WASHINGTON, DC – USA
JANUARY 13, 1982
B-737

Scheduled FLT from Washington, DC to Ft Lauderdale, FL. The rwy was closed over 1 hr during moderate to heavy snowfall for snow removal, thus delaying departures. The acft was deiced with a heated ethylene glycol & water solution without engine inlet plugs or pitot static covers installed. Contrary to procedures, reverse thrust was used to help a tug during pushback from the gate and blew snow. After pushback, the flt was delayed 49 min while snow continued in subfreezing conditions. While waiting, the acft was positioned near the exhaust of the acft ahead. During takeoff, the EPR's were set for 2.04, but an anomaly was noted in engine instrument reading. The captain elected to continue takeoff. The acft took off approximately 2000 ft & 15 seconds past the normal takeoff point. After lift-off, it initially climbed, but failed to accelerate. The stall warning stickshaker activated shortly after takeoff and continued until the acft settled, hit a bridge and several vehicles, then plunged into a frozen river. Investigation revealed engine inlet pressure probes became blocked with ice, resulting in a high EPR indication, possible pitch up with snow/ice frozen on wings, no rwy distance markers were available, crew had limited cold weather operational experience.

DRYDEN, ONTARIO – CANADA
MARCH 10, 1989
F-28

The aircraft was fully loaded and had taken on fuel at Dryden. Light snow had been falling whilst the aircraft was being serviced, but the snowfall became heavy while the aircraft waited for take-off clearance, a period of about 10 minutes.

The captain decided to take-off during a snow storm without having the aircraft de-iced. The wings are thought to have been covered with 0.25 to 0.5 inches of snow, whilst the runway was covered with 0.25 to 0.5 inches of slush. The captain believed that the snow was not adhering to the wings and would blow off on take-off. However, the wing contained cold soaked fuel which caused the wet snow on the wings to freeze.

On it's take-off run, the aircraft was reported by witnesses to have labored down the runway, seeming to lack power. Shortly after becoming airborne, the aircraft struck terrain in a wooded area near the runway. The aircraft broke into three pieces and was destroyed by a post accident fire. The FDR and CVR were extensively damaged and the tapes were later found to have melted. Survivors and other witnesses said that the wings had accumulated a layer of wet snow prior to take-off. There were 24 fatalities and 45 serious injuries.

PLATTSBURG, NY – USA
JANUARY 29, 1990
C-208

The pilot overloaded the aircraft by 360 lbs and by 1,100 lbs for flight in icing conditions. The aircraft took off with light wet snow falling, at night. It reached an altitude of 700 ft AGL prior to making a steep descent, striking trees and impacting inverted 1 mile off the end of the runway. Radar data showed the aircraft lift off point and initial climb rate approached that shown in the Flight Manual for short field technique. Snow contamination was found on the top of the wing that did not burn and on the top of the horizontal stabilisers and elevators. Two other Caravans preceded the accident aircraft from the same airport, one 13 minutes prior and the other 3 minutes prior. Radar data showed that they climbed at a slower rate. The accident aircraft had come from a hanger and was not de-iced prior to departure. A pilot flying an identical aircraft with a similar load commented that his climb rate was lower than normal. Another pilot commented that this was the first wet snow of the year and it was sticking to his engine cowling.

DETROIT, MI – USA
MARCH 14, 1997
DC-9

The airplane experienced a partial loss of power on both engines during takeoff. The flight returned and landed without further incident. Post accident examination of the engines revealed the compressor fan blades on both engines had sustained soft body impact damage. The airplane had been subjected to sub-zero temperatures during the previous flight and had landed with the wing tanks almost full. The airplane was on the ground for about two and a half hours prior to the accident takeoff during which time rain was falling. Both the captain and copilot reported that there were no signs of ice on the wings during their early morning preflight

The National Transportation Safety Board determines the probable cause(s) of this accident as follows: The captain’s failure to have the airplane deiced prior to takeoff which resulted in ice ingestion into both engines. Factors associated with the accident were the icing weather conditions, wing ice, an inadequate detection of the ice during the preflight, and the dark lighting conditions when the first officer was performing the preflight.

STOCKHOLM, SWEDEN
DECEMBER 27, 1991
MD-80

The aircraft arrived at Stockholm on the evening before the accident with 5.5 tons of cold soaked fuel (-12ºC) in the wing tanks. The OAT remained around 0ºC all night. There was drizzle followed by light to moderate rain and snow. The maintenance personnel observed clear ice on the wings late at night. The ice was not detected by the morning shift, although the aircraft was de-iced twice shortly before departure.

The aircraft taxied out with the engine and airfoil anti-icing system ON/armed and made a rolling take-off. At lift-off the pilot heard a strange noise above the background noises. Three passengers sitting on both sides of the cabin saw ice fall off the wing and approximately 20 seconds later the crew heard bangs from the right engine and felt vibration. 70 seconds later a left engine fire warning came on and the co-pilot activated the fire extinguisher. Almost simultaneously, at 3,200 ft/196 kts, there was a loss of thrust from both engines and the crew made preparations for a forced landing.

The aircraft broke out of cloud at 800 ft and the pilot aimed for an open field ahead. With the flaps and gear down, the aircraft passed over a ridge, collided with a number of trees, losing the right wing and landed in a field about 6 miles northeast of the airport. The fuselage breaking into three separate parts. It was concluded that the de-icing procedures used had failed to remove clear ice from the wings; and that during the take-off roll, chunks of ice had broken off and had been ingested by the engines, damaging the compressors and causing the engines to surge destructively.

TORINO, ITALY
FEBRUARY 16, 2002
F-70

On February 16, 2002, the flight was scheduled to depart from Caselle Airport in Torino at 05.50 UTC for Schiphol Airport in Amsterdam. During the pre-flight inspection the Captain decided that the aircraft needed to be de-iced. After the de-icing operation the aircraft was visually inspected by the Captain.

During rotation the left engine (No.1) developed fan vibration followed immediately by the failure of the right engine (No.2) at lift off. The crew executed a right hand turn at 1.500 feet QNH and proceeded to a holding fix to prepare for a single engine return to Torino. A PAN PAN PAN call was transmitted. When executing the emergency procedure for the failed engine the first officer could not move the fuel lever to the closed position. Apart from the engine failure, the crew had to deal with an Autothrottle alert, Cabin Pressure alert, Fuel Asymmetry alert, Centre Tank Pumps alert, a Vibration High Engine 1 alert and an Icing alert.

Causes:

--- The crew did not draw the conclusion that the wings were cold soaked and so the formation of clear ice was not suspected. Clear ice was not detected on the upper surface of the wings.

--- Clear ice was not removed from the upper surface of the wings. After the de-icing operation a tactile check was not performed to check for the removal of all ice from the wings.

--- The primary cause of the event was the ingestion of ice by both engines which caused the right engine to fail completely and the left engine to develop high fan vibration.

ANCHORAGE, AK – USA
SEPTEMBER 26, 2004
MD-82

The crew of a McDonnell Douglas MD-82 airplane reported a partial loss of engine power during the takeoff roll. The crew aborted the takeoff, and discovered that the left engine had sustained foreign object impact damage. The airplane had remained parked outside overnight prior to the incident flight, and heavy wet snow/slush was in the parking area and on the taxiway at the time of departure. The captain reported that she did not request to have chemical de-icing done during the preflight, since the outside air temperature was above freezing at the time of departure. The captain reported that there were no signs of ice on the wings during the early morning preflight. A maintenance technician visually inspected both engine inlets for any accumulation of debris prior to departure. The operator's safety officer reported that the crew did not perform a tactile inspection of the upper wing surfaces prior to the incident departure. The MD-80 flight crew operating manual states: "Clear ice can also form on wing upper surface when cold-soaked fuel is in the main wing fuel tanks and the airplane is exposed to conditions of high humidity, rain, drizzle, or fog at ambient temperatures well above freezing." A weather observation at the time of the incident consisted of: Sky conditions and ceiling, 200 feet, few, 600 feet, overcast; visibility, 10 SM; wind, 290 degrees at 8 knots; temperature, 37 F; dew point, 37 F.

The National Transportation Safety Board determines the probable cause(s) of this incident as follows: The loss of engine power due to the flight crew's failure to follow published procedures and directives, and an inadequate preflight inspection, which resulted in ice ingestion into the left engine during the takeoff roll. Factors associated with the incident were icing conditions and ice on the wings.

RENO, NV – USA
JANUARY 15, 1993
C-421

The aircraft was on a flight from Reno, Nevada to Camarillo, California and collided with level ground while attempting to land during a snow shower. The pilot reported an emergency one minute after departing IFR and requested a return to the airport under visual rules. The pilot indicated to ATC that "I can't get any speed". The visibility was variable around the airport with the lowest report of 1/2 mile. Witnesses observed the aircraft travelling fast at low altitude and indicated that both engines were running. Investigations revealed that before the flight, the pitot tube covers were not used. About 1.5 inches of snow had accumulated on the aircraft during the refuelling and was brushed off. The aircraft was seen flying into a snow shower and reversing course. Witnesses reported the aircraft's angle of bank to be 80 to 90 degrees with a 20 degree pitch down attitude. The aircraft descended into a snow covered pasture. Witnesses reported the aircraft levelled it's wings just before impact.

Manufacturers safety and warning supplements indicate in-flight ice protection is not designed to remove snow on parked aircraft. The manufacturer also recommends the use of heated hangers or approved de-icing solutions to ensure that there are no internal accumulations in pitot static system ports.

UNITED KINGDOM
APRIL 4, 2004
BAE-146

In descent from FL270 to FL240 the aircraft became unstable in pitch and would not hold airspeed or altitude. The autopilot and autothrottle were disconnected and the aircraft flown manually. When the autopilot was disconnected the ailerons were found to be jammed, but did eventually move a little with the application of excessive force. No warnings were enunciated but the QRH disconnect drill was actioned. A PAN was declared and, subsequently, an uneventful 24deg flap approach and landing occurred at destination. The ailerons became free at approx 6000ft on the approach. The weather before departure was wet and icing conditions had been encountered just after take-off. The reporter confirms that the aircraft had last been de-iced on 17 Mar 2004. During subsequent inspection large deposits of a "gel-like substance" was found around the ailerons and roll actuator. This was suspected to be de-icing fluid residue. The problem recurred the following day when the ailerons were found to be abnormally heavy and very stiff to operate during descent from approx 10,000ft to 3,000ft, where control feel returned to normal. It was noted that, throughout the flight, the aircraft had been free of cloud/weather and that no control problems were noticed until the autopilot was disconnected. The freezing level was approx 9,000ft and the reporter suspects this problem may have arisen because the autopilot was disconnected above this level.