Date:	Friday 19 September 2014
Time:	08:47
Type:	Embraer EMB-505 Phenom 300
Owner/operator:	NetJets
Registration:	N322QS
MSN:	50500165
Year of manufacture:	2013
Total airframe hrs:	597 hours
Engine model:	Pratt & Whitney Canada PW535E
Fatalities:	Fatalities: 0 / Occupants: 2
Aircraft damage:	Substantial, repaired
Category:	Accident
Location:	Conroe-Lone Star Executive Airport, TX (CXO) -   United States of America
Phase:	Landing
Nature:	Ferry/positioning
Departure airport:	Nashville International Airport, TN (BNA/KBNA)
Destination airport:	Conroe-Lone Star Executive Airport, TX (CXO/KCXO)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
An Embraer EMB-505 Phenom 300 corporate jet sustained substantial damage in a runway excursion accident at Conroe-Lone Star Executive Airport, Texas.
The positioning flight originated from Nashville International Airport, Tennessee, at 07:06 and was bound for Conroe-Lone Star Executive Airport, Texas.

Approach
The pilots planned to land on runway 14, which was assumed to be wet. Before the flight, notices to airmen (NOTAMs) had been issued, which stated that the runway 14 threshold had been displaced 3,377 ft and that the instrument landing system and RNAV instrument approaches were not available. Although the NOTAMs were included in the flight release paperwork, dispatch personnel overlooked them, which resulted in flight planning numbers predicated on the full length of runway 14.
During the approach, the pilots listened to the automatic terminal information service information and then became aware that runway 14 was shortened due to construction.
Subsequently, the pilots calculated the landing distance required to land on a wet runway and chose to land on runway 1, which was the longer runway. The PIC reported that, during the approach, they encountered light rain but that the rain was moving away from the airport, which alleviated any concern regarding standing water on the runway.

Landing
The SIC flew a stabilized approach 9 knots above the reference speed (Vref) and that the airplane touched down 903 ft from the runway threshold at a groundspeed of 118 knots. The SIC stated that he began braking with half pressure and continued to increase the brake pressure to maximum, which was the normal braking procedure, but that the airplane did not appear to be decelerating.
The PIC informed the SIC that they needed to slow down, and the SIC replied that he had "no braking." The SIC then applied the emergency parking brake (EPB), but the airplane still did not slow down. FDR data indicated that the airplane achieved its maximum deceleration during the landing roll before the application of the EPB. FDR data showed that, once the SIC applied the EPB, the wheel speed dropped to 0. After determining that there was insufficient runway remaining for a go-around, the pilots realized that the airplane was going to exit the end of the runway. Subsequently, the airplane began to skid along the runway, which resulted in reverted-rubber hydroplaning, thus decreasing the stopping performance, and then exited the departure end of the runway and continued about 400 ft in soft terrain before it impacted a ditch and came to a stop.
An examination of the brake system and data downloaded from the brake control unit indicated that the brake system functioned as commanded during the landing. Analysis of the runway surface and the amount of precipitation showed that there should have been no standing water on the runway. Landing distance calculations performed in accordance with the aircraft flight manual (AFM) showed that, even though the SIC exceeded Vref, the airplane should have been able to stop on the available runway.

Braking friction
According to the National Transportation Safety Board's airplane performance study, the maximum wheel braking friction coefficient achieved during the portion of the ground roll before the application of the EPB was significantly less than the maximum wheel braking coefficient that would have been expected given the unfactored wet-runway landing distances published in the AFM. However, the study determined that, if the EPB had not been engaged and airplane had maintained the braking friction level attained during the landing roll before the engagement of the EPB, it would have been able to stop on the available runway. Therefore, the SIC's application of the EPB, which locked the wheels, reduced the friction level, and decreased the braking performance, prevented the airplane from stopping on the available runway.
Nonetheless, the braking friction deficit observed in this accident showed that the stopping performance of the airplane was more consistent with AFM landing distances for runways contaminated with standing water than for runways that were merely "wet" even though it was determined that the runway could not have been flooded.
Since the accident, the operator has issued a flight operations bulletin instructing pilots to conduct a landing distance assessment using the AFM contaminated runway performance data for the lowest contamination depth when the following three conditions exist: 1) the runway did not have a treated surface, 2) thrust reversers were deferred or not installed, and 3) the airport was reporting rain or heavy rain.

PROBABLE CAUSE: "The second-in-command's (SIC) engagement of the emergency parking brake (EPB), which decreased the airplane's braking performance and prevented it from stopping on the available runway. Contributing to the SIC's decision to engage the EPB was the lower-than-anticipated deceleration due to a wet-runway friction level that was far lower than the levels used to determine the wet-runway stopping distances in the Airplane Flight Manual (AFM) and necessitated a landing distance considerably greater than that published in the AFM."

13:32 UTC / 08:32 local time:
KCXO 191332Z 00000KT 2SM RA BR SCT007 BKN024 OVC080 23/22 A2993 RMK AO2 P0017 T02280222

13:41 UTC / 08:41 local time:
KCXO 191341Z 00000KT 2SM +RA BR FEW005 BKN080 OVC100 23/22 A2993 RMK AO2 P0021 T02280222
Winds: calm; Visibility: 2 miles; heavy rain, mist; few clouds at 500 feet AGL; broken clouds at 8000 feet AGL; overcast cloud deck at 10000 feet AGL; Temperature: 23°C; Dewpoint: 22°C; pressure 1013.6 mb

13:53 UTC / 08:53 local time:
KCXO 191353Z 00000KT 2 1/2SM RA BR FEW004 BKN055 OVC090 23/22 A2994 RMK AO2 SLP134 P0025 T02280222
Winds: calm; Visibility: 2,5 miles; rain, mist; few clouds at 400 feet AGL; broken clouds at 5500 feet AGL; overcast cloud deck at 9000 feet AGL; Temperature: 23°C; Dewpoint: 22°C; pressure 1014 mb

13:59 UTC / 08:59 local time:
KCXO 191359Z 00000KT 3SM RA BR SCT004 BKN021 OVC090 23/22 A2994 RMK AO2 P0002 T02280222

NTSB
ABC

photo (c) NTSB; Conroe-Lone Star Executive Airport, TX (CXO); 19 September 2014; (publicdomain)

photo (c) NTSB; Conroe-Lone Star Executive Airport, TX (CXO); 19 September 2014; (publicdomain)

photo (c) NTSB; Conroe-Lone Star Executive Airport, TX (CXO); 19 September 2014; (publicdomain)

photo (c) NTSB; Conroe-Lone Star Executive Airport, TX (CXO); September 2014; (publicdomain)

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