Accident Details
Probable Cause and Findings
The nose landing gear’s failure to fully extend due to missing and damaged fastening hardware on the drive arm assembly.
Aircraft Information
Analysis
HISTORY OF FLIGHTOn March 14, 2015, about 1521 central daylight time, GoJet Airlines, dba United Express, flight 3645, a Bombardier CL-600-2C10, N157GJ, landed with the nose landing gear not extended on runway 32R at Chicago O'Hare International Airport (ORD), Chicago, Illinois. None of the 44 passengers and crew on board were injured, and the airplane sustained minor damage. The flight was operating under the provisions of Title 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from Gerald R. Ford International Airport (GRR), Grand Rapids, Michigan, to ORD.
On the previous day, the incident flight crew had flown the incident airplane to GRR and heard a sound when extending the landing gear on approach; all three landing gear extended normally. In a postincident interview, the captain described the sound as a "bang" that he thought was odd and that he had not heard before. The first officer indicated that, after landing, he inspected the nose gear, and it looked like the data plate had come loose on the strut. The captain stated that he sent photographs of the nose landing gear to company maintenance control personnel, who indicated that the problem appeared to be with the placard strap. The captain entered “placard strap bent” in the airplane logbook; he stated that he did not write up the “bang” sound but based his logbook entry on his conversation with maintenance control. Maintenance was performed on the airplane overnight to repair the damaged placard.
The next day, another crew flew the incident airplane on two legs, from GRR to Denver and back to GRR. The first officer of the other crew stated that they heard a "slight noise" when extending the gear for landing, which that captain described as a “little click,” and stated that this information was relayed to the incident captain.
For the incident flight, the captain was the pilot flying and the first officer was the pilot monitoring. The flight departed GRR about 1413, and during landing gear retraction, the crew heard a noise that the first officer later described as a "good clunk." They discussed the noise but continued the flight to ORD.
About 1438, during approach to runway 27L at ORD, the first officer selected the landing gear down, and the crew observed a GEAR DISAGREE caution message on the engine indicating and crew alerting system (EICAS). About 1439, the first officer cycled the landing gear handle up and back down, and they again observed a GEAR DISAGREE message on the EICAS along with a red nose gear position indicator. The crew conducted a go-around and received radar vectors from air traffic control (ATC) out of the airport traffic area to troubleshoot the problem.
About 1442, the first officer started to perform the GEAR DISAGREE checklist contained in the Quick Reference Handbook (QRH). In following steps in the checklist, the first officer cycled the landing gear handle up and then down again. According to the cockpit voice recorder (CVR), at 1444:21, the first officer stated that a note in the checklist said "not to do it more than once." The GEAR DISAGREE message persisted, and, at 1445:14, the CVR recorded a click as the first officer pulled the landing gear manual release handle.
The landing gear manual release handle activation attempt was unsuccessful, and the first officer continued to read the checklist, stating the next step was to accomplish the Landing Gear Up/Unsafe Landing procedure. Instead, the first officer performed the LDG GEAR Lever Jammed in the UP Position checklist, which was located at the top of page 13-5. He completed that checklist and read the last step that again directed them to accomplish the Landing Gear Up/Unsafe Landing procedure, which was located at the bottom of page 13-5. At 1447:14, the first officer stated "…and that's what we're doing…," followed by "…and that's-that, we're done.”
The flight crew discussed the fuel remaining and decided to conduct a low approach to have ATC tower personnel visually observe the landing gear position. At 1448:21, the crew declared an emergency with ATC, and shortly after, the captain briefed the cabin crew and passengers. The crew conducted the low approach, and, at 1459:13, an ORD ATC tower controller advised them that the nosewheel was “…definitely not down. or appears not down.” After the low approach, the crew discussed landing and evacuation procedures, briefed the passengers, and then discussed evacuation procedures with the cabin crew.
At 1512:52, ATC cleared the flight for the instrument landing system runway 32R approach. The crew configured the airplane for landing with flaps 45, and, at 1517:30, the ORD ATC tower cleared the flight to land on runway 32R.
At 1519:06, the first officer announced "brace, brace, brace" over the public address (PA) system. At 1520:32, the main landing gear touched down on the runway, and, at 1520:50, the CVR recorded the sound of scraping as the forward end of the fuselage contacted the runway. After the airplane came to a stop on the runway, the flight crew advised the cabin crew "…do not evacuate" and announced over the PA, "…no evacuation."
The flight crew shut down the engines and electrical power, and the passengers and crew remained on the airplane until ground transportation was available to transport them to the gate. The passengers then exited through the main forward cabin doors.
DAMAGE TO AIRPLANE
Postincident examination of the airplane revealed minor damage to the nose landing gear doors, and a bolt and bracket on the drag brace were found broken. The nose gear strut was not damaged and remained inside the nose gear well, with no evidence that it had dragged on the ground.
PERSONNEL INFORMATIONThe captain was hired by GoJet Airlines in February 2011 as a first officer and was upgraded to captain in 2013. The captain reported 5,222 hours total time, including about 1,146 hours as pilot-in-command and 3,734 hours total time on the CL-65; 892 of which was as pilot-in-command. The captain had type ratings for BE-1900 and CL-65 airplanes. There were no records or reports of previous aviation incidents or accidents involving the captain.
The first officer was hired by GoJet Airlines in October 2013. He reported 14,106 hours total flight time and 894 hours second-in-command time in the CL-65He held type ratings for LR-Jet, DA-10, and CL-65 airplanes. There were no records or reports of previous aviation incidents or accidents involving the first officer.
The captain and first officer had not flown together before this trip, and the incident occurred on the first leg of the second day of the trip.
AIRCRAFT INFORMATIONThe incident airplane’s nose landing gear was a double wheel, forward retracting type with two spin down assemblies. The nose landing gear consisted of a twin wheel shock strut and a folding drag brace that incorporated a mechanical downlock/uplock.
In normal operation, the nose landing gear drag brace assembly folded and positioned the shock strut relative to the nose of the fuselage in both extend and retract positions. It consisted of an upper drag brace, lower drag brace, over center lock link assembly (jury strut), and two tension springs. The upper drag brace assembly connected the lower drag brace assembly and the jury strut assembly to the airframe attachment point. The lower drag brace assembly connected the upper drag brace and the jury strut assembly to a lug integral to the forward side of the outer cylinder.
The jury strut assembly, comprised of lower and upper lock link assemblies, connected the upper and lower drag brace assemblies to the airplane attachment point, over center springs, and the lock actuator. Dual acting springs assisted the lock link assembly arms and were designed to ensure over center and mechanical locking of the jury strut.
The nose landing gear doors were driven by the nose landing gear and were open when the nose landing gear was down and closed when the gear was up. The nose landing gear doors opened and closed with landing gear motion through mechanical means. The forward door mechanism assembly was comprised of two door rods, a driven link assembly, upper and lower locks link assemblies, a drive link assembly, and a drive arm assembly. The door rods, each with rod ends and spherical bearings at each end, attached to lugs integral to their respective door assembly. Both door rods then connected to lugs integral to the driven link assembly, which had a clevis at the opposite end for pinning to a lug integral to gear bay structure.
The driven link assembly was acted upon by an upper link assembly, which connected to a lower link assembly. The lower link assembly was pinned to the upper drag brace and acted upon by the drive link assembly. The drive link assembly was pinned to the drive arm assembly, which was rigidly attached to the lower lock link of the jury strut.
When nose landing gear extension would begin, hydraulic pressure would be directed to the lock actuators, which would break the over center lock of the lock link assembly. The nose landing gear would be brought down and locked in the extended position by the retract actuator and two tension springs. The lock actuator and the tension springs completed a solid over center lock of the lock link assembly. To retract the nose landing gear, the hydraulic pressure would be directed to the lock actuator to break the downlock and to the retract actuator to raise the nose landing gear. The nose landing gear would retract into the wheel well and be locked into position by the two tension springs.
Maintenance
At the time of the accident, the GoJet Airlines CRJ 700 maintenance program was controlled by its Continuous Airworthiness Maintenance Program document, revision 41, dated December 19, 2014. The maintenance program consisted of line checks, work packages, and block checks, progressing from lighter to heavier maintenance requirements. The investigation revealed that all ...
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# DCA15IA089