N877GA

HISTORY OF FLIGHT

On March 29, 2007, about 1616 eastern daylight time, a McDonnell Douglas DC-9-83 (MD-83), N877GA, registered to Boeing Aircraft Holding Company and operated by Allegiant Air as flight 758, a 14 Code of Federal Regulations (CFR) Part 121 scheduled domestic passenger flight from Portsmouth, New Hampshire to Sanford, Florida, landed with the nose landing gear (NLG) retracted at the Orlando Sanford International Airport (SFB), Sanford, Florida. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed. The airplane received substantial damage. The airline transport-rated captain, airline transport-rated first officer (FO), 3 flight attendants (FA), and 151 passengers reported no injuries. One passenger received minor injuries and was taken to a local area hospital for observation and released. The flight originated from Portsmouth, New Hampshire, on March 29, 2007, at 1255.

The flight crew (FC) stated they were in cruise flight when a master caution light illuminated indicating a loss of the right hydraulic system pressure and hydraulic fluid. The FC used the checklist to trouble shoot the system. When the flight was about 10 miles from SFB the FC attempted to manually extend the main and nose landing gear (NLG) using the alternate extension control lever. Both main gear extended and locked into place; however the NLG did not extend. The FC communicated with the maintenance facilities in SFB and the airline's main base in Las Vegas, Nevada, for assistance in lowering the NLG, which was unsuccessful. The FC flew the airplane near the SFB control tower. The controller informed the FC that the NLG was in the retracted position and they could see fluid streaming from the aircraft. The FC continued to trouble shoot the system, and advised the passengers of the situation. The NLG would not extend after several attempts to lower the landing gear utilizing the alternate landing gear extension procedure. The captain declared an emergency, briefed the passengers, and landed on runway 9 with the NLG in the retracted position.

PERSONNEL INFORMATION

The captain, age 47, holds an airline transport pilot certificate with ratings for airplane multiengine land. He also holds a commercial pilot certificate with ratings for airplane single-engine land, and airplane instrument, which was issued on September 13, 2006. The captain holds a flight instructor certificate with ratings for airplane single-engine, airplane multiengine, and instrument airplane which was issued on December 19, 1994. The operator hired the captain on September 29, 2005, and he completed initial indoctrination training on October 7, 2005. Initial simulator qualification for the MD-80 was completed on November 22, 2005, and his initial operations check (IOE) was completed on December 11, 2005. He completed ground school for upgrade to captain in the MD-80 on September 6, 2006. Simulator training for the upgrade was completed on September 13, 2006, and his initial IOE/flight review, and line check as a captain was completed on October 30, 2006. His last simulator check before the accident was on March 7, 2007. He is type rated in the DC-9 and Lear jet. The captain has 7,145 total flight hours of which 2,996 hours are in the MD-80, and 105 hours as pilot-in-command. He holds a first-class medical certificate issued on May 22, 2007, without limitations or waivers. Review of the captain's training records revealed all pertinent aviation records pertaining to 14 CFR Part 121 airman competency and proficiency checks had been recorded as conducted.

The first officer (FO), age 37, holds an airline transport pilot certificate with ratings for airplane multiengine land. He also holds a commercial pilot certificate with ratings for airplane single engine land, and airplane instrument which was issued on January 29, 2005. In addition, the FO holds a flight instructor certificate with ratings for airplane single-engine, airplane multiengine, and airplane instrument which was issued on March 21, 1999. The operator hired the FO on September 28, 2006. He completed initial indoctrination training and ground school for the MD-80 on October 26, 2006. Simulator training for qualification in the MD-80 was completed on November 7, 2006. He completed his initial IOE/ flight review on November 20, 2006 and was qualified as a FO on the MD-80. No additional simulator training or line checks were preformed before the accident. The FO is type rated in the Boeing 737, ATR-42 and ATR-72. The FO has 5,300 total flight hours of which 300 hours are in the MD-80. The FO holds a first-class medical certificate issued on March 14, 2007, without limitations or waivers. Review of the FO training records revealed all pertinent aviation records pertaining to 14 CFR Part 121 airman competency and proficiency checks had been recorded as conducted.

A review of records provided by the operator revealed that the No.1 FA was hired on October 1, 2005. The FA completed initial flight attendant training on October 6, 2005, and her last recurrent training on the MD-80 was on October 18, 2006. The No.2 FA was hired on October 26, 2006. The FA completed initial flight attendant training on October 31, 2006. The No.3 FA was hired on October 1, 2005. The FA completed initial flight attendant training on October 10, 2005, and his last recurrent training on the MD-80 was on September 21, 2006.

AIRCRAFT INFORMATION

The DC-9-83 (MD-83), serial number 53467 is a twin-engine, medium range, single isle commercial jet airplane with a tricycle landing gear. McDonald Douglas manufactured the airplane in 1994. The airplane has a seating capacity of 3 flight crew, 4 flight attendants, and 150 passengers. The airplane has two rear fuselage-mounted Pratt and Whitney JT8D-219, 21,700 pounds of thrust turbo fan engines, small, highly efficient wings, and a T-tail. The airplane is in a continuous airworthiness program and the last A check was completed on March 20, 2007. The total airframe time at the time of the A check was 22, 138.8 hours. The left engine had 26309.3 total flight hours at the time of the accident, and had flown 70.8 hours since the last A check. The last engine shop visit was on December 6, 2005. The right engine had 20, 982 total flight hours at the time of the accident, and had flown 70.8 hours since the last A check. The last engine shop visit was on November 30, 2005. The last gear retraction test before the accident and emergency gear extension test was completed on April 26, 2004.

METEOROLOGICAL INFORMATION

The 1628 SFB surface weather observation was: wind 070 degrees at 16 knots gusting to 21 knots, visibility 10 miles, few clouds at 4,500 feet, temperature 27 degrees Celsius, dew point temperature 13 degrees Celsius, and altimeter 30.14 inches of mercury.

FLIGHT RECORDERS

The Fairchild Model A-100 cockpit voice recorder (CVR) was forwarded to the National Transportation Safety Board Vehicle Recorder Division for analysis. The CVR did not sustain any heat or structural damage and audio information was successfully extracted. The recording consisted of three channels of audio information containing captain and copilot hot microphones, interphone audio, and one channel containing cockpit area microphone audio. The accident events were captured on the recording, the audio offered no additional information that had not been obtained through other sources during the investigation. A CVR group was not formed and a transcript was not prepared.

The Honeywell model 980-47, 64-word solid-state flight data recorder (SSFDR) was forwarded to the Safety Board for analysis. The recorder was in good condition and data was successfully extracted. The data indicates that approximately 51.1 minutes after take off, the right hydraulic low status transitioned from "Not Low" to "Low," and 3 minutes 21 seconds later, the left hydraulic low status also transitioned from "Not low" to "Low." One second later, the left hydraulic status transitioned back to "Not Low," but the right hydraulic low status remained at "Low" for the rest of the recording. Approximately 19.7 minutes after the left hydraulic low status had transitioned back to "Not Low," it transitioned to "Low" again and remained at "Low" for 8 seconds before it transitioned back to "Not Low," and remained at "Not Low" for the remainder of the recording. About 2.1 hours after the last time the left hydraulic low status had transitioned back to "Not Low," the weight on wheels for the left and right main landing gear both indicated ground. The SSFDR data ended about 1.2 minutes later.

WRECKAGE AND IMPACT INFORMATION

The airplane came to a stop on runway 09 in a nose down attitude, and an emergency evacuation was completed. Examination of the airplane revealed structural damage at the 110 bulkhead extending aft to station 228, and between longerons 24L to 24 R. Initial inspection of the airplane by Federal Aviation Administration (FAA) inspectors revealed that a B-nut to the check valve on the rudder power hydraulic shut off valve (P/N 3772374-5503), was separated from the valve, resulting in a total loss of right hydraulic quantity and pressure. The hydraulic tube, P/N 7912641-969, including the B-nut and check valve, P/N 2C6540, were sent to the Safety Board Materials Laboratory in Washington, D.C. for analysis. The Safety Board metallurgist did not observe any abnormalities with the B-nut threads or the mating check valve threads.

Examination of the cockpit by the FAA inspectors revealed the landing gear handle was in the stowed position. A placard on the alternate landing gear extension lever states, "Pull up forcibly Full Stroke." The airplane was placed on jacks and maintenance personnel in the presence of the FAA inspectors extended the nose landing gear. Further examination of the airplane revealed no anomalies with the nose water spray installation, nose wheel lockout system, nose strut serv...