avoiding hard landings

Avoiding Hard Landings

Capt. Marc PARISISHead of Flight and Cabin Crew Training

Presented by:

April 2007 Avoiding Hard Landings - 15th Performance & Operations conference© A

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Content

Hard Landings definition, detection, classification



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Definition of Hard Landing : Pilot’s point of view

• Pilots judge subjectively and comparatively the landings as being:

Soft – Normal – Firm – Hard

• Subjectively = modified or affected by personal views, experience, or background

• Comparatively = In a relative manner; by comparison to something else

“Hard landing suspected”: when the pilot decide that a structural examination is necessary


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Hard Landing information : Maintenance’s side

• Maintenance uses objective data to classify the landingsRecorded vertical acceleration at aircraft CGRecorded vertical speed using Radio Altimeter data

• Limit values will depend of:aircraft types and standardsQuality of recorded parameters

VERT ACC(g)

VERT Speed

NormalLanding

HardLanding

SevereHard

Landing


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Load Report

LOAD REPORT <15>


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Classification of the landing by maintenance

After a suspected hard landing:

• Classification of the landing using the Load Report

Normal landing = no actions required

Hard landing confirmed = perform inspection

Severe Hard Landing confirmed = AOG contact Airbus

Load Report not available = perform inspection


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Hard Landing confirmed: Maintenance inspection

Inspection is divided in different phases

• Phase 1: general inspection for primary damage and indication of remote damage (mainly external)

If damage = perform further inspection (phase 2) and required maintenance actions.

If no damage = end of inspection

• No damage = Aircraft can temporarily return to serviceGrace period (e.g. 30 days or 100 - 200 cycles)Waiting for further elaborated analysis of the event by AirbusRequired structural strength is maintainedRisk is only stress corrosion (e.g. gear not achieving full life)


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Identification of Hard Landing

Pilot: Subjective judgmentMaintenance: Objective but incomplete data

Maintenance system only covers straightforward hard landing events

– Rebounds, drift landing, landing with roll and high derotation on nose landing gear are not addressed by the current logic

Pilot should provide additional information on landing conditions

– Cockpit instrument indications, aircraft weight, quantity of fuel in each tank– If the touchdown was on main gears or on main and nose gears, or fast

derotation of the nose gear. – If the landing was straight, drifting, unsymmetrical, bounced,– If the crew heard a noise possibly related to a structural failure


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Identification of Hard Landing: New problem

• The pilots’ perception judgment and reporting has proven to be effective

• However, the perception of the severity of the landing is not so obvious for:

Long aircraft

Flexible aircraft

Complex landing gear system


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Future: Hard Landing Detector

• Design of new automatic self-reliant system with specific sensors and adapted high synchronized sampling rate

• This future system shouldProvide a rapid and direct “Go” OR “No Go and inspect” decision

for all circumstances Indicate which part of the aircraft has been impacted and to

which level

• Medium term (during development of this self-reliant system)Use selected data from this system to enhance the pilots’

conventional evaluation and reporting of the landings (data should be provided in a suitable way to be used directly by the pilots)


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Today situation

• The primary source of identifying a suspected hard landing is the flight crew

• It is flight crew’s duty to detect and report a suspected hard landing

• Airbus recommends the active use of the Load Report15


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Content

Hard Landings definition, detection, classification



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Main sources of Hard Landings

• Hard landings usually result directly from:Non-stabilized approachesInappropriate approach speedDestabilization of the approach in the last 100 ftIncorrect flare techniquesIncorrect derotation techniques (nose landing gear)

• And subsequently from:Reluctance to perform a go-aroundDual sidestick inputsBounce at landing incorrect recovery techniques

Contributing conditions are:– Crosswind, Windshear or downburst– Limited runway


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Flying stabilized approaches

Rushed and non-stabilized approaches are one of the main sources of hard landings

• Refer to the Flight Operations Briefing Notes“Flying Stabilized Approaches”“Aircraft Energy Management during Approach”

• If the aircraft is not stabilized at:1000 feet in IMC, or500 feet in VMC, oras restricted by Operator policy/regulations,

a go-around must be initiated.


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Flying stabilized approaches


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Approach speed

• Determination of approach speedIn most cases, the FMGS provides valuable VAPP on MCDU

PERF APPR page once tower wind and landing configuration has been inserted

The flight crew can insert a higher VAPP in case of strong suspected downburst, or gusty crosswind greater than 20 knots but this increment is limited to 15 kt above VLS

• Managed speed should be usedManaged speed provides Ground Speed mini (GS mini)

guidance, even when the VAPP has been manually inserted“Ground Speed mini” function will keep the aircraft energy

level above a minimum value, whatever the wind variations or gusts.


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Destabilization of the approach in the last 100 ft

Common errors• Descending below the final path ("duck under")• Reducing the drift too early

• Autopilot disconnectionPilot should disconnect the AP early enough to resume

manual control of the aircraft and to evaluate the drift before flare.

• High sink rate avoidanceIn the very late stages of the approach, priority should be

given to attitude and sink rate. If normal touchdown distance is not possible perform a go-around


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Flare techniques

• Flare height varies with different parameters such as weight, rate of descent, wind variations, …

• Avoid under flaring.The rate of descent must be controlled prior to the initiation of

the flare (rate not increasing)Start the flare with positive backpressure on the sidestick and

holding as necessaryAvoid forward stick movement once flare initiated (releasing

back-pressure is acceptable)

• Retard thrust levers when best adapted


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Derotation techniques – Fly the nose down

• When the aircraft is on the ground, pitch and roll control operates in Direct Law.

Derotation is conventional

• Fly the nose down smoothly, but with no delay


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Reluctance to perform a go-around

• Go-around is possible at anytime until the selection of the reverse

• Even if a late go-around will not avoid the contact with the runway it should soften it and could avoid a hard touch

• Once the go-around has been initiated it must be completed

Reversing a go-around decision is hazardous– e.g. F/o initiating a late go-around; Captain overriding and trying

to land the aircraft


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Dual sidestick inputs

• The basic task sharing principle for any aircraft operation is that one pilot is PF at a time

If the PNF feels he must intervene, he should press the Priority P/B while calling “I have controls”

• “Instinctive” Dual Input: instinctive reactions on the sidestick by the PNF surprised by the development of a dynamic situation

• In prolonged “Dual Input” situation : both PF and PNF will be aware of the dual input situation by the light and aural indicators.

it is to the Captain to take over by pressing the Priority P/B while saying “I have controls”


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Bounce at landing


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Bounce at landing

Flight Operations Briefing Notes“Bounce Recovery - Rejected Landing”

Bounce at landingMaintain pitch attitude (freeze and control the pitch)Keep thrust idleDo not increase pitch (tail strike)Complete the landing

Strong bounce → Go AroundGo around maintaining pitch attitudeKeep flaps ; keep landing gearOnly when positive climb is properly established

–Flaps one step and Landing Gear up


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Crosswind landings


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Crosswind landings

Flight Operations Briefing Notes“Landing Techniques – Crosswind landings”

• Final approach with crosswind drift correction with wings level (crabbed-approach)

• During the flare, rudder should be applied as required to align the aircraft with the runway. Any tendency to drift downwind should be counteracted by an appropriate roll input on the sidestick

• In case of very strong crosswind, combination of the partial de-crab and wing down techniques may be required

Aircraft can be landed with a residual drift (max 5°) to prevent an excessive bank (max 5°)


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Windshear – Down burst: Apply FCOM procedures

• Delay landing, or divert to another airport, until conditions are more favorable

Select the most favorable runway, in conjunction with the most appropriate runway approach aid

Select Flaps 3Use managed speed in approach phase

• Recovery techniquesSet thrust levers to TOGA. If the autopilot is engaged, use it (be aware that automatic

disengagement may occur) Follow SRS orders.Do not change configurationClosely monitor the flight path and speed


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Avoiding Hard Landing – Airbus documentation

• Airbus Operational and Training documentationFCOM – FCTMFCOM Bulletin N°819 “Avoiding Hard Landings” for LR

• Additional documentationFlight Operations Briefing Notes

• An e-briefing for pilots dedicated to hard landing prevention is available:

Specific presentationsSpecific videosOperational and Training documentation references


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Conclusion

• It is pilot’s duty to detect and reporta suspected Hard Landing

• Hard landings usually result directly from:Non-stabilized approachesInappropriate approach speedDestabilization of the approach in the last 100 ftIncorrect flare techniquesIncorrect derotation techniques (nose landing gear)

• And subsequently from:Reluctance to perform a go-aroundDual sidestick inputsBounce at landing incorrect recovery techniques

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