zero now. Roger.   November Four-Five-Quebec uh use  caution the MVA in that area is two   thousand nine hundred. Yeah i understand two  thousand nine hundred Four-Five-Quebec thanks. 

Despite the pilot's assurances, the Bonanza's  descent continues. It's now at 2,200 feet MSL,   only 1,000 feet AGL. November Four-Five-Quebec  how you doing sir? Uh we're doing okay right now.   Waiting for this ice to dissipate. It's the  last transmission the pilot will make to the   controller. A minute later, the airplane's  altitude shows 1,500 feet before it suddenly   disappears from radar. The Bonanza impacts terrain  near the town of Warsaw, Ohio, killing both the  

pilot and his passenger. Sadly, these aren't  the only lives that will be claimed by icing   in the days ahead. A mere 200 miles to the east,  another fatal aviation accident will soon unfold. It's now April 19th, three days later. At  Lancaster Airport in Pennsylvania, a Cirrus SR22,   November 451 Tango Delta, is preparing to  depart on an early morning cross-country   flight to South Bend International Airport in  Indiana. The private pilot and his passenger   are traveling to attend a conference  being held at an Indiana University.  

The pilot obtained a weather briefing using  ForeFlight at 9:27pm the night before,   with a planned departure time of 6:45am this  morning. The graphical forecast products from   his briefing predicted cloud cover as low as  2,000 feet MSL (around 800 – 1000 feet AGL)   along the route of flight, and the surface  forecast predicted marginal VFR conditions   with likely snow shower activity. Meanwhile,  terminal forecasts for several airports along   the route of flight called for IFR and low IFR  conditions during the airplane’s passing time.   The ForeFlight briefing also included AIRMETs  for IFR conditions, mountain obscuration, and   moderate icing at various levels. However, these  AIRMETs were only valid until 5:00am on April 19,   which was before the intended departure  time. After receiving the weather briefing,  

the pilot filed an IFR flight plan with a  planned cruising altitude of 6,000 feet MSL.   Now, at 7:34am, the Cirrus begins its departure.  The 500 hour pilot is instrument-rated and   current, with 28 hours of actual IMC logged.  In the last six months, he's flown four   flights with his instructor for the purpose of  maintaining instrument currency and proficiency.  

Although last night's weather briefing warned  of unfavorable conditions along his route,   the pilot has decided to proceed with the trip.  However, there's a troubling omission in his   flight planning. An updated AIRMET advisory was  recorded via the flight plan identification number   at 4:52am, but there is no record that  the pilot retrieved this new information.   If he had obtained an updated briefing, he  would see that hazardous conditions are now   active during the time he'll be passing through.  The new AIRMETs warn of moderate icing between the   freezing level and 16,000 feet, IFR and mountain  obscuration, and low-level turbulence, valid   until 11:00am. Unfortunately, this Cirrus is not  equipped with an anti-icing or de-icing system.  

The pilot and his passenger, unaware of the  new weather information, set off for Indiana. It's now an hour later. Cirrus 451 Tango Delta  is about 10 miles past the city of Altoona,   Pennsylvania, cruising at 5,500 feet,  when the pilot makes a call to ATC.  

Johnstown, this is Cirrus 4-5-1-Tango-Delta with  a request. Cirrus 1-Tango-Delta, say request. Ah,   just curious you know - if you know  what the tops are of, of the clouds?   I do not have any tops reports. Stand by. Let me  call Center and see if they have any of that area. Okay, 1-Tango-Delta, Center has a tops  report about 25 northwest of your position,   around 17,000. 17,000 is the tops of the ceiling?  Clouds? Ah, yeah. They said that that was, that  

was the tops in that area. All right. We were just  in a lot of IMC. What's the bottom? Is it 4,000?   It could be lower than that. I'm showing, here  at Johnstown, which is 18 miles southwest of you,   we have - our, our cloud deck starts at 200 feet.  All right. That doesn't help me. A minute later,  

the reason for the pilot’s request to ATC becomes  more clear. Johnstown, this is 4-5-1-Tango-Delta.   Say again? This is Cirrus 4-5-1-Tango-Delta.  We're getting a little ice up here. I think   I should probably get down to Johnstown. Okay. So  you want to divert to Johnstown, is that correct?   Yes, sir. Can you vector me? 1-Tango-Delta,  affirmative, sir. You're clear to Johnstown   via radar vectors. It'll be an ILS runway 3-3  approach. Turn left, heading of 1-6-0. Actually,   correction, make it 1-7-0 heading vector to  the ILS. 1-7-0. And if you get the chance,  

the type of icing you're getting, the intensity,  and the outside air temperature, please?   It's a little, it's a little - not bad, but  it's enough to get me a little concerned.   Copy that. Thank you. The pilot’s conversation  with ATC indicates that he understands the   severity of the situation, and he has decided his  best course of action is to get on the ground.   What runway am I expected to go into, Johnstown?  1-Tango-Delta, it's runway 3-3, the ILS, and we   are, we are having traffic information Uniform.  And we're showing a ceiling at 200 overcast, so   that's right at the mins there for the ILS. If you  still want to try it, that's fine. If not, I am   showing Altoona's weather is a little bit better.  They report -- or they're showing 500 overcast  

right now. All right. Let's go to Altoona. With  Altoona looking like the better option, the pilot   alters his course. The airport is 25 miles to the  southeast. 1-Tango-Delta, roger. Does ILS 2-1 work   for you? That'd be good. What - can you vector  me that? Yep. Absolutely. 1-Tango-Delta, continue   left turn, heading 1-0-0 vector to ILS. 1-0-0.  Think I could get down to 4,000? 1-Tango-Delta,   descend and maintain 4,500. That'll be  the lowest I can get you for a little bit.  

4,500. Cirrus 1-Tango-Delta, advise when you do  have the weather and NOTAMs at Altoona. And if you   need me to, I can read the weather for you there.  I can read the earliest observation for them.   Yeah, if you could read the weather, that'd  be great.1-Tango-Delta, not a problem, sir.   The 1-2-2-6 Zulu observation: Winds 3-6-0  at 6; visibility 1 mile; light rain, mist;   ceiling is 500 overcast; temperature 6; dew point  4; and the Altoona altimeter is 2-Niner-7-0. What  

information is that? That's just off the  ASOS there. It's an uncontrolled airport.   Within the next minute, the controller notices the  Cirrus changing its heading. 1-Tango-Delta, I show   you turning about a 200 heading right now. Say  intentions. I'm just going to try to get direct.   What direction should I be? A heading of 0-Niner-0  when able. 0-Niner-0. Yep. I'll get it back on.   Meanwhile, N451TD has been steadily  descending past 4,500 feet. The Cirrus is at   3,900 feet when the pilot checks in. And you  want me at 4,500? 1-Tango-Delta, affirm, sir.  

Altitude 4,500 on heading of 0-Niner-0. A minute  later, the controller notices that the Cirrus is   still at 3,900 feet. Cirrus 1-Tango-Delta,  the altimeter is 2-Niner-7-0. Just verify   you're level at 4,500, please. All right. 4,500.  I just dropped a little bit. I'll get it back up.   Okay. Thank you, sir. It’s now 2 minutes later,  and the pilot has only climbed to 4,100 feet.   If his climbing difficulty is indicative of  structural icing, the pilot hasn’t mentioned it   to the controller. 1-Tango-Delta, turn 10 degrees  to the left. 10 degrees left. 4-5-1-Tango-Delta.  

Attention all aircraft, new Johnstown altimeter  2-Niner-7-1. Cirrus-1-Tango-Delta, turn right,   heading of 1-2-0. 1-2-0. 4-5-1-Tango-Delta.  The Cirrus continues to remain below its   designated altitude, averaging 4,100  feet over the previous few minutes.   Cirrus 1-Tango-Delta, 5 miles  from (indiscernible). Turn right,  

heading 1-8-0. Maintain at or above 4,300 till  you're established. Clear to ILS 2-1 Altoona.   All right. 4-5-1-Tango-Delta turn right  to 1-8-0. We're clear for the intercept.   Two minutes pass, and the controller  sees that N451TD has crossed through   the localizer course for runway 21 at  Altoona. The pilot hasn’t realized the error.  

4-5 - 4-5-1-Tango-Delta, you've already begun  through the localizer, sir. Say intentions.   Um, I still want to get there. Can you vector me  one more - vector me one more time? 1-Tango-Delta,   affirmative, sir. Maintain 4,500. Turn left  heading 0-9-0. It'll be a box pattern back to   final. 0-9-0, okay. I missed it. The pilot turns  left, but continues his left turn beyond 0-9-0.  

39 seconds into the turn, the Cirrus  begins to descend and its airspeed   increases. About 10 seconds later, the left  turn tightens and the airplane begins to spiral.   The Cirrus impacts the ground  in a steep, nose-low attitude. Cirrus 4-5-1-Tango-Delta radar contact lost. Cirrus 4-5-1-Tango-Delta, Johnstown  Approach. How do you hear me? A review of weather information current at the  time of the flight revealed that the Cirrus most   likely encountered IMC about 500 feet AGL on  the initial climbout from Lancaster Airport,   and remained in IMC and conditions favorable  to icing for the rest of the flight. Before the flight, a forecast icing potential  indicated that light-to-moderate intensity   icing existed near the accident site,  and a current icing potential product   indicated that supercooled liquid droplets  existed near the accident site. This weather  

information was available in addition to the  updated AIRMET advisory issued at 4:52am. The NTSB could not determine to what degree   the Cirrus was affected by structural  icing during the approach to Altoona.   At minimum, it appeared to affect the airplane’s  ability to maintain the altitude requested by ATC. In the end, however, icing was only one part  of this fatal accident. While the pilot was  

maneuvering in the last seconds before the  crash, he was in IMC with restricted visibility.   Combined with the spiraling radar track data  and the high-velocity impact with terrain,   the circumstances indicated the pilot was  likely experiencing spatial disorientation.   The airplane’s entry into a descending left turn  while the pilot was being vectored back toward the   localizer course, which subsequently tightened,  became what’s known as a graveyard spiral.  

The graveyard spiral can occur  from a vestibular illusion   associated with a return to level flight  following a prolonged banked turn. There are a number of lessons that we can learn  from this accident. The first and most obvious   is that it’s imperative to check the most recent  weather conditions before departing on any flight.   A study of the forecast the night before  a cross country is always a good idea, but   it’s only one part of safe and thorough preflight  planning. Weather is dynamic and ever-changing,   and many aviation forecasts are updated every 6  hours, including AIRMETs and terminal forecasts.   Flying with outdated information from a forecast  10 hours old is asking for trouble. Furthermore,  

with the weather information he reviewed the night  before, the pilot already knew about hazardous   weather to come, and shouldn’t have proceeded  with hope that conditions would get better.   After all, hope is not a strategy for flying  safely. A past-present-future approach can be   helpful in identifying and predicting weather  trends. For example, where was the weather   yesterday or several hours ago? How long did it  take to reach its current condition and location?   And based on that, when can I expect it  to improve (or worsen) along my route? Another critical lesson is the  need to tell ATC what’s going on.  

As the icing accumulated and the reality  of the dangerous situation set in,   small clues in the pilot’s language and actions  were possible hints of his growing unease. It's a little, it's a little -- not bad, but  it's enough to get me a little concerned. Think I can get down to 4,000? 1-Tango-Delta, I show you turning about  a 200 heading right now. Say intentions. I'm just going to try to get  direct. What direction should I be? It appears that the pilot desired a lower  altitude with hope of finding higher temperatures.  

It also seems that he knew he needed to  expedite his approach to the airport,   indicated by his intentional, albeit  unapproved, change in heading. After the   controller told him that 4,500 feet was  the lowest altitude he could authorize,   and questioned his heading change to 2-0-0, the  pilot should have countered with more assertive   language to make it clear what he needed. For  example, “I need to get out of icing conditions,   I need the lowest possible safe altitude, and  I need the most direct course to Altoona.”  

Going one step further and declaring an  emergency would have been entirely appropriate. The high workload and stress the pilot  was likely experiencing appears to have   contributed to his failure to intercept the  localizer course for Runway 2-1 at Altoona.   It’s difficult to say whether the missed  intercept had more to do with the icing conditions   or the pilot’s instrument proficiency. Shortly  following was the onset of spatial disorientation.   The pilot’s spiraling turn and subsequent crash  is a stark reminder of the insidious nature of   spatial disorientation. It can affect any pilot,  even one who is instrument-rated and current.  

While some details of the pilot’s IFR  refresher flights in the previous six   months were published by the NTSB, we don’t know  their true impact on the pilot’s proficiency.   It’s important that instructors customize  training to suit pilots’ individual needs   and types of flying, especially during  seasons of cold, snow, and icing.   CFIs should conduct risk-management training  using real-world scenarios to improve pilots’   decision making. This is an important component  of the FAA’s Airman Certification Standards. We also don’t know how reliant the pilot was on  using the autopilot in the Cirrus. The radar data   showed that the airplane was flying a relatively  smooth and consistent flightpath that was   indicative of the pilot using the autopilot for  the majority of the flight, until the final turn   after flying through the localizer course. Another  suggestion for instructors is to encourage the  

practice of periodically hand-flying the airplane,  to keep a pilot’s stick and rudder skills sharp. Finally, a small detail discovered during the  post-crash investigation proved troubling.   The NTSB found that the pilot had  not removed the safety pin for the   Cirrus Airframe Parachute System before flight.   Removing this safety pin is critical to ensure  proper operation of the parachute system.   This is a standard Cirrus checklist item, and it  appears three times – remove the pin during the   preflight walk-around, verify it is removed before  engine start, and verify once more before takeoff. We don’t know if the pilot attempted  to pull the parachute before the crash,   but if he had, it could have been a life-saving  maneuver had the pin been properly removed.

The crash of November 4-5-1-Tango-Delta, as  well as the loss of two lives in November   9-3-4-5-Quebec a few days earlier, is a sad and  sobering look at the hazardous nature of icing,   and the effects it has on both the aircraft and  pilot. In the Bonanza accident, the pilot failed   to obtain an official weather briefing. In the  Cirrus accident, the pilot neglected to obtain   an updated briefing. It’s a reminder to us  that in general aviation, weather is one of   the largest factors determining the safety  of a flight. In today’s flying environment,  

new technologies provide near real-time weather  observations that can help us use the most   complete information available to optimize our  decisions. If we don’t use all of the tools at our   disposal to make a full assessment of the weather,  we put ourselves and our passengers at risk.

2021-01-17 00:05

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