Colgan DH8D at Houston on Apr 7th 2012, nose gear up landing

Last Update: October 22, 2015 / 21:39:00 GMT/Zulu time

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Photo of Colgan Air N213WQ, De Havilland Dash 8 (400) — Colgan Air N213WQ, De Havilland Dash 8 (400) (Photo credit: col29071962 / Flickr / License: CC by-nd)

Incident Facts

Date of incident
Apr 7, 2012

Airline
Colgan Air

Flight number
9L-4915

Departure
Little Rock, United States

Destination
Houston Intercontinental, United States

Aircraft Registration
N213WQ

Aircraft Type
De Havilland Dash 8 (400)

ICAO Type Designator
DH8D

A Colgan de Havilland Dash 8-400 on behalf of United, registration N213WQ performing flight 9L-4915/UA-4915 from Little Rock,AR to Houston Intercontinental,TX (USA) with 31 passengers and 4 crew, was on approach to Houston at 8000 feet when the crew declared emergency reporting the nose gear was not down and requested a low approach. The aircraft overflew runway 09 at low height about 20 minutes later, on final approach the crew reported they heard the nose gear doors flapping around and asked tower to check for any damage. Tower confirmed the nose gear was not down, both main gear were down. The aircraft positioned for another approach to runway 09 and landed on main gear and nose. No injuries occurred.

On Apr 17th 2012 the NTSB reported the aircraft landed with the nose gear retracted. There were no injuries to the occupants of the aircraft, the aircraft sustained substantial damage. An investigation has been opened.

In 2015 the NTSB released their final report concluding the probable cause of the accident was:

the nose landing gear alternate release handle was not pulled with sufficient enough force or distance to release the uplocks and allow extension of the nose landing gear.

Contributing to the accident was the dissimilar pull force and pull length set on the flight simulator that was used for flight crew training of alternate landing gear extension procedures and the lack of information available to crew members advising of the dissimilar pull force.

The NTSB reported that the crew received an amber nose gear open advisory indication as well as a landing gear inoperative indication and noticed unusual airflow sounds. In cruise flight a thump was heard and the abnormal indications extinguished, the crew received indication that the nose gear had fully retracted and the nose gear doors were closed. In consultation with maintenance the crew performed the alternate gear extension procedure at the destination, both main gear indicated down and locked, however the nose gear indicated red, the crew decided to land the aircraft with the nose gear retracted.

The NTSB reported that post accident examination was able to successfully extend the nose gear employing the alternate extension procedure as well as under hydraulic pressure. No fault was found with the landing gear system.

The NTSB annotated that 72 lbs of force were needed to extend the nose gear in the alternate extension in those tests. The design requirements were to pull the handle with 90lbs and extend the handle by 11 inches. However, a test in a flight simulator revealed that the force to simulate the gear extension via alternate procedure was significantly lower as compared to the aircraft. The NTSB wrote: "There was no guidance contained in the alternate landing gear extension procedure specifying required pull forces when using the alternate extension handle. Subsequent to the accident, the manufacturer added details to the alternate landing gear extension procedure in the Airplane Flight Manual regarding the maximum pull forces that a pilot may experience when the alternate extension handle is pulled."