Reasons for a Tail Scrape
Thread Starter
Joined: Mar 2006
Posts: 1,115
Likes: 86
From: England
Reasons for a Tail Scrape
A recent AAIB investigation reported a minor tail scrape during landing.
The Operator’s Flight Operations Manual provided advice to crews on possible reasons for a scrape – The most common cause of a tail strike on landing is a fast approach. This leads to a prolonged time in the flare, followed by a rapidly increasing ground closure rate.
This appears to be unusual advice as higher speeds are normally associated with lower body angles, from which it is assumed there is more tail clearance during (a long) landing. If a high RoD were to be the cause then much greater damage can be expected; this was not the case.
Can any ARJ operators elaborate on the reasons / advice about speed?
There is also an inconsistency in the report which concludes A high rate of descent developed which the commander attempted to reduce by increasing the flare which caused the aircraft fuselage to exceed the body contact angle of 6.9º causing minor damage to the tail strike protection plate. However the manufacturer states that a scrape is only likely at pitch angles above 8 deg with a descent of 10ft/sec.
Although the incident landing was ‘firm’ (high FDR ‘g’ levels do not equate to a heavy landing) the pitch angle was only 7 deg at a calculated 8 ft/sec (480 ft/min – and my interpretation of the FDR only gives 6 ft/sec), thus based on this geometry and dynamics, a scrape was unlikely.
Any ARJ operators with a view?
The Operator’s Flight Operations Manual provided advice to crews on possible reasons for a scrape – The most common cause of a tail strike on landing is a fast approach. This leads to a prolonged time in the flare, followed by a rapidly increasing ground closure rate.
This appears to be unusual advice as higher speeds are normally associated with lower body angles, from which it is assumed there is more tail clearance during (a long) landing. If a high RoD were to be the cause then much greater damage can be expected; this was not the case.
Can any ARJ operators elaborate on the reasons / advice about speed?
There is also an inconsistency in the report which concludes A high rate of descent developed which the commander attempted to reduce by increasing the flare which caused the aircraft fuselage to exceed the body contact angle of 6.9º causing minor damage to the tail strike protection plate. However the manufacturer states that a scrape is only likely at pitch angles above 8 deg with a descent of 10ft/sec.
Although the incident landing was ‘firm’ (high FDR ‘g’ levels do not equate to a heavy landing) the pitch angle was only 7 deg at a calculated 8 ft/sec (480 ft/min – and my interpretation of the FDR only gives 6 ft/sec), thus based on this geometry and dynamics, a scrape was unlikely.
Any ARJ operators with a view?
PPRuNe supporter
Joined: Dec 2003
Posts: 1,676
Likes: 0
From: Planet Earth
I think most tail strikes in general are incurred during landing after an unstabilized approach (too fast). Your AFM should have information that tells you the struts compressed angle which will be a lower number.
Guest
Posts: n/a
Coming over the pianno keys too fast, (say 5-10 kts fast) is no real problem if you accept that you must aim for a positive touchdown not a softly milked flare. Speed contol depends on whether you are going into known winshear or gusty surface winds, when a lot of folk add a couple of kts for granny. Some types are notoriusly unresponsive around Vref, so +5kts can give more control in roll.
I've flown with a number of "sold sweats" who regularly fly 5kts fast and drive it on, and others who get the speed just right and milk it. Funny how it's the +5kts brigade that make the more consistant better landings.....
Then again, the 146 is perhaps not the best example, as it's one of natures more forgiving beasts in the landing phase.....
I've flown with a number of "sold sweats" who regularly fly 5kts fast and drive it on, and others who get the speed just right and milk it. Funny how it's the +5kts brigade that make the more consistant better landings.....
Then again, the 146 is perhaps not the best example, as it's one of natures more forgiving beasts in the landing phase.....
