Sunstate DH8D at Brisbane on Nov 5th 2013, tail scrape on landing

Last Update: October 28, 2016 / 15:23:01 GMT/Zulu time

Bookmark this article

Photo of Sunstate Airlines VH-QOT, De Havilland Dash 8 (400) — Sunstate Airlines VH-QOT, De Havilland Dash 8 (400) (Photo credit: Aero Icarus / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Nov 5, 2013

Classification
Incident

Airline
Sunstate Airlines

Flight number
QF-2545

Departure
Roma, Australia

Destination
Brisbane, Australia

Aircraft Registration
VH-QOT

Aircraft Type
De Havilland Dash 8 (400)

ICAO Type Designator
DH8D

Airport
Brisbane International Airport, Brisbane

Airport ICAO Code
YBBN

A Sunstate de Havilland Dash 8-400 on behalf of Qantas, registration VH-QOT performing flight QF-2545 from Roma,QL to Brisbane,QL (Australia), landed on Brisbane's runway 19 at about 14:30L (04:30Z), however, the tail of the aircraft contacted the runway surface during roll out. The aircraft rolled out without further incident and taxied to the apron, where passengers disembarked normally.

Qantas reported a Qantaslink Dash 8-400 contacted the runway surface with its tail while landing in Brisbane at about 14:30L arriving from Roma. The aircraft received minor damage, it was a tail scrape not a tail strike, and passengers most likely did not notice the tail contact at all. The aircraft is being inspected.

Three Qantaslink flights from Roma landed at Brisbane at about 14:30L: QF-2545 landed at 14:24L, QF-2771 (VH-QOF) at 14:26L and QF-2781 (registration VH-QOM) at 14:44L, however VH-QOM appeared on radar on its next flight, while VH-QOT and VH-QOF show no subsequent flights so far.

On Nov 8th 2013 the ATSB reported the aircraft involved was VH-QOT. After landing the crew noticed a "touched runway" light and advised air traffic control of a possible tail strike. A runway inspection confirmed a tail contact with the runway. An examination of the aircraft found abrasions to the underside of the belly with neglibible damage to the underlying sections. The ATSB annotated while there have been many tail strikes of DH8Ds around the planet partly with substantial damage, this was the first encounter in Australia.

On Oct 28th 2016 the ATSB released their final report concluding the probable cause of the incident was:

Contributing factors

- In the last 50 ft of both approaches to land, the first officer, who was the pilot flying, did not manage engine power commensurate with the aircraft's declining energy state, inducing the first officer to inadvertently pitch up to control the descent rate and exceed the pitch angle limits.

- Varied emphasis on the appropriate handling technique and pitch attitude awareness during first officer training did not assure consistent application of an appropriate landing technique in the Dash 8-400 aircraft.

Other findings

- The use of Flap 15 for landing results in a margin of 1.9° between the nominal landing flare angle and the tail strike angle, compared to a margin of 3.9° when using Flap 35 and a typical margin for other transport aircraft of over 5°.

- About 5 months prior to these occurrences, QantasLink identified an emerging trend in high pitch attitude occurrences during landing. In response, a focused flight operations analysis was commenced, and was ongoing, at the time of these occurrences.

The ATSB reported that a similiar occurrence, same root case, happened on Dec 11th 2013 at Brisbane involving the Dash 8-400 registration VH-QOS. Both occurrences are covered by this final report.

The ATSB reported that both first officers were trainees supervised by a training captain flying the aircraft. Both landings were conducted using flaps 15 and a propeller rpm of 1,020 rpm. Both approaches were fully stabilized until about 50 feet AGL.

VH-QOT settled on the runway smoothly in gusting winds at 122 KIAS (Vapp 127 KIAS, Vref 119 KIAS) and engine torque 10% (expected torque 17%) but bounced and became airborne again for about 4 seconds, during the bounce the pitch angle increased to 7.5 degrees nose up while the airspeed dropped to 116 KIAS, upon second touchdown the "TOUCHED RUNWAY" indication illuminated. A runway inspection revealed debris on the runway consistent with a tail strike.

VH-QOS was descending through 100 feet AGL at 127 KIAS (Vapp 120 KIAS, Vr 113 KIAS), when the first officer initiated flare, at 30 feet the captain noticed decreasing speed dropping through 115 KIAS and advised to increase power. Before the first officer, surprised by the call, comprehended the purpose, he reduced engine power to idle at 10 feet AGL and the aircraft touched down at 100 KIAS with a pitch attitude of 8.4 degrees nose up.

The ATSB reported the landing attitude on the Dash 8-400 and -300 should not exceed 6 degrees nose up, instead engine power should be used to arrest the descent.

The ATSB analysed: "Due to its design and length, the Dash 8-400 has an increased risk of tail strike on landing that must be managed by the flight crew. The tail strikes that occurred on 5 November and 11 December 2013 took place when the affected aircraft were being flown by flight crew members under training. Both tail strikes were characterised by insufficient application of engine power and overpitching during the landing flare."

The ATSB continued analysis:

The purpose of the flare is to reduce the rate of descent prior to touchdown. In the Dash 8-400, which has a relatively low tail strike attitude, the flare needs to be effected by careful use of pitch attitude change and engine power management.

In general terms, increasing the pitch attitude increases the lift generated by the wings and will therefore reduce the rate of descent. Due to the design of the Dash 8, the rate of descent can also be reduced by increasing engine power. Any increase in engine power will increase the airflow over the wing and produce additional lift. Conversely, reducing power to flight idle too early can result in a loss of lift and a significant increase in propeller drag, particularly when 1,020 RPM is used.

While not necessarily intuitive, a high sink rate during the flare must not be corrected in the Dash 8-400 by pitching up beyond 6°, as this could result in a tail strike. The correct response is to increase power or, if necessary, conduct a go around.

The ATSB concluded analysis:

The selection of flight idle during the landing flare, possibly aggravated by the increased drag associated with a propeller setting of 1,020 RPM, resulted in a significant loss of performance that was incorrectly countered by the respective FO by increasing the aircraft’s pitch attitude.

In both cases, the FO did not manage the engine power commensurate with the aircraft's declining energy state, inducing them to inadvertently pitch up to control the descent rate and exceed the aircraft’s pitch angle limit.

With respect to the selection of flaps the ATSB analysed:

Most air transport aircraft use flap settings of about 30° or greater for landing. Those settings provide for tail strike margins in excess of 5°. Despite the operational benefits of using Flap 35, full flap on the Dash 8-400, flight crew appear to prefer the use Flap 15 due to the aircraft being more responsive, easier to handle and easier to land. While the use of Flap 15 does provide a performance benefit in the event of a go-around, none of the airports to which QantasLink operated required its use.

While flight crews may prefer the use of Flap 15 for landing, the margin between a normal approach attitude and tail strike attitude in that configuration is reduced from about 4° to about 2°.

Metars:
YBBN 050600Z 11012KT 9999 FEW030 21/13 Q1021 NOSIG
YBBN 050530Z 11012KT 9999 FEW030 22/12 Q1021
YBBN 050500Z 11014KT 9999 FEW035 22/14 Q1021 NOSIG
YBBN 050430Z 12013KT 9999 SCT030 22/13 Q1021
YBBN 050400Z 10013KT 9999 FEW030 SCT063 23/12 Q1022 FM0400 11015KT 9999 SCT035
YBBN 050330Z 11011KT 9999 FEW030 BKN062 22/12 Q1022
YBBN 050300Z 11012KT 9999 FEW030 BKN055 23/12 Q1022 FM0300 11015KT 9999 SCT035
YBBN 050230Z 11012KT 9999 FEW030 BKN062 23/11 Q1022
YBBN 050200Z 11012KT 9999 FEW030 BKN055 21/11 Q1023 FM0200 11015KT 9999 SCT035
YBBN 050130Z 11011KT 9999 SCT035 24/11 Q1023
YBBN 050100Z 10012KT 9999 FEW032 SCT042 22/10 Q1023 FM0100 11015KT 9999 SCT035