June 8, 2022

Incident at 4858N / 08811W (Weather balloon, meteor, rocket, CIRVIS/UFO)

An Air Canada Airbus A330-343 (C-GEGP/ACA322) from Calgary, AB (CYYC) to Montreal/Pierre Elliott Trudeau, QC (CYUL) reported a green flash descending through their altitude of FL410. The pilot suspected it might be a meteorite. The controller questioned if it may have been lightning or St. Elmos fire. The pilot responded in the negative.

March 3, 2022

Incident at 60NM E Red Bluff, CA (KRBL)

Aviation Incident Report: Oakland air route traffic control center (ARTCC) reported that the cockpit of an Air Canada Boeing 737 MAX 8 (ACA558) from Vancouver, BC (CYVR) to Los Angeles, CA (KLAX) was illuminated by a green laser at the 3 oclock position while south-southeast bound at FL410, 60NM East of Red Bluff, (KRBL). No injuries reported. Modoc County Sheriff notified.

April 27, 2022

Incident at BIBEM intersection (Communication navigation surveillance/air traffic system)

A Sun Country Inc. Boeing 737-800 (N7949A/SCX3052) from Fairbanks, AK (PAFA) to Spokane, WA (KGEG) reported at BIBEM at FL410 and the KD controller had no estimate on this aircraft.

April 15, 2022


A Sunwest Aviation Ltd. Learjet 45 (CNK645) from Vancouver, BC (CYVR) to Lethbridge, AB (CYQL) departed FL410 without a clearance, climbed to FL413 and then descended to FL406. CNK645 halted descent before separation was lost with a British Airways 787-10 (BAW49) from London/Heathrow, United Kingdom (EGLL) to Seattle-Tacoma, WA (KSEA). No impact to operations. (This record replaces CADORS 2022P0530, which was deleted due to incorrect region)

March 9, 2022

Incident at 131NM CALGARY INTL AB (CYYC)

A United States Air Force Air Mobility Command Boeing KC-135R (RCH793) from Fairchild/Air Force Base, WA (KSKA) to Royal Air Force Mildenhall, United Kingdom (EGUN) requested descent from FL410 to FL250 due to a pressurization issue. No emergency declared. No assistance required. No impact to operations.

March 5, 2022

Incident at CHAPO intersection

A Delta Air Lines Airbus A350-900 (DAL8965) from Fairbanks, AK (PAFA) to Detroit/Wayne County, MI (KDTW) was flight planned to enter the Edmonton (EG) airspace at CHAPO at FL410. The aircraft checked-in at CHAPO through FL400 and climbing to FL410. No impact to operations.

June 25, 2022

Incident at 4800N / 04000W

A Superior Transportation Associates Inc. Gulfstream G-IV (KFB211) from Teterboro, NJ (KTEB) to Ibiza, Spain (LEIB) was given oceanic clearance for FL410. The aircraft was flight planned to climb to FL450 at 40W. When the aircraft went by 40W, it climbed without oceanic clearance to FL450.

June 15, 2022

Incident at 4431N / 04800W

New York coordinated FL390 for a Royal Air Maroc Boeing 787-9 (RAM208M) from Casablanca, Morocco (GMMN) to Montreal/Pierre Elliott Trudeau, QC (CYUL), and the aircraft reported at FL410. No traffic. The aircraft was subsequently cleared to FL410. No impact to operations.

March 25, 2022

Incident at 4600N / 05924W

Severe (SVR) turbulence was reported by a MHS Aviation GMBH Bombardier BD-700-1A10 (MHV1B) from Toronto/Lester B. Pearson, ON (CYYZ) to Venice/Marco Polo, Italy (LIPZ) at FL430. The aircraft moved to FL410, no injuries or damage reported. The London (XU) flight information centre (FIC) was notified.

March 27, 2022

Incident at 4540N / 03806W

A VistaJet Ltd. Bombardier BD-700-1A10 (9HVJK/VJT836) from Farnborough, UK (EGLF) to Nassau, Bahamas (MYNN) encountered turbulence at FL430 and was unable to maintain cleared altitude. Conformance alerts received advising of the flight descending through FL427, FL424 and FL410. Flight was queried and advised they were descending to FL410 due weather and requested FL410 and deviation left 20NM or right 50NM of track. Flight was re cleared as requested. Crossed the Gander/New York (CZQX/KZNY) boundary at 2316Z. No impact to operations.

June 25, 2021

Incident at 4921N / 06241W

A Helidosa Aviation Group Gulfstream Aerospace Gulfstream IV (HI1055) from Teterboro, NJ (KTEB) to Reykjavik/Keflavik, Iceland (BIKF) was issued oceanic clearance to climb to FL430 from LOMSI. The aircraft began its climb prior to LOMSI. The controller re-cleared the aircraft to FL410 and advised the pilot that they would receive further instructions from Gander. No operational impact. No loss of separation.

October 12, 2021

Incident at 67NM PORT HARDY BC (CYZT)

A Philippine Airlines Airbus A350-900 (RPC3504/PAL116) from Manila, Philippines (RPLL) to Vancouver, BC (CYVR), descending from FL410 to FL390, received a traffic alert and collision avoidance system (TCAS) resolution advisory (RA) in reference to an American, corporately registered Bombardier CL-600-2B16 (N117AA) from Portland/Hillsboro, OR (KHIO) to Juneau, AK (PAJN), at FL380.

September 2, 2021

Incident at In the vicinity of: VANCOUVER CENTRE / ACC DE VANCOUVER (Communication navigation surveillance/air traffic system)

An American corporately registered Textron Aviation Inc. (N585QS) from Boeing Field/King County, WA (KBFI) to Sitka, AK (PASI) was cleared to FL400. Upon checking in with Vancouver Center, the controller missed that the flight crew provided cleared altitude of FL410. When the aircraft was climbing through FL405, the controller queried and had the aircraft return to FL400. No operational impact.

June 7, 2021

Incident at 5300N / 09430W

A Cat Aviation Dassault Falcon 7X (HBJSS/CAZ601) from Los Angeles/Van Nuys, CA (KVNY) to Oberpfaffenhofen, Germany (EDMO) was cruising at FL410 when the pilot reported moderate to severe turbulence. Thunderstorm activity was present in the area. No action was taken, no impact to operations.

September 12, 2021

Incident at JAGIT intersection

An American corporately registered Gulfstream G280 (N463SD) from Anchorage, AK (PANC) to DuPage/West Chicago, IL (KDPA) was coordinated verbally by PANC at FL410 at 1849Z. The aircraft reported over JAGIT at 1902Z at FL450. No impact to operations.

September 20, 2021

Incident at 4749N / 05838W

A Lufthansa German Airlines Airbus A350-900 (DLH411) from New York/John F. Kennedy Intl, NY (KJFK) to Munich, Germany (EDDM) reported severe turbulence at FL410. The aircraft requested to descend to FL390. No reported injuries or impact to operation. London (XU) flight information centre (FIC) advised.

March 28, 2021

Incident at 4728N / 06034W

A Wamos Air Airbus A330-200 (PLM934P) from Toronto/Lester B. Pearson, ON (CYYZ) to Madrid–Barajas, Spain (LEMD) reported severe turbulence at FL410 and FL400. No impact on operations.

October 15, 2020

Incident at VERTI intersection

A strong and clear emergency locator transmitter (ELT) was heard by a Government Of Canada, Department Of National Defence Airbus A310 (HUSKY84) from Trenton, ON (CYTR) to Trenton, ON (CYTR) at FL310, and a WestJet Boeing 737-6CT (C-GEWJ/WJA248) from Toronto/Lester B. Pearson, ON (CYYZ) to Halifax/Stanfield, NS (CYHZ) at FL410. No impact to operations.

April 22, 2020

Incident at 5218N / 10500W

Emergency Locator Transmitter (ELT) activation reports were received from multiple aircraft that were between FL250 and FL410, Eastbound, beginning approximately 35NM East of Saskatoon/John G. Diefenbaker, SK (CYXE): a Government of Canada, Department of National Defence Airbus A310 (CFC4168) from Edmonton, AB (CYEG) to Trenton, ON (CYTR); a Sunwest Aviation Ltd. Learjet 45 (C-GVVZ) from Edmonton, AB (CYEG) to Winnipeg/James Armstrong Richardson, MB (CYWG); and a Jazz Bombardier CL-600-2D24 (JZA8628) from Saskatoon/John G. Diefenbaker, SK (CYXE) to Toronto/Lester B. Pearson, ON (CYYZ). The Joint Rescue Coordination Centre (JRCC) Trenton was notified. No operational impact.

January 23, 2020

Incident at 195NM NE ST. JOHN'S INTL NL (CYYT)

At time 2202Z and just west of 50N050W, a British Airways Boeing 787-9 (GZBKD/BAW293) on a flight from Heathrow/London Intl, UK (EGLL) to Washington/Dulles, VA (KIAD) declared a PAN PAN due to a pressurization issue and requested descent from FL410 to FL350. The flight was recleared to FL340. BAW293 reported the situation good at FL340 and PAN PAN cancelled at 2215Z. Flight continued to its destination and exited the Gander Intl, NL (CYQX) flight information region (FIR) at 2248Z.
UPDATE TSB Report #A20A0006: G-ZBKD, an Boeing 787-900 operated by British Airways, was conducting flight BAW293 from London Heathrow Intl. (EGLL), UK to Washington Dulles Intl. (KIAD), VA. The aircraft dispatched with the right air conditioning pack inoperative in accordance with the MEL. During the cruise portion while at FL410, the left air conditioning pack failed, resulting in a PACK ALTITUDE LIMIT warning. The checklist required a descent to FL340. At 195 nm NE of St John’s International Airport, NL (CYYT), the crew requested FL340, however it was denied by ATC. The crew then declared a PAN-PAN due to the pressurization issue and a descent to FL340 was made. Once the aircraft reached FL340, the crew reported the situation was normal and cancelled the PAN-PAN and continued to destination without incident.

January 9, 2020

Incident at 5038N / 03215W

A Dassault Falcon 2000 registered to the Isle of Man (MAERO) on a flight from Pittsfield, MA (KPSF) to Farnborough, UK (EGLF) was observed climbing to FL418 prior to descending to its cleared altitude of FL410. No traffic. No impact on operations.

October 17, 2019

Incident at 5135N / 06705W

A Norwegian Air Shuttle Boeing 787-9 (LNLNX/NAX7744) on a flight from Los Angeles Intl, CA (KLAX) to Madrid, Spain (LEMD) reported moderate to severe turbulence at FL410. The aircraft descended to FL370.

August 25, 2019


As of 1800Z, numerous emergency locator transmitter (ELT) signal reports were received from all sectors around Toronto/Lester B. Pearson International Airport, ON (CYYZ), from all altitudes between FL410 to 2000 ft on approach. These reports were too numerous to document. The Joint Rescue Coordination Centre (JRCC) Trenton was advised, and finally, after being unable to identify the source, JRCC Trenton decided to dispatch a Cessna C337 Skymaster off St. Catharines/Niagara, ON (CYSN), in an attempt to locate the source. No operational impact.

April 4, 2019

Incident at 4839N / 09119W

A WestJet Boeing 737-700 (WJA656) from Calgary, AB (CYYC) to Toronto/Pearson, ON (CYYZ) was observed climbing without a clearance. The aircraft left the cleared altitude of FL390 and reached FL410. When queried, the aircraft descended to FL390 and indicated having lost reduced vertical separation minimum (RVSM) certification. No other aircraft in the vicinity and no impact to operations.

April 16, 2019

Incident at 5800N / 03654W

A Virgin Atlantic Airways Boeing 787-9 (GVBEL/VIR20V) from San Francisco, CA (KSFO) to London, UK (EGLL) declared PAN PAN due pressurization issues, requested lower, and was cleared lower. No traffic or impact to operations.
Update TSB #A19A0020: G-VBEL a Boeing 787-9 aircraft operated by Virgin Atlantic, was conducting flight VIR20 from San Francisco Intl (KSFO), CA to London/Heathrow (EGLL), UK. During cruise flight, the flight crew initiated a climb from FL390 to FL410. The flight crew noted that the cabin altitude started to rise at a rate of 600 feet per minute, deviating from the normal 6000 feet. Manual cabin pressure control was selected, and a PAN PAN was declared. The flight crew elected to descend back down to FL390. The aircraft had been dispatched under Minimum Equipment List (MEL) provision for an inoperative Cabin Air Compressor (CAC) on the left air conditioning pack. Section 2 of the B787 MEL notes that the cabin altitude, which is normally 6000 feet, may rise to 8000 feet with an inoperative pack or CAC in degraded operations. After review of this section of the MEL, the flight crew continued to destination without further incident.

August 19, 2019


At 0109Z, a Trans-Exec Air Service, Inc. Gulfstream GV (N619GV) from Westchester County, NY (KHPN) to Catania, Italy (LICC) descended from FL410 to FL407 and then climbed up to FL412. The controller confirmed the FL with the aircraft (FL410). The data systems coordinator (DSC) was investigating possible radar issues. No impact on operations, safety not jeopardized.

June 20, 2019

Incident at 4834N / 06021W

A Fox Flight Learjet 45 MEDEVAC (C-FEMF) from Toronto/Lester B. Pearson, ON (CYYZ) to Deer Lake, NL (CYDF) observed descending without air traffic control (ATC) clearance. When queried, the pilot advised they were aware and were correcting back to cleared altitude. The aircraft was cleared at FL410, descended to FL405 before correcting back to FL410. No loss of separation or impact to operation.

June 2, 2018

Incident at 6350N / 06720W

After having received and correctly read back clearance for FL410, an American, corporately owned Gulfstream GV (N123FT) from San Francisco, CA (KSFO) to London, UK (EGSS) was seen at FL450. No impact on operations.

December 5, 2018

Incident at 13NM NANAIMO BC NDB (YCD)

An Alaska Airlines Boeing 737-700 (N611AS/ASA64) from Ketchikan International, AK (PAKT) to Seattle-Tacoma International, WA (KSEA) initiated an emergency descent from FL410 at 0356Z due to rapid decompression. The aircraft declared an emergency at 0358Z. The aircraft levelled off at 10000 feet at 0402Z, and exited the Canadian airspace at 0406Z. No operational impact.
Update TSB Report #A18P0170: N611AS, a Boeing 737-700 aircraft operated by Alaska Airlines, was conducting flight ASA64 from Ketchikan Intl (PAKT), AK to Seattle-Tacoma Intl (KSEA), WA with 5 crew members and 37 passengers on board. During cruise flight just prior to the top of descent at KSEA, the flight crew felt a pressure change in their ears. The cabin altitude panel was observed climbing at 3000 feet per minute. Within 10 seconds, the cabin altitude warning horn activated. The flight crew donned their oxygen masks, declared an emergency, and initiated a rapid descent. The aircraft was leveled off at 10 000 feet ASL, and the flight continued to its destination where it landed without further incident.

October 22, 2018

Incident at Seattle

TSB #A18F0249: C-FMPN, an Embraer EMB-505 300 Phenom aircraft operated by Aurora Jet Partners, was conducting a flight from Vancouver Intl (CYVR), BC, to Scottsdale (KSDL), AZ with 2 crew members and 2 passengers on board. During the climb from FL390 to FL410 south of the SEA VOR, the flight crew was alerted to multiple BATT EXCEEDANCE CAS messages that remained on briefly, and then extinguished. The messages appeared for a third time, and remained on. The flight crew requested a diversion to Yakima Air Terminal/McAllister Field (KYKM), WA, and declared a PAN PAN. A normal approach and landing on Runway 27 was conducted at KYKM without further incident, with ARFF standing by. As a precaution, ARFF scanned both aircraft batteries with a Thermal Imaging Camera (TIC), and no abnormal heat signatures were detected. Maintenance personnel replaced the number 1 Starter/Generator and the number 1 Generator Control Unit. Function tests were completed with no faults found and the aircraft was returned to service.

September 24, 2018


UPDATE from Airworthiness: A Civil Aviation Safety Inspector (CASI) looked into this occurrence. Maintenance action: Cabin window assy at row 9DEF was replaced as per Aircraft Maintenance Manual (AMM). Cabin pressure leak test performed. No further occurrence reported since then.
The Crew of a Sunwing Airlines Inc. Boeing 737-8DC (C-FJVE) from Poznan, Poland (EPPO) to Alicante-Elche, Spain (LEAL) decided to divert to Katowice, Poland (EPKT) because of formed condensation and loud squeal coming from passenger window 9F. This happened 5 minutes after reaching FL410.

July 2, 2018

Incident at 6221N / 11252W

Controller sent a controller-pilot data link communications (CPDLC) message asking what time an Air Transat Airbus A330-243 (C-GUFR/TSC255) from Manchester, UK (EGCC) to Vancouver Int'l, BC (CYVR) was able to go to FL410. TSC255 responds "We can accept FL410 at 1641Z" and the aircraft started the climb to FL410. No impact to operations.

May 31, 2018

Incident at 43NM GRANDE PRAIRIE AB (CYQU) (Communication navigation surveillance/air traffic system)

An American, corporately registered Dassault Falcon 2000EX (N885A) from Grande Prairie, AB (CYQU) to Minneapolis/St. Paul International, MN (KMSP) was cleared by the Controller to a FL410 in an adjacent sector without coordination. No impact on operations.

May 14, 2018

Incident at 5545N / 10200W (ATM - inaccurate aeronautical information)

A LOT Polish Airlines Boeing 787-8 (SPLRD/LOT23) from Warsaw, Poland (EPWA) to Los Angeles Int'l, CA (KLAX) requested FL410, and was told to standby. The aircraft acknowledged standby. Two minutes later on a separate frequency, An American corporately registered Gulfstream GVI (G650ER) (N358V) checked in at FL410. The controller acknowledged N358V and said "loud and clear FL410". The controller then started transmitting to a different aircraft as LOT23 replied "thank you". LOT23 then started to climb to FL410. No loss of separation occurred.

February 19, 2018

Incident at 4931N / 11432W

A Pro Airways Dassault Falcon 2000 (MMN48) on a flight plan from Cranbrook/Canadian Rockies Int'l, BC (CYXC) to Buffalo Int'l, NY (KBUF) was in the climb to FL410. At 1802Z, the aircraft descended on its own due to a pressurization issue. Air Traffic Control (ATC) subsequently cleared the flight to descend to FL200. No emergency declared. No impact to the operation.

October 5, 2018


Severe turbulence at FL430 was reported by an American, corporately registered Gulfstream GV (N808JG) from West Palm Beach, CA (KPBI) to Santorini (Thira), Greece (LGSR). The aircraft descended to FL410 and reported that it was smooth. No damage or injuries were reported. The Halifax Flight Information Centre (FIC) was advised.

May 22, 2018

Incident at 4912N / 04906W

An American corporately registered Learjet 36A (N41GJ) from Bangor Int'l, ME (KBGR) to Shannon, Ireland (EINN) passed 50W at 0128Z at FL410. At 0133Z, it requested a lower level due to warm temperatures. At 0134Z, it indicated while in descent that it was unable to maintain FL410. At 0134Z, the aircraft advised the next lower level was FL320. The aircraft reported offsetting and that it was descending to FL320. At 0146Z, the aircraft reported its level at FL320. Multiple pieces of traffic were at all levels on Track W. Prior to entering the ocean, the aircraft was advised that lower levels were available with a re-route.

May 16, 2018

Incident at 4636N / 05810W

Severe turbulence at FL410 reported by a Gestair S.A. Gulfstream Aerospace Gulfstream 5 G-1159D (GES251) from Detroit Metro/Wayne County, MI (KDTW) to Madrid/Bajaras, Spain (LEMD) descended to FL390. Halifax (HZ) Flight Information Centre (FIC) was advised.

Incident at 4518N / 06111W

Moderate to severe turbulence was reported by a foreign-operated Bombardier BD-700-1A11 (MGRAN) from Teterboro, NJ (KTEB) to London/Biggin Hill, UK (EGKB) that was climbing from a flight level of 41,000 feet (FL410) to a flight level of 43,600 feet (FL436). The Halifax (HZ) Flight Information Centre (FIC) was advised.

August 19, 2017

Incident at 6400N / 05000W (Communication navigation surveillance/air traffic system)

A United Airlines Boeing 787-9 (N29961/UAL990) on a flight from San Francisco, CA (KSFO) to Paris, France (LFPG) was provided an oceanic clearance at FL410 and via flight plan routing. The flight was unable to climb to cleared level and requested FL390. A new clearance was provided at the requested level and with a reroute. The routing that RK expected and the flight's cleared route were different.

November 18, 2017

Incident at 5000N / 04000W

At 0740Z, a Malta registered Cessna 750 (9HELI) on a flight from St. John's, NL (CYYT) to Brescia, Italy (LIPO) gave a 40W position report which was 30 minutes overdue due to poor high frequency (HF) conditions. The flight reported at FL450 although oceanic clearance was for FL410. The aircraft stated that they understood clearance was to be level at FL450 by 0640Z and that HF was very poor.

August 11, 2017

Incident at 4748N / 05758W

An Aeromexico Boeing 787-8 (AMX007) on a flight from Mexico City, Mexico (MMMX) to London, England (EGLL) was at FL390 and issued an oceanic clearance electronically. Ocean clearance was for FL410 at OEP ELSIR. The flight was noticed climbing without a clearance from air traffic control (ATC). The flight was queried and the controller advised that an oceanic clearance is not approval to climb. The flight was issued a clearance to FL410 and coordinated with the Gander, NL (QX) controller.

May 13, 2017

Incident at In the vicinity of: RIKAL intersection

An Image Air Charter Dassault Mystere Falcon 900 (C-FWKX) on a flight from Toronto/Lester B. Pearson, ON (CYYZ) to Glasgow, Scotland (EGPF) was given an oceanic clearance of RIKAL maintain FL410. The aircraft began to climb about 230NM west of RIKAL. No impact on the operation and no other aircraft were impacted.

March 7, 2017

Incident at 180NM W PELTU intersection

At 0720Z, A Norwegian Air Boeing 787-8 (LNLNG/NAX7006) from New York, NY (KJFK) to Stockholm, Sweden (ESSA) was climbing from FL390 to FL410 without a clearance from the radar controller. The flight had previously received an oceanic clearance for FL410. No traffic.

Incident at 30NM W EMBOK intersection

At 0711Z, an Aer Lingus Airbus A330-200 (EIDAA/EIN146) from San Francisco, CA (KSFO) to Dublin, Ireland (EIDW) climbing from FL390 to FL410 without a clearance from the radar controller. The flight had previously received an oceanic clearance for FL410. No traffic.

February 20, 2017

Incident at 4718N4743W

A Mexican commercially registered Embraer E135 from Gander, NL (CYQX) to London Stansted, UK (EGSS) was observed on radar descending from FL410 to FL400 at approximate position 4718N04743W. The aircraft was queried and advised descent was due to turbulence. Another flight, a Norwegian Air Boeing 787-8 (LNLNB/NAX7036) from Fort Lauderdale, FL (KFLL) to Stockholm, Sweden (ESSA) on a crossing route at FL400 was descended to keep clear of flight in turbulence. The aircraft were approximately 40 NM apart at their closest. Both flights were returned to original flight levels at 0651Z.

February 6, 2017

Incident at 30 NM W NANSO intersection

At 1729Z communication was lost with a Executive Jet Gulfstream Aerospace IV (EJM9) from Charlotte, NC (KCLT) to Dublin, IE (EIDW) while the aircraft was being handed off to Gander area control centre (ACC). Contact was reestablished at 1733Z after numerous attempts. The aircraft reported leaving FL390 climbing to FL410.

November 7, 2016

Incident at In the vicinity of: PIKNA Intersection (Communication navigation surveillance/air traffic system)

A United Airlines Boeing 787-8 (UAL47) from Frankfurt, Germany (EDDF) to Houston, TC (KIAH) made initial contact with Moncton area control centre (ACC) at FL390, requesting FL410. The controller issued a climb to FL400. The pilot read back the climb clearance to FL410 which was not corrected by the controller. The flight reached FL410 when the controller noticed the error and re-cleared the flight to FL400. No traffic was present.

September 15, 2016


A 650584 Alberta Inc. Learjet 36A (C-FCLJ) from Hamilton, ON (CYHM) to Keflavik, Iceland (BIKF) reported having difficulty maintaining altitude due to aircraft performance and asked for a block between FL405 and FL410. The aircraft was told to standby and was them observed descending through FL407. The aircraft was then cleared to FL400. No impact on the operation and no other aircraft in the vicinity.

July 8, 2016

Incident at 4808N/07119W (ELT)

An emergency locator transmitter (ELT) signal was reported in the non-directional beacon (NDB) area at Bagotville (YBG), QC, at FL410. Joint Rescue Coordination Centre (JRCC) Trenton was notified.