Tailstrikes

Contents

Some facts, tips and news about tailstrikes on the 737.

Tailstrike Geometry

Takeoff Risk Factors

Landing Risk Factors

List of tailstrike events

The summary is that most tailstrikes occur on landing and most landing tailstrikes follow an unstabilised approach. Furthermore, the -4/800 tailskid does not protect the aircraft for landing.

All of the information, photographs & schematics from this website and much more is now available in a 374 page printed book or in electronic format.

*** Updated 05 Aug 2023 ***

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A 737-900 tailstrike after a bounced landing. Notice the contact of the extended tailskid, a feature only installed on the -800SFP and -900ER

Tailstrike Geometry (Ref FCTM)

For Classics, Flaps 1 (-300) and flaps 5 (-400) takeoffs have the least clearance. Consider using a larger flap setting for takeoffs at light gross weights. Because of the short fuselage, aft fuselage contact is unlikely in the 737-500.

For NGs, Flaps 1 and 5 (-800/900/900ER) takeoffs have the least clearance. Consider using a larger flap setting for takeoffs at light gross weights. Because of the short fuselage, aft fuselage contact is unlikely in the 737-600.

Data taken from a presentation by Boeing given in 2004

• More tail strikes occur on landing than on takeoff
• 82% of 737-400 tail strikes occurred on landings
• 737-400 does not have tail skid protection for landing therefore has higher damage
• 70% of 737-800 tail strikes occurred on landings
• 737-800/900 tail skid does not protect the aircraft body for landing. However, 737-800/900 have adequate aft body landing clearance
• 1994-1995 was another tail strike peak period with all Boeing models due to increased deliveries and/or new pilots

The 737-800 tailskid

Re the 737-800

• 13 total tailstrikes to date (2004)
  • 3 without damage (not listed)
  • 10 with damage
  • 3 occurred during takeoff
  • 7 occurred during landing
  • limited damage occurred during takeoff tailstrikes
  • the 737-800/900 tailskid protects the aircraft on takeoff not on landing

The 737-800SFP and -900ER tailskid extends 5 inches to help protect against landing tailstrikes

The FCOM has recently added the following warning:

"CAUTION: Cartridge assembly warning placard must be checked as soon as possible after the tailstrike. The tail skid skirt faring may re-extend due to gravity as time passes resulting in a reading error on the warning placard decal."

This photo from a 737-800 tailstrike following a bounced landing shows how far from the tailskid the fuselage contact will occur if the tailstrike is on landing.

A 737-400 tailstrike on takeoff at Cork, Jun 2016

Takeoff Risk Factors

Mis-trimmed stabilizer

• Usually results from using erroneous data
– Wrong weights
– Incorrect center of gravity (CG)
• Nose up mis-trim can present problems
– Normal recommended rotation rate is 2 to 3 dps
– Nose up mis-trim can rotate 5 dps or more
– Aircraft may try to fly off runway without any pilot input

An example of incorrect CofG was a Flybondi 737-800 LV-HQY RTO after tailstrike at Iguazu on 16 Jul 2018. The preliminary report showed that the although the loadsheet showed 22.2% MAC, many of the passengers sat towards the rear of the cabin resulting in a T/O CoG around 40% MAC. The aircraft pitched up shortly after T/O thrust was applied, the fuselage contacted the runway and an RTO was performed.

Note that incorrect take-off speeds due to data entry errors have been the cause of several 737 tailstrikes. A good report on a recent event was recently published by the Australian ATSB here.

Also Blue B738 at Birmingham on Jul 28th 2018, tail scrape on departure

Synopsis:

Prior to departure the aircraft’s takeoff data was calculated on an electronic flight bag (EFB) using its zero fuel weight (ZFW) instead of its takeoff weight (TOW). The pilots did not crosscheck or independently calculate the data. During the takeoff the aircraft suffered a tailstrike. Despite ATC asking the pilots if they had a tailstrike, the error subsequently being noticed in the EFB and a member of the cabin crew hearing a strange noise during the take off, the tailstrike checklist was not actioned. The aircraft continued to its destination and, after landing, damage was discovered on the underside of the aircraft.

Improper rotation techniques

• Too early or too late rotation
• Too fast or too slow rotation
• Excessive rotation rate
• Excessive initial pitch attitude
• Rotation at incorrect Vr for the weight and flap setting

Effects of Improper Rotation

• Slow or late rotation uses additional runway - lower height at runway end
• Early, over or fast rotation - decreases initial climb performance
• Early and/or fast rotation increases chance of tail strike

Improper use of the flight director

• Cannot rotate on the flight director
• Flight directors are designed to provide pitch guidance only after the aircraft is airborne, nominally passing 35 feet
• Proper rotation rate reaches 35 feet with about 15 degrees and a speed of V2 + 10 (V2 + 15 on some models)
• An aggressive rotation into the pitch bar may rotate the tail into the ground

Review of Proper Takeoff Techniques

• Use normal takeoff rotation technique. Use same technique for -600 thru -900
• Do not rotate early
• Do not rotate at an excessive rate or to an excessive attitude
• Ensure takeoff V speeds are correct and adjusted for actual thrust used
• Consider use of greater flap setting to provide additional tail clearance
• Consider using Full Thrust during gusty/crosswind conditions

Rotation prior to Vr

Excessive initial pitch attitude

Heavy derate/flight control abuse during gusty/crosswind conditions

A 737-400 tailstrike on landing at Moscow, Domodedovo, 23 Jul 2009

Landing Risk Factors

• Unstabilized approach
• Holding airplane off the runway in the flare
• Mis-handling of crosswinds
• Over-rotation during go-around

Note: Tail strikes on landing generally cause more damage. The tail may strike the runway before the main gear damaging the aft pressure bulkhead.

Unstablized Approach

• • Usually appears in every landing tail strike
  • Flight recorders show if not stabilized by 500 feet, will never get the approach stabilized
  – Excessive or insufficient airspeed in the flare
  – Long on runway touch down
  • Increases tendency towards large pitch and power changes in the flare
  • Spoilers add nose up pitching force when deployed Increases tendency toward vigorous nose up pull at touch down causing a tail strike
  • If the airplane is slow, pulling the nose up in the flare does not reduce the sink rate, but may increase it
  • Throttles above idle at touchdown add to instability.

Bounced Landings

The FCTM states:

"‘Bounced landings can occur because higher than idle power is maintained through initial touchdown, disabling the automatic speedbrake even when the speedbrakes are armed. During the resultant bounce, if the thrust levers are then retarded to idle, automatic speedbrake deployment can occur resulting in a loss of lift and nose up pitching moment which can result in a tail strike or hard landing on subsequent touchdown’"

A recent accident report by the AAIB analyses a 737-800 tailstrike following a bounced landing.

A recent report by the DGCA into a 737-800 tailstrike after a bounced landing at Dhaka.

Holding Airplane Off Runway in the Flare

• Allowing airspeed to decrease below Vref prior to landing flare resulting in high pitch attitude
• Trimming the stabilizer nose up just prior to or during landing flair
• Holding the airplane off with increasing pitch attitude in an attempt to make an extremely smooth touchdown
• Touchdown with an increasing pitch attitude
• Failure to fly nose gear onto runway immediately after main gear touchdown

Mis-handling of Crosswinds

• Crosswind landings may increase the tail strike risk, especially in gusty conditions
• To stay on glide path at high ground speeds, descent rates of 700 to 900 feet are required
• Cross controlling prior to touch down, reduces lift, increases drag, and may increase rate of descent
• Combined effects of high closure rate, shifting winds plus turbulence, can increase tail strikes

Over Rotation During Go-around

• Go-arounds initiated during flare and after a bounced landing, can cause tail strikes (eg HL7725)
• If a touchdown far down the runway is likely, consider a go-around
• Safe companies support go-arounds

Damage to a 737-800, LV-FUA, after a tailstrike on go-around. Note that the damage is forward of the tailskid (Photo: Ignacio Vittori)

 

Review of Proper Landing Techniques

• Maintain an airspeed of Vref + 5 kt minimum to start of flare
• Airplane should be in trim at start of flare; do not trim in the flare or after touchdown
• Do not “hold the airplane off” in an attempt to make an excessively smooth landing
• Immediately after main landing gear touchdown, release back pressure on control wheel and fly the nose wheel onto the runway
– Do not allow pitch attitude to increase after touchdown
– Do not attempt to use aero braking - it does not work !

A 737-900ER, landing at PDX. The concensus is that this was not a tailstrike - but it was very close!

Summary

• More tail strikes occur on landing than on takeoff
• Tail strikes are costly but can be prevented with proper training
• Tail strike awareness and training should be continuous
• Simulators can help
• Stabilize the approach by 500 feet AGL

Damage to a 737-800 tailskid after a bounced landing

22 Jan 2017 - Final report issued into Jet Airways 737-800 VT-JTD tailstrike on landing at Dhaka

Numbers of tailstrikes by phase of flight:

List of tailstrike events from AvHerald:

Gol B738 at Joao Pessoa on Nov 29th 2023, tail strike on landing

Garuda B738 at Banjarmasin on Aug 7th 2023, tail strike on go around (Preliminary report)

Sunwing B738 at Belfast on Jun 15th 2023, tail scrape on departure

Singapore 737-800 at Kathmandu on 6 May 2022, tail strike on departure

Icelandair 737-9 MAX at Toronto on 4 Mar 2023, tail strike on baulked landing

TUI 737-800 at Manchester on Mar 9th 2022, tail strike on departure

Icelandair 737-9 Max at Keflavik on 26 Feb 2022, tail strike on take-off

Blue Air 737-800 at Naples on 6 May 2022, tail strike on landing

United B739 at Denver on Jun 9th 2019, tail strike on landing

GOL B738 at Rio de Janeiro on Aug 31st 2021, tail strike on departure

TUI Belgium B738 at Marrakesh on May 2nd 2018, tail strike on landing

Flybondi B738 at Iguazu on Jul 16th 2018, rejected takeoff after tail strike

Pobeda B738 at Gyoumri on Aug 19th 2019, tail scrape on go around

Korean 737-900 HL7725 737-900 at Kansai on 9 Apr 2018 tailstrike on go-around

United B738 at San Jose on Jul 11th 2019, tail scrape on departure

India Express B738 at Kozhikode on Jul 1st 2019, tail scrape on landing

S7 B738 at Krasnodar on Jun 15th 2019, tail strike on balked landing

Blue B738 at Birmingham on Jul 28th 2018, tail scrape on departure

United B739 at Denver on Jun 9th 2019, tail strike on landing

SAS B738 at Alesund on Jan 13th 2019, tail scrape on departure

t'way B738 at Seoul on Aug 7th 2016, tail strike on go-around

Flybondi B738 at Iguazu on Jul 15th 2018, tail strike on departure

THY B739 at Istanbul on Jun 13th 2018, tail strike indication on departure

Swift B738 at Heraklion on Jun 10th 2018, tail strike on landing

TUI Belgium B738 at Marrakesh on May 2nd 2018, tail strike on landing

Korean B739 at Osaka on Apr 9th 2018, tail strike on go around

Ryanair B738 at Alicante on Apr 8th 2018, tail scrape on departure

Ryanair B738 at Bucharest on Feb 9th 2018, suspected tail strike on departure

Virgin Australia B738 at Auckland on Jan 17th 2018, tail scrape on departure

Jet Airways B738 at Bangkok on Jan 20th 2018, tail scrape on departure

Sun Express B738 at Hamburg on Dec 23rd 2017, tail strike on departure

Jet Airways B738 at Kolkata on Jan 14th 2015, tail scrape on landing (final report)

American B738 at Dallas on Sep 29th 2017, tail strike on departure

China Eastern B738 at Wenzhou on Sep 4th 2017, tail strike on landing

Delta B739 at Atlanta on May 23rd 2017, tail strike on landing

THY B738 at Istanbul on Apr 2nd 2017, suspected tailstrike

Aerolineas B738 at Bariloche on Feb 13th 2017, tail strike on go-around

Ryanair B738 at Warsaw on Feb 7th 2017, tail scrape on departure

Jet2.com B738 at Funchal on Feb 17th 2014, tail strike on landing (final report)

Corendon Dutch B738 near Amsterdam on Jan 26th 2017, technical problem, suspected tailstrike on departure

Jet Airways B738 at Dhaka on Jan 22nd 2017, tail strike on landing (final report)

Safair B734 at Cape Town on Nov 26th 2015, suspected tail strike on departure

Ryanair B738 at London on Jul 29th 2014, tail strike on landing (final report)

Ryanair B738 at Alicante on Mar 27th 2013, tail scrape on departure (final report)

TAROM B733 at Bucharest on Apr 4th 2011, tail strike on departure

Transavia B738 at Amsterdam on Apr 29th 2013, suspected tailstrike on departure

Titan B733 at Chambery on Apr 14th 2012, tail strike on departure (final report)

Gol B738 at Porto Alegre on Nov 16th 2011, tail strike on landing

TUIFly B738 at Tenerife on Mar 27th 2011, RTO due to tailstrike on departure

Ryanair B738 at Dublin on Sep 11th 2008, tailstrike on departure

Pegasus B738 at Cologne on Dec 20th 2008, tailstrike on departure

Ryanair B738 at Dublin on Sep 11th 2008, tail strike on departure (final report)

Comair (SA) B732 at Cape Town on May 3rd 2008, tail strike on departure

Ryan Int B738 at Milwaukee on Mar 14th 2008, tailstrike on departure

Ryanair B738 at Stansted on Feb 18th 2008, tailstrike on departure